As well as my usual maincrop of Kestrel potatoes on the allotment, I'm growing spuds in sacks in the garden this year for the first time. I started the first ones - three 'Foremost' earlies - in late February, with a covering of fleece, against the wall of the house where it's a little warmer than in the open. They were growing by March 20th, when I sowed more 'Foremost' and some 'Charlotte' in two more sacks.
They all grew pretty well, and I earthed them up periodically until the sacks were full to the top. The foliage was so big and healthy I eventually had to stake it back to keep the walkway round the side of the house clear. But they took a long time to flower and I'm not even sure they all did - I blame the gloomy weather - and when I had a rummage around in the soil of my earliest-planted potatoes in late June I was dismayed that I couldn't find a single spud! Early potatoes are supposed to take 10-12 weeks from planting to harvesting - this was at around 17 weeks!
But I had broken quite a lot of the foliage off by accident when I was trying to keep the walkway clear, and realised that that first early planting wouldn't be able to grow much more anyway, so a couple of weeks later I gave in to curiosity and emptied the sack. I found the soil rather dry - apparently all the rain we've been having didn't reach them enough in the shelter of the house and didn't penetrate deep enough into the sack - but at the bottom of the bag I found several handfuls of beautiful firm white tubers. Phew! Some of them were tiny and I expect they still could have got bigger with more watering and more time (and without having their leaves broken off).
Fresh potatoes are so delicious, and we ate them up quickly in a Ligurian pasta dish with green beans and homemade pesto, and boiled and buttered with a pie. My faith is restored that something really is happening in the other sacks, and I quickly replanted the first with my last two 'Charlotte' seed spuds - I have ten 'Melody' spare too so I'll keep the cycle going when I harvest the others. Shrivelled-up seed potatoes that have been chitting since spring grow like the clappers - they were up in less than a week and growing at an incredible rate!
I'm a bit confused that all the potatoes harvested were right at the bottom of the sack - I thought the whole idea was that earthing up encouraged more tubers to form higher and higher up. I did find a tuber high up in another sack while rummaging, so this obviously can happen to some extent. But another piece of advice is to plant tubers in levels, so that you have more plants per sack, each producing tubers at different heights - I suspect this may be more productive and I think I'll try it next time...