Tuesday 23 September 2014

Crop Rotation Confessions...

I have a confession to make. Crop rotation on a small plot has always rather baffled me. On a big plot it makes sense - on a big plot you can afford to leave a patch of ground empty in preparation for a later crop, or to sow a green manure in the middle of summer just for the heck of it - but on a small allotment where you want to make the most of every space all year round, it can be a real juggling act trying to get your potatoes out early enough for your purple-sprouting broccoli to go in, or clearing your onion patch in time to sow beans and corn, or figuring out what on earth to grow after you've harvested your squashes as late as October - and who uses exactly the same amount of space for every crop group anyway??

Traditionally, the main groups in a crop rotation are potatoes and roots, brassicas, beans, and 'other veg'. The potatoes are manured to enrich and slightly acidify the soil (preventing scab), heavy-feeding beans follow in the nicely broken-up ground after the potatoes are dug, then (often after an application of lime,) leafy brassicas to make good use of the nitrogen the bean roots accumulate. Then, presumably, you throw sweetcorn, cucurbits, tomatoes, leafy greens and everything else in together after that. Sounds simple enough, but questions abound. Do you grow swedes with the root crops or the brassicas? Aren't tomatoes in the same family as potatoes? Cucurbits take up way more space than anything else! And aren't you supposed to avoid manuring carrots?

I don't know, maybe I overthink these things - maybe I'm just too keen to abide by all the rules and to do it "right". But I think, after eight years on our allotment, I've finally cracked it!

This is partly thanks to slimming down the number of crops we grow on the allotment anyway - we don't grow onions and garlic due to white rot spores in our soil, and we prefer to keep salad leaves and quick-ripening summer crops like French beans, courgettes and tomatoes at home so we can pick them more regularly. On the allotment we grow the lower-maintenance stuff: potatoes, squashes, root veg, broad beans, leeks, and a limited amount of winter brassicas and spinach-type leaves (plus some perennials in a permanent area). We've grouped broad beans, leeks and root veg roughly together: together they take up about the same amount of space we use for more space-hungry crops (potatoes and squashes), and it means we can follow our broad beans (which finish around midsummer) with winter brassicas, thus keeping our earlier-sown swedes in the same area as our other brassicas.

Ladies and gents, I give you our brand new crop rotation plan! (Click pic to enlarge.)

This rotation also allows for two squares to be sown with green manures over winter to add high-nitrogen organic matter to the compost heap, shelter wildlife and protect the soil. Phacelia and field beans are my two favoured green manures since field beans add vital nitrogen to the soil and can be sown as late as November, and phacelia attracts lots of insects and can be sown as late as September. Following squashes with winter-hardy beans means the timing for sowing is perfect; likewise with the winter leaves following the potatoes, and the winter brassicas following the broad beans. And even though we grow most of our beans at home, our allotment soil still gets a nitrogen injection thanks to the broad and field beans. Of course, this rotation doesn't include everything and I should do my best to efficiently rotate our crops at home too, but those on the allotment are the most important ones to rotate: beans for nitrogen, potatoes which are prone to damage from buildups of slugs and eelworms, and brassicas which are susceptible to clubroot, a very nasty fungal disease.

So far it's all going swimmingly. The potatoes are out (an awesome 28kg of Kestrel and 19kg Pentland Crown!) and the winter leaves are in; two rows of chard, two rows of winter spinach and a row of fennel (there's room for more, actually - I must do that). The squashes have finished a little earlier than usual, which means we have plenty of time to clear the soil for winter beans. The leeks, root veg, celery, spring cabbages, kohlrabi and pak choi are coming along nicely and we will slowly harvest them all winter long, making the most of all our space. Brilliant!

There is one complicating factor looming, in that we are planning to clear our old strawberry and asparagus beds (not shown in the plan above) over winter and put them to new use next spring. These two areas don't really fit into the plan so I'm a bit puzzled about what to do with them (and I rather wish we could move our pond and our apple tree into one, which would help us make better use of the other!). Should we grow runner beans or courgettes on the plot again after all? Shall I expand my collection of perennials? Is it time to give in and plant some fruit bushes? Good job I've got all winter to think about it...

Friday 27 June 2014

Score One for Permaculture

When you think of organic growing, there are a lot of things that might come to mind. You might think of nasty organic pesticides such as pyrethrum or diatomaceous earth; you might think of arduous slug-patrols and endless couchgrass; you might think of sterile white insect-proof mesh covering up beautiful rows of crops. But the best method for growing organically, in my opinion (though slug patrols and insect-proof mesh certainly have their places!), is to work in harmony with nature as much as possible - the permaculture way; sustainable and low-maintenance - and we've seen a great example of this on our plot over the last month.

One important factor when it comes to growing in harmony with nature is simply to give plants the right conditions to promote great health, and that means sowing at the optimum time so that plants don't have to struggle. As much as I like the idea of sowing broad beans in autumn so I can pick them super-early the next season, experience has shown this never turns out well on my plot and the plants get absolutely ravaged by pests come April. Broad beans sown from March onwards, however, seem to grow up stronger and have almost no pest problems.

Nevertheless, sometimes the unexpected happens, and a few weeks ago we noticed the stems of just a couple of our broad bean plants were absolutely covered in blackfly. I groaned, but then I looked closer...

There were ladybirds everywhere - at least 15 on the most affected plant - and many of them were busy mating or laying eggs. Knowing that adult ladybirds eat up to 1000 aphids per day, I didn't see much point rushing to squish all the offending aphids or pinch off the tops of the plants! I just left them to it...

A week or two later there were plenty of ladybirds still around, and lots of their larvae too...

And a week or two after that - no more blackfly! Just a few corpses remain on the stems, ants picking over them rather sadly, and the bean pods are well on their way. That's 100% pest control, with no spraying, squishing or other interference from us. Hurrah!

These broad beans are close to where we'd grown some phacelia as a green manure over winter - the phacelia was flowering by this point and covered with busy bees - and since ladybirds tend to like feathery-foliaged plants I presume this is what brought so many to the area. When I finally pulled the phacelia up I certainly found plenty more ladybirds sheltering there! A pesticide-free plot, no-dig beds, and plenty of sheltered places for insects to overwinter are helping make our plot even more hospitable to predatory insects such as these, and there are plenty of other plants we can grow to encourage them too; cosmos, dill, parsley, fennel, angelica, caraway, coriander and yarrow are all good choices which should be left to flower for best effect (slugs ate all my dill - boooo!) as well as flowering herbs such as mint, lemon balm and thyme. They're trickier to photograph, but there are definitely more little parasitic wasps on the plot this year too.

I love it when a plan comes together. Score one for permaculture!

Parasitic wasp laying an egg

Wednesday 28 May 2014


Well, I haven't really been blogging as much as I intended this spring, but there's a very good reason. I've been unexpectedly busy with an exciting new community food project...

I joined the steering group for FoodSmiles back in September when it formed - the outcome of a public meeting run by Transition members as part of the St Albans Food and Drink Festival. The idea was to start a CSA - Community Supported Agriculture - project in St Albans. CSAs across the world take many forms, from meat-shares and food co-ops or 'hubs' to community-run farms, but our aim was to rent a smallish piece of spare land from a local farmer or grower, grow our own produce there, and share it among our members, with the aims of reducing food miles and making food-growing and locally-grown food more accessible to the community.

In April we secured a piece of land at the organic-certified Hammonds End Farm, just outside St Albans. It's small, but it's a lovely spot, with polytunnels already onsite, and we couldn't ask for a more supportive landlord!

Starting late in the spring has meant it's a bit of a race-against-time to get all our seeds in the ground, which is hard clay and very stony (the farmer generously ploughed and harrowed it for us before we arrived, but it still needs lengthy prep before sowing!) and a bad flea beetle problem has meant resowing the first of our brassicas. The polytunnels had some big holes and needed repairs before use (one still does), and the organic certification of the farm, while a really positive thing, means we have to be very careful to use only organic seeds and plants, soil amendments and treatments, and keep strict records of everything we do onsite. So as 'site co-ordinator', I have been quite busy...


But we've got some dedicated and enthusiastic members, we've had some great support from local garden centre Aylett Nurseries, who donated organic compost and equipment to get us started, and it's all go on the site! Our potatoes, carrots, lettuces, parsnips, swedes and broad beans are all growing well, we're raising courgettes and squashes ready to plant out soon, and we're about to fill the polytunnels with cucumbers (from seed), peppers, chillies and tomatoes (from Rocket Gardens).

As you'll know if you read this blog often, bringing food production back home and back to communities is something I'm really passionate about, so I'm enormously honoured and proud to be so heavily involved in a project like this, and very grateful to those with the vision to kickstart it! We can only support 25 to 30 members this year, but we hope to grow and grow, possibly producing eggs, meat, and who-knows-what-else in the future, and truly bringing a new source of local food to St Albans. Its hard work at the moment but the plot's already a wonderful place and I know in a few months it will be bursting with lovely fresh veg for us all - and it's great to see lots of new friendships between like-minded people blossoming too!

FoodSmiles is on facebook and twitter if you want to know more or follow our latest updates. We still have a few membership places available so if you're local and you'd like to join us, get in touch!

Thursday 8 May 2014

Perennial Kale Cuttings

Perennial vegetables have loads of advantages to both the gardener and the planet. Where perennial crops are grown the soil can relax and get on with being great soil with abundant microlife, while ploughed soils for annual crops lose their vitality and are more prone to leaching and erosion. An area filled with perennial plants, which mimics nature, supports much more wildlife than an area that's replanted each year or each season. For the gardener, perennials save on labour and often need less care thanks to their extensive established root systems, and plants tend to suffer less from insect damage. Perennial food plants also get a head start on the new season and can help fill the 'hungry gap' around this time of year, after the winter crops have finished but before the summer ones are ready.

The perennial Daubenton's kale I bought from Backyard Larder last year did really well and was tasty and productive, putting out new shoots at every leaf node, but I neglected to give it the support it needed and it ended up a bit unruly and bent-over - and I had to move it to a pot early this spring to make way for a new raised bed.

Towards the end of the winter it put out loads of new shoots all up and down the main stem, and I saw the opportunity to propagate some new plants from it, to add to my new perennial patch on the allotment and perhaps to replace this original one if it didn't make a good recovery.

I'd never taken cuttings before and I couldn't really find any information on how to take brassica cuttings online, but in January I carefully cut a few shoots from the plant, poked holes in some soil in a deep tray, popped the cuttings in and firmed them down. I left them outside in the cold and made sure to keep them moist. They wilted a bit and some of the outer leaves died off, but then they perked up again and seemed sort of healthy.

When I lifted them after a few weeks, however, they still hadn't formed any roots. So I tucked them back into the soil and tried a second batch, using bigger shoots this time as I thought perhaps they'd have more energy. They looked even worse than the first lot had!

I stuck with both batches though, and after another month or so I noticed some looked different to the others; some looked blueish and dark, while others were a brighter green. I lifted them again and sure enough, the greener ones had lovely white healthy roots.

Another month on, all seven plants have now rooted and are potted up and doing well, albeit at different stages of development! Some of them took as little as four weeks and others took nearly four months, but it just goes to show that a little patience and care pays off. The most important thing is to keep the soil moist and the slugs away! The original plant is now propped up and doing well again but still stuck in a pot, waiting for a new home, and I'm looking forward to planting my new perennial kale plants out on the plot and giving the rest away at our allotment association plant swap this weekend!  :-)

Friday 11 April 2014

Complete Organic Fertiliser

My last post, Grow Your Own Nutrition, was all about how I'm intending to remineralise my soil for the best results in my garden and allotment, and how it's really all about feeding the soil, not the plants - if you missed it please do take a look. The best way to remineralise a soil is to send off a soil sample to a lab, find out exactly what it's got and calculate exactly what it needs, and my new favourite book The Intelligent Gardener can help to do that. But The Intelligent Gardener offers a simpler one-size-fits-all solution too, and because I've got a lot else going on this spring and I could really do with another read-through of the book before I jump in too deep, I've decided to use this recommended 'Complete Organic Fertiliser' (COF) for my plot this year. Steve Solomon, the author, stresses that COF has its limitations and can cause its own imbalances if used year on year, but promises much better results - better growth, better plant health, better flavour and far more nutritious food - than with the conventional organic way of feeding soil just with compost and manure.

