I've been chasing this subject on the net all evening (I need to get a life
). Interesting results.
The only mentions I can find for huge crop claims are from sites who want to sell you something - the sellers of potato barrels etc - and isn't it fascinating that the lift-up panels on a potato barrel are never more than a foot high? There are, however, lots of people without an axe to grind propounding the container method, but every one I've found so far mentions smaller containers. Even the "grow 'em in tyres" brigade don't advocate over three tyres (and with the seed potatoes planted halfway up the bottom tyre, how much height does that leave?). Bob Flowerdew states that earlies will grow well in containers but you won't get an increased yield (so you were right, Clara
) but you will get an increased yield with maincrops. However, that increase is compared with not earthing up in containers - in open ground, the yield will be even heavier.
I am rapidly becoming convinced that one seed potato, in a normal growing season, will grow more potatoes in the single cubic foot above it. I am also becoming convinced that the "development of side shoots" argument is biologically true but unattainable (in any meaningful way) in practice. Those side shoots nearer the top of the plant would need to be left alone for much longer to develop into a usable potato. I planted some Swift this year (and yes, they're bloody fast) and even they took six weeks to get to the top of the container. I assume that at least another six weeks would be needed for the top layer of developing potatoