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 " 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!

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