There's a version of the COF recipe online here in Solomon's own words, so it can't hurt to share the recipe I've settled on with you here. In the book, Solomon recommends a few other optional additions, but I'm keeping it simple this year and sticking to the main ingredients below:

4 parts seedmeal
Seedmeal is what's left over when oils are pressed, and added to soil it provides a natural, highly-effective, slow-release source of nitrogen as the soil organisms feed on it.

1/3 part lime, 1/3 part dolomite lime, 1/3 part gypsum
The lime provides calcium - probably the most important soil mineral - while the dolomite and gypsum provide more calcium plus doses of magnesium and sulphur, respectively.

1 part bonemeal
This provides phosphorus. There are other things you could use, such as hard or soft rock phosphate - arguably better as it doesn't contain the sodium that bonemeal does - but bonemeal is more sustainable and more easily available, and soil needs a little sodium anyway.

1 part seaweed meal
Seaweed meal is rich in trace elements and also provides plant hormones which boost plants' natural defences.

This mix is to be applied once a year, at a rate of 4-6 litres per 100 square feet, along with a modest amount of compost or manure. If the thought of adding lime to soil every year challenges you, or you're wondering why there's no potassium in the mix (actually, there's just a little in the seedmeal), do go back and read my previous post!

Bonemeal and lime were easy to find in a garden centre, and I ordered the seaweed meal, dolomite and gypsum from The Organic Gardening Catalogue. The seedmeal presented a bit more of a challenge: it's apparently sold as animal feed in the US and Tasmania, where Solomon lives, but here in the UK I struggled to find it anywhere - but I eventually found a friendly local farmer growing rapeseed for oil who was happy to sell me a couple of big bagfuls. It came as quite large pellets, which wouldn't mix well with the powdered ingredients, so I've been stomping on it in a washing up bowl to smash the pellets up.


They don't break down completely - it'd take ages! - but it's a big improvement. I found using a stick blender worked really well too - until the thing overheated. Now I have to buy a new stick blender... Doh!

I've been making COF in small 7 litre batches using 1 litre as 1 part - partly because I have only ordinary-sized buckets to mix it in, partly because I'm using it bit-by-bit anyway as each bed gets prepared for planting, and partly to reduce any effects of the stuff not mixing together evenly: if I find a pile of seedmeal pellets at the bottom of the bucket it's easy enough to remedy on a small area.

It's dusty stuff, and I've had to be careful to mix it (and spread it) when winds are low to stop all the gypsum and dolomite blowing away!

Solomon recommends digging it into the soil, but it can also just be raked into the surface for no dig plots like (most of) mine.

I've spread it over much of the plot already and I intend to use it everywhere. It's too early to see the results, but you can be sure I'll keep you posted!

Friday 4 April 2014

Grow Your Own Nutrition!

Okay, this post is going to be long, and I'm sorry about that, but I promise it will be absolutely worth it! During the winter I had the pleasure of reading two fascinating and wonderful books about soil nutrition and its impact on our health, and I've got to tell you why my approach to growing food will never be the same again.

The first book, which I just happened upon while idly browsing for free Kindle books one day, was Beyond Organic: Growing for Maximum Nutrition by Dr Jana Bogs. It kicks off with an analysis showing how vastly different the levels of vitamins and minerals could be in vegetables grown in different soils across the US: "not by just 10 or 20 percent, or even a two-fold difference..." but "...as great as 1,938ppm (parts per million) iron in some tomatoes as opposed to only 1ppm in other tomatoes of the same variety. This is nearly a 2000-fold difference!" Not rocket science, is it, to work out that more nutritious soils would grow more nutritious veggies? But I'd always assumed that a carrot was a carrot was a carrot, and any variations would be so small as to be irrelevant.

It's funny the way we often just go on doing things the way we were taught, without really thinking about them. For years I've believed it when I was told that all my soil needed was as much compost as I could make, plus a bit of horse manure or fish, blood and bone for a boost, and some lime every few years to keep the pH level where it should be. 

Nutrition levels in our food have dropped off by around 75% in the last hundred years or so. Concerns about depleted soils and nutrition deficiency leading to poor health in Americans were first brought to the US Senate way back in 1936. Between 1948 and 1991, Australia's 'Commonwealth Scientific and Industrial Research Organization' recorded an 80% drop in vitamin C in apples, an 82% drop in magnesium in broccoli, a 75% drop in iron in potatoes and an 89% drop in calcium in potatoes, and a similar American study showed that roughly half the vitamins in vegetables had significantly decreased between 1950 and 1999. An analysis on canned peaches over a hundred years old found that they contained more vitamins, even after a hundred years in a can, than today's canned peaches do! We'd need to eat a huge amount of today's fruit and veg to get the same nutrients we would have got from our 'five-a-day' a hundred or a thousand years ago. Is it any wonder we're all fat and sick??

Dr Bogs explains some of the complex interplay between nutrients in plants: minerals taken up by their roots activate enzymes which create the proteins, fats and vitamins we need. Though plants need only around 20 nutrients to survive (some say up to 42), if given a fuller range of nutrients they are capable of generating all the 50+ (some say up to 90) nutrients that we humans need. In other words, a vegetable might have everything it needs to reach maturity looking and tasting good, but that doesn't mean it has reached its full potential by producing all the nutrition it can, and should, contain: plants pass on a certain amount of nutrition from the soil (iron, copper, magnesium, calcium) but they're also little factories producing fatty acids, proteins and vitamins, as long as they have the building blocks to do so. You might have plied your plot with N:P:K fertilisers, but have you ever wondered whether your veggies get enough zinc, cobalt, boron, molybdenum or selenium? I hadn't!

The second book, The Intelligent Gardener: Growing Nutrient Dense Food by Steve Solomon, was even more eye-opening and exciting, not to mention more practical, offering a full hands-on approach to finding out what your soil needs and making it the best it can be, and I have to thank Douglas of @SweetPeaSalads for recommending it to me! This book busts some myths about the usual organic approach to feeding the soil, and offers a really good and easy-to-understand lesson in soil science. Solomon speaks from a broad range of experience from gardening on a variety of soils in several different parts of the world, and tells of healthier, tastier plants, a complete halt to fungal disease, and dramatic improvements in his own health when the soil on which he grows his food is properly nutritionally balanced. He also keeps a free online library - The Soil and Health Library - full of books, papers and studies on holistic agriculture, the connections between soil and health, and more, and he draws heavily on the works in this library to explain his theory and method.

He particularly highlights a study published in 1939 by one Weston Price called Nutrition and Physical Degeneration. Price visited remote communities around the world; tribes and isolated villages that as yet had no access to the mass-produced "foods of civilization", but survived on what they hunted, foraged or grew on a small scale locally with old methods. Despite his subjects having a wide variety of colours and shapes, of diets and of lifestyles, across the board their health was far, far better and when analysed, their foods were found to contain a huge amount more nutrition; for example, the primitive people's diets contained at least ten times more vitamins A and D than the American diet even back in the 1930s! Steve Solomon believes that the ideal human diet "has more to do with the soil food comes from than which foods are chosen"; some of these people ate no animal products while others ate virtually no vegetables, and others subsisted on just fish and oats supplemented with a few leafy greens. You can read Solomon's in-depth review of Price's book here, and I highly recommend it.

It would be impossible to share everything of importance in The Intelligent Gardener here - it's a fabulous and fascinating book - but here are my main take-aways:

Leaching is the factor with the biggest impact on nutrient density. Leaching is what happens when soil becomes saturated with rain, which dissolves a lot of the soil minerals and eventually drains downward carrying those minerals with it so that they end up in the subsoil or offsite altogether. Leaching is worse in climates where evaporation is also low - warmer weather slows leaching - and in climates where there is a lot of heavy rain in a short period of time. It's also a great deal worse where soil is left bare. Some nutrients leach out of soil more easily than others: calcium goes fast, while potassium tends to get left behind. This leads to imbalances.

Loss of soil microlife and organic matter is another major factor that harms nutrient density, since micro-organisms help to release the nutrients from the soil for use by plants, and high-quality humus holds a lot of nutrition in the soil and helps prevent leaching! This isn't generally a big problem for us organic food-gardeners, but industrial farming methods have devastated agricultural soils.

Compost isn't enough! Composting waste from the plot to feed the plot cannot provide all the nutrition the plot needs - unless the plot is already perfectly balanced. In fact, feeding a plot exclusively with compost from the plot will only magnify existing imbalances! There's a sustainability discussion to be had here: feeding your plot with compost alone is a permaculture ideal; a natural recycling process where we make the most of our waste to fulfil another need without importing costly additional materials from elsewhere. But Solomon explains that a soil can virtually sustain itself nutritionally - once it's properly healthy and balanced and cared for.

Remineralisation is the answer, Solomon says. Soils that have not been cared for properly have lost their ability to stay balanced, and their mineral content has been devastated. Solomon's own experiences and research (and Jana Bogs' studies) show that remineralised soil allows crops to reach their full genetic potential, enjoy proper health with much less chance of pest attack and disease, and provide the maximum nutrition for us.

Total Cation Exchange Capacity (TCEC) is a measurement (calculated in a lab) of how much minerals a soil can hold. Clay and humus particles in the soil have a tiny electrical charge that makes positively charged mineral particles in the soil attach to them - a bit like static cling. These positively charged particles are called cations, and include calcium, magnesium, potassium, sodium and others. The clay and humus particles have a set number of 'exchange points' where cations can stick, so a soil with lots of clay and humus has a high TCEC and a lot of these exchange points, and a light sandy soil with very little organic matter has a low TCEC and few exchange points. Some cations cling harder than others: calcium will always take first priority, magnesium second and the others will follow suit if there's space left. Solomon likens the TCEC to the number of shelves in a pantry. Calcium will fill up the shelves first and the others fill up the gaps in order. If the shelves are empty, they just fill up with air - hydrogen actually, from the soil water. As well as from the TCEC, plants can also get nutrition from the soil solution: mineral particles in the soil (or in slow-release fertilisers) breaking down slowly in tiny amounts and dissolving in the soil water. But that soon runs out and needs recharging. The soil solution is like plates on the table. When the plates are empty they can be refilled from the pantry (the TCEC). The bigger the pantry, the longer the meal goes on. Thus while a plant relying on nutrients in the soil solution would require very regular feeding to keep up with its needs, the TCEC buffers plants against nutritional ups and downs: with big reserves, their plates are never empty!

Balance, balance, balance. It's not about having a certain weight or volume of each nutrient in your soil, nor about throwing all the nutrients you can at it; too much of a good thing can lead to overdosing and cause even more problems. Instead, it's all about balance and the interplay between the nutrients.

Not all compost is made equal. As we all know, organic matter is vital for healthy soil. It improves texture, structure, and moisture retention. Most crucially, it feeds soil life, and it holds anions (negatively-charged mineral particles such as phosphorus, sulphur, nitrogen and boron) in the soil. But Solomon warns against adding too much organic matter and recommends only a 1/4" to 1/2" inch layer per year! Too much compost, he says, can overload the soil and its nutrients can end up just going to waste. He also warns that you never know what you're getting when you buy in compost (or organic waste to compost yourself); it may contain contaminants, or you could be importing unbalanced material that adds to your soil's imbalances without you knowing it. Most crucially, he teaches that much of our home-made compost (and shop-bought compost) is only partially decomposed organic matter, but our goal should be truly mature humus...

Humus and clay, clay and humus. These are the two most important components of soil, and they must both be present in abundance to hold a lot of nutrition. Humus is organic matter that has broken down to a point of stability and will change no further. It stays in the soil, instead of breaking down and disappearing. And while clay holds cations in the soil, humus holds both cations and anions. But great humus needs clay to form properly, so it will only form in your compost heap if you add enough clay to the heap as well. Solomon recommends adding around 5% by volume soil, of which 40% should be clay, to your compost heap. If your soil doesn't contain much clay, he recommends finding some, creating a clay slurry with water in a bucket, and sprinkling it generously between layers! Humus might also form in the ground when you add your partially-decomposed compost to a clayey soil - but when added to a light, low-clay soil, little humus will form, if any, and the organic matter will rot away to nothing, and so light sandy soils have great difficulty building up a useful level of organic matter.

Calcium is arguably the most important mineral in a garden soil, not because plants need a lot of it, but because it is critical for good soil structure: not enough calcium but too much of the other cations (especially magnesium) leads to a closed and airless soil structure in which microlife cannot thrive and other nutrients remain unavailable. Calcium is also the mineral most often lacking, as it's so easily leached away. A soil's TCEC should be around 68% full of calcium.

Magnesium takes second priority after calcium, when it comes to sticking to these exchange points in the soil, so it's the magnesium/calcium balance which will most often cause a problem. Magnesium is present in dolomite lime, often used by organic gardeners, so care must be taken to avoid an excessive build-up. Magnesium should fill around 12% of the soil's TCEC.

Potassium always rolls to the front of the pantry shelves, so if there's an abundance of it, plants use it first instead of reaching to the back for the other cations. When plants have lots of potassium they make lots of sugars and starches, but fewer proteins and vitamins and other more important nutrients. An excess of potassium, therefore, can boost yields, but those yields will be lower in nutrition than they should be, and higher in calories. Potassium can accumulate in soils because it doesn't leach away as much as other cations, and because imported composts made with hay, straw and woody wastes are often very high in it (potassium accumulates in the structural parts of plants; the trunks, barks and stems). I guess endlessly throwing N:P:K fertiliser at a plot might well add to this imbalance too, and presumably potassium is a particularly beneficial yield-booster for commercial growers whose primary concern is the size of the crop. Solomon recommends a soil balance that leaves potassium "just a little bit scarce" - just a few percent of the TCEC - for crops with the highest nutrition.

Sodium. We all know salt isn't good for most plants, but a small amount of sodium in soil is crucial and some crops need it. However, Solomon warns that growers using tapwater to irrigate their crops should be aware of the sodium level in their irrigation water. Annually, twelve inches of water containing 50ppm sodium would bring 200lbs per acre of sodium! There's something I'd never considered before! My local mains water contains an average 17ppm sodium, according to an analysis on my water company's website, but I have no idea how many inches of it I put on my soil... There should be around 1-2% sodium in the TCEC.

Phosphorus is a controversial soil amendment, since it is mined from the ground and we are steadily running out - but even a slight deficiency slows plant growth. Many agricultural soils are severely depleted of phosphorus and heavily dependent on phosphate fertilisers, but a healthy balanced soil can hold on to phosphorus for decades, because phosphorus is held in the soil by humus. If it fails to connect with humus, it soon connects with other minerals and becomes insoluble iron phosphate or calcium phosphate instead, and remains unavailable to plants long-term. Solomon suggests there should be around the same amount of phosphorus as potassium in soil, but that it should be added gradually over a number of years to ensure as little as possible goes to waste. Bonemeal provides a sustainable source, but comes with additional sodium and calcium too.

Nitrogen is crucial for healthy green growth: it's vital for production of the plant protein chlorophyll, which plants absolutely depend on for photosynthesis and energy. Dark leafy greens grown on fully mineralised soil can contain up to 20% protein - as much as beef steak! Nitrogen is released when soil organisms feed on organic matter - annually, every 1% of organic matter existing in a soil will provide 15-25lbs of nitrogen per acre, and to produce a good crop, 100lbs/acre is needed. So a healthy soil with 4-7% organic matter should have plenty of nitrogen available (although if it is hitherto dependent on nitrogen fertilisers, it might need weaning off them first). Solomon also advocates digging in leguminous green manures to provide nitrogen naturally, and points out that a healthy stand of field beans can provide the full 100lbs/acre needed.

Sulphur is a really interesting nutrient which helps plants to form amino acids (proteins) and enzymes, and boosts flavour. While we see sulphur as a fungicide and dust it on our plants as a defence, Solomon suggests that fungal disease is actually a symptom of sulphur deficiency, and describes how the onion root-rot on his plot completely disappeared when he rebalanced his soil. This is great news for me, as I've had to give up growing onions on my allotment thanks to my white rot problem! Sulphur is another anion, held in the soil by humus, and when it dissolves into the soil solution it bonds with cations to become a water soluble sulphate (iron sulphate, calcium sulphate, zinc sulphate etc.) Thus too much sulphur can leach cations from the soil - or it can be used, with care, to deliberately deal with a cation excess.

Micro-nutrients and trace nutrients are vital for maximum plant health and maximum nutrition too, and Solomon reveals the amounts needed for good balance and recommends amendments such as seaweed or Azomite for adding trace elements. Surprisingly, he's not such a fan of rock dust, and his analysis of it makes interesting reading.

pH. Wow, now this is important! pH is NOT the be-all-and-end-all of soil health, but a side-effect of the chemical and microbiological activity in the soil. It's not really as meaningful as we tend to think, and it fluctuates in a much more complex way than most of us know! pH stands for 'potential hydrogen' and is defined as the density of hydrogen atoms in water (or in a solution of a substance, such as soil). All the exchange points in the soil must always be filled up, so if there is no calcium, magnesium or other useful minerals around, hydrogen atoms from the water in the soil will stick instead, and the soil will contain a lot of hydrogen and have a low pH (an acidic soil). A soil rich in cations such as calcium and magnesium, on the other hand, has very little hydrogen and a high pH (an alkaline soil). So the pH of your soil can indicate how nutrient-rich it is - certainly an acid soil is lacking in cations. BUT a soil high in cations (alkaline) may have completely the wrong balance of cations and still benefit from liming, and in fact, the liming might not raise the pH further (since the new calcium ions knock off and replace the excess magnesium, potassium or sodium ions) but allow it to fall because correcting the balance allows the microlife to thrive again and kicks off the normal cycles of nitrate release and so on!

Soil testing is the only way to really know what's going on in a soil, and this is the method Solomon recommends to get the maximum potential out of any food-growing plot. The book explains how to take a soil sample and where to send it, and provides worksheets for readers to interpret the results and work out a perfect prescription of amendments for their soil. He also acknowledges that a soil test and a bunch of calculations won't be for everyone and might be severely over the top in a very small plot - so he offers a generic one-size-fits-all solution too, which he promises will greatly improve virtually all garden soils and increase its benefits year by year. He calls this his Complete Organic Fertiliser, or COF.

The Intelligent Gardener is a garden-changing book - maybe even a life-changing book - and I thoroughly recommend it to all home-growers. It's the kind of book that, once you've read and understood it, you just have to put into action. Steve Solomon believes that "many of our current social problems would also vanish by themselves, if only the mass average health of people were uplifted", and I'm inclined to agree, having seen the enormous variation possible in the nutrient content of our foods, and considering how far the impact of an unhealthy soil can reach into every part of our diets. If I'm going to grow my own food, then I want to do it properly and really get the best out of it. And if brilliant health is within my grasp (and my family's), just by changing what I feed my soil... well, no-one's getting in my way!

I intend to have my soil analysed and to remineralise it with The Intelligent Gardener's guidance, but not this year, with so much else going on. This year I'm trying Steve Solomon's Complete Organic Fertiliser (more on this in a future post), both on the allotment and on my beds at home, and I have high hopes for some excellent results.

I hope you're itching to go out and read this book for yourself right away! (I don't get anything for that, by the way.) But if money's tight or you're not convinced yet, there are three great interviews with Steve Solomon available free on the Ruminant Podcast website, here, here and here - do have a listen. And watch this space for more on Complete Organic Fertiliser...

Monday 31 March 2014

Got Mycorrhizae?

Fungi are amazing organisms. They're everywhere, but their lives go on unseen, in secret, for the most part. They're crucial for decomposition and recycling of waste. They grow like plants but are made of chitin like insects and other invertebrates and, just like humans, they produce vitamin D when exposed to sunlight - in fact, some consider fungi to be more closely related to animals than to plants. They can absorb toxic waste and chemical pollutants, using them as food and rendering them harmless. They can MAKE IT RAIN! Their rootlike mycelium - the main body of the organism - can spread underground for miles (the largest fungus on earth is believed to be a honey fungus which covers nearly nine square kilometres in Oregon's Blue Mountains!) while the mushrooms and toadstools we see on the surface are just their flowers and fruits! And it's fungi that form the vast underground network which scientists believe allows plants to communicate, warning each other of pest attack and other troubles.

These mycorrhizal fungi - fungi which connect to the roots of plants and form a symbiotic relationship with them - have other benefits for their hosts too; a vast mycelium acts as a secondary root system for a plant, bringing nutrients and water from far deeper and further away, effectively increasing its root system by up to 700 times! Plants with roots colonised by mycorrhizal fungi establish faster, grow better thanks to the additional nutrients, have more resistance to pests and disease, and suffer less in drought. It's estimated that 90% of land plants have associations with these fungi. Just one gram of woodland soil can contain over a million microscopic fungi, and in one square inch of decomposing organic matter, such as a decaying tree trunk, there can be 70 miles of mycelium. The stuff is everywhere!

Well, not everywhere. Guess where you won't find mycorrhizal fungi...

You won't find it in the kind of sterile shop-bought compost you raise young plants in. And you won't find it on highly-cultivated, regularly disturbed allotment soil. Nope.

So I think it's pretty cool that you can now buy it in a packet. :-)

The fungi spores, native to the UK and grown here, are dried and bound in clay. To use them you just sprinkle them in the planting hole when transplanting, or add them to a drill under a sprinkling of soil before sowing seeds. I have put mine into an old herb jar with a shaker top for easy application!

Needless to say, I will be using this this year, especially under my new perennials, and have already added it when planting my strawberries and asparagus, and sowing my broad beans. Of course, switching to no-dig growing and using ground-covers will mean that fungi can survive much better in our soil from now on, and should colonise the area nicely, so personally I can't see myself using it year on year, but it certainly looks like it has great benefits for growers whatever their methods (look here for some photos comparing plants with and without mycorrhizae) and the RHS particularly recommends it when planting out trees, roses and shrubs, to ensure less transplant shock and help plants establish faster.

Mycorrhizal fungi apparently don't help brassicas, since brassica roots release a natural anti-fungal defence which stops them thriving, nor acid-loving plants such as cranberries, blueberries, heathers, azaleas and rhododendrons. Some other plants however, like grapes and roses, depend heavily on the mycorrhizae and can really struggle without them, and a few species of orchid cannot live without them at all.

It's crazy to think that our traditional method of digging the soil over before growing crops actually breaks this beneficial natural relationship that does so much good in the wild, and stops us benefiting right where we need it most. It's another one-up for no-dig gardening, and I can't wait to see the results!

Saturday 29 March 2014

Allotment Week, Part Three - Green Manures and Ground Covers

I've dabbled a little with green manures before - mostly scattering phacelia seeds here and there at the last minute of the growing season and then cursing them when they finally appear the following spring right where I want to be planting stuff, and I can't bear to get rid of the lovely flowers before the bees have made the most of them... But last autumn I made my first serious attempt at using green manure properly.

The idea, in case you're not familiar, is that rather than leaving soil bare over winter (or at any time), you sow a cover crop of some sort. This crowds out weeds, keeps the fungal organisms in the soil happy, and protects the soil against leaching, erosion and so on - and when you're ready to plant crops again you dig in the vegetation to add organic matter to the soil. Now that I've seen our plot flood, I can see how important it can be to have roots in the ground, keeping the soil together and preserving its structure in case of extreme weather. The problem I typically have, though, is that I clear my beds too late to sow anything, or, as with the phacelia, poor planning means I want to plant right where a cover crop is doing its thing. I've also always been a bit wary about adding to my weed problem by experimenting with certain green manures which are reportedly not-so-easy to kill off when you're done with them! But after a lot of reading, I've identified a few green manures that I think suit my way of working:

Field beans, often grown for livestock feed and much-resembling a branching broad bean, are winter-hardy and germinate right up to November, so I can get away with sowing them really late in the season. And being in the bean family, their roots fix nitrogen in the soil.

Phacelia needs sowing by September latest, so I'm gonna have to try harder to clear some space for it late summer (maybe after the broad beans...?) but I think it's well worth persisting with for the lovely bee-friendly flowers it produces around May - if I can manage to leave it that long. It'd be ideal for whatever bed I'm going to grow squashes on, since they don't get planted out until May or June.

Mustard is a quick grower which is killed off by frost and can be left where it dies to decompose and mulch the soil. It's not quite the same as having something growing over winter, but I'm interested in giving it a try this year and seeing how it works out. Mustard is said to help keep soil pests under control too, so it might be good to grow this before potatoes.

White clover is hardy and long-lasting, and can be used as a 'living mulch' around perennial or widely-spaced plants. It keeps weeds down and has bee-attracting flowers in the summer, AND it fixes nitrogen. I'm going to start introducing this all over the place: we have already sown it over what is to be our squash bed (too late to sow phacelia here now for flowers by May) and I will start to scatter it round the edges of the perennial bed, letting it spread naturally. If it's growing where I want to plant, I'll simply pull it up to clear a space.

Buckwheat is a quick-growing summer green manure and to be honest, I'm not sure if I'm really going to fit it in anywhere, but like phacelia it has wonderful flowers, loved by insects, and it seems easy to deal with, so I wanted to give it a try and bought some seed anyway...

Back to 'allotment week', and our third big task was to clear last year's green manures and sow a new one. After our potatoes were harvested early last October we sowed field beans in their place, and they've grown pretty well through the mild winter, reaching a height of nine inches or so. But plans have changed since last autumn and I wanted to get some clover started here, so it was time for them to go.

Switching to no-dig gardening means we won't be able to dig our green manures into the soil, but instead we can cut down the growth and either use it as a mulch and let it decompose naturally on the surface, or add it to our compost heap. Leaving the roots in the soil means they'll add loads of nitrogen. Just look at the nitrogen-filled root nodules on this field bean stump I pulled up by mistake!

I cut the beans down at the soil surface, trying to get every shoot to reduce the chance of regrowth. I'm sure some of my allotment neighbours must have thought they were up-and-coming broad beans I was cutting down! The greens made a nice leafy layer on the compost heap.

I hand-weeded the whole bed after this - the beans don't keep weeds down as well as some other green manures are supposed to and there were quite a lot of young dandelions, docks and pineapple weed around. Then I raked and watered in some white clover seed over the whole bed. Hopefully it will have a good chance to get established as a living mulch before I plant the squashes out.

Mulching round plants helps to keep weeds down, reduce evaporation, and absorb excess rainfall in wet periods. A living mulch has all these benefits and more! It can attract and provide shelter for beneficial insects, it doesn't need replacing so often, and it has even been shown to decrease pest attacks in some vegetable plants. I'm really looking forward to seeing how this works out! Earlier this week I also read this interesting post by Alison of Backyard Larder, which talks about using edible plants such as wild strawberries and lambs lettuce as living mulches - something I am going to have to give some thought to now! I'm certain claytonia, one of my favourite home-grown salad leaves, would make a pretty great groundcover too, but judging by the way it gets everywhere in the garden I think it'd be a bit risky on the plot!

We did sow a spot of phacelia last year too, scattering it in odd patches where I pulled up individual squash plants. You can see what remains as a clump in the third bed in the picture at the bottom. I'd really like this to flower before I want to sow my root veg there... I don't think it's going to happen, but I'll wait and see, and if all else fails maybe I'll scatter a few seeds out of the way for the bees (and me!) to enjoy the flowers later in the summer!

So that's it for allotment week. We didn't get our potatoes in like we wanted to - no big deal as it's early yet - but we really did get a good headstart on the season, and did a lot of those little jobs that usually get pushed to the bottom of the list. If you follow this blog I'm sure you'll agree it's probably never looked this neat and tidy! Now, bring on some warmer temperatures and let's get some crops out there!

Thursday 27 March 2014

Allotment Week, Part Two: Goodbye Digging!

Think about allotments or growing-your-own, and digging is probably one of the first activities that comes to mind. But digging, it seems, is not the best choice for the soil, and more and more gardeners are giving it up. I've been following the work of gardening author and teacher Charles Dowding, who promotes no-dig gardening, and the efforts of Roy and Tanya from Pushing up Dandelions, who created a wonderful and productive no-dig plot from scratch last year by bringing in mulch, manure and compost from offsite, and the advantages are clear:
  • It preserves and protects beneficial soil life: the six legged kind, the wriggling kind and the oft-forgotten complex fungal organisms that weave their mycelia through the dirt.
  • The soil develops a more stable and open structure, which admits air and water, drains well and can be walked on (carefully) without compacting.
  • The soil surface stays loose and is less likely to harden into a crust.
  • Leaving roots and other organic matter in the soil to decompose naturally adds structure and nutrients.
  • Regular digging means old weed seeds in the soil are constantly brought to the surface where they can germinate and grow.
  • Most crops actually establish better and grow faster in undug soil, thanks to its improved structure and microlife.
  • Digging takes a lot of time and can be jolly hard work!

(For more about no-dig gardening, check out this handy leaflet from Garden Organic.)

When we started out with our plot, I don't think we could possibly have avoided digging: the couchgrass problem was severe, and we couldn't have afforded to ship in enough compost to just cover it up - and anyway we wanted to grow in the fertile allotment soil, not shipped-in compost from goodness-knows-where! But now, having dug annually for a few years and finally gotten rid of most of the grass across the main growing area of the plot, we're making the big switch to no-dig gardening...

The two beds in the foreground of the pic above have only needed hand-weeding for the last year or so. We helped the third one along last year by basically digging all the soil out of it to about a foot deep, lining it with a couple of layers of thick cardboard to smother the grass, and putting the soil back minus the grass roots! Our squashes grew well here last year and again, it only needed hand-weeding. The cardboard will decompose eventually, but hopefully it will take long enough to smother and kill off any remaining perennial roots below.

Our card-lined no-dig squash bed!
The fourth bed, way over near the compost bin, is still chock-full of grass. We're planning to grow potatoes there this year and Eddie has started to dig it, but those plans may yet change to no-dig plans...

You will have noticed we've put in some (hopefully) permanent paths now, too, lined with weedproof fabric, edged with bricks and filled in with woodchip. This added structure will really help us keep control of things better, I think, and provides something of a barrier to any remaining weeds and those creeping in from the sides.

Taken last summer
So anyway, now we've got a big weed-free area, we're giving up on our thoroughly weed-ridden strawberry and asparagus beds, and planting a new perennials bed was our other main task for 'allotment week'. Below you can see how our old strawberry bed looks right now, and the asparagus bed is in the same state. Hand-weeding them every year when the couchgrass is obviously still so established is just soul-destroying. We were obviously very naive about how long it would take and how hard it would be to get rid of the perennial weeds!

Our old strawberry bed - yuk!
Our new perennial bed has 24 strawberry plants in two raised beds (Florence, Mae, Lucy and Albion runners transplanted from the old bed and from home) and two new rows of asparagus (10 x Gjinlim and 10 x Backlim). Eventually we'll also plant some globe artichokes, a perennial kale or two, and some herbs!

Asparagus crowns going in the ground
So here it is: our new perennials bed (with fox protection on the far raised bed, as we keep finding decomposing animals and bones in it!). There are still a few swedes and leeks here too, but we're getting through them fast now. It won't be long before the asparagus is popping through the soil and the strawberries start leafing up again!

In the meantime, I've taken some cuttings from our perennial Daubenton kale to go here...

...and I'm raising Green Globe artichokes from seed at home. They say you get a lot of duds growing artichokes from seed, so I started by sowing 20 seeds, and culled the weaker ones from the 16 that germinated, so now I have ten. I'll be sure to get rid of any others that don't keep up, and if there are still more than I can handle, I'll take the surplus to swaps! I have bought artichoke plants before but they struggled and died (they were in the troubled bottom end of the plot, where the compost bin now is) and they were expensive! Seed is much cheaper!

Of course, there's still some digging to do: we need to start from square one on the remaining grassy areas now, including the old strawberry and asparagus beds. But it's great to know we can now start to say goodbye to that back-breaking chore we had to get through each season before we could start the fun stuff, and I know the plot's going to be much more productive for it!

Tuesday 25 March 2014

Allotment Week, Part One: A Good Tidy Up

Every year, in the middle of March, Eddie and I take a week off together with the primary intention of getting the allotment in order for the growing season ahead. To be honest, it rarely works out like that; weather or household tasks usually get in the way and we don't tend to get as much done as we'd like - if I recall correctly, the plot was under snow this time last year! - but the intention is there. Well, last week was our "allotment week 2014", and I'm pleased to report that it was rather jolly good!

First things first: After seven years in the elements, our trusty storage bench neither functioned as a bench, nor kept the contents dry any more, and definitely needed replacing. You gotta have somewhere to sit!

I'd have liked to get something non-plastic, but wooden options are much more expensive and require more care and maintenance, so I confess we went for plastic again. We did dutifully take the old one to the 'rigid plastics' recycling bin at the tip though!

Our new bench looks pretty good and seems a bit more insect-proof than the first! Without a shed, we really rely on this space to keep all our tools and bits and pieces.

Next, we badly needed a new compost bin. Our old one is seven years old, just like our bench, and literally falling apart, with one side threatening to burst and spill compost all over the path...


With a few pallets from my brother's workplace and a bulk pallet delivery from the local Wood Recycling Centre, we soon had a new one built at the opposite end of the plot.

We moved it here for a few reasons: first, it's the shadiest part of the plot, under an elder tree, and the soil seems to be very poor here and full of roots; nothing we've planted here has ever done well. Second, the grass and nettles here go crazy and it'll be a sure way to stamp them out (while cutting any remaining nettle growth to feed to the compost). And third, we can use the sunny and now super-fertile spot where the old bin used to be for something else! Once we've finished deconstructing the poor thing and moved all the half-finished compost, that is...

You might have noticed we built a little flower bed next to the compost bin too, alongside the path. I lined it with thick cardboard to try to keep the grass out, and in it I've planted cowslip, forget-me-nots (not shown), wild pansies which self-sowed elsewhere on the plot, and some primrose seeds. I'll pop a few bulbs in later in the year, too. I'm not exactly sure which of these plants will thrive in this little semi-shaded spot and which won't, but hopefully it'll soon be a mini haven for pollinating insects!

Speaking of attracting wildlife, the pond needed a bit of TLC too. It was so overgrown this winter that we pulled basically all the vegetation out and then replaced a few small bits to regrow. Then the site flooded, and the pondweed (and the tadpoles) all floated away. Hmph. So we replenished it with oxygenating weed and put some barley straw in it to tackle the algae that's covering everything. It's looking much better already, and the water's so clear we can see the big fat frogs at the bottom. (It's rather silted up: the 'bottom' isn't nearly as deep as is used to be - so I think we still have more work to do on it...) Now when will those big fat frogs give us some more tadpoles? That's what I want to know!

The flooding, the inability to put anything else in our compost bin lest it exploded, and some neglect over winter had really left the whole allotment in a bit of a mess. The once-lovely blue frames round our beds are rotten now and fallen to pieces (and we're gradually replacing them with brick borders), our table made of bits of pallet fell apart when we tried to move it, and there was flood debris lying around here and there. So before we got down to any, like, actual gardening, we spent some time giving the place a good tidy up too; moving heaps of weeds from last autumn to the new compost bin, bagging up rubbish, and piling up stray wood. Quite a lot of stray wood... Now do we drag it all to the dump, or is this the time to give hugelkultur a try, hmmm...?

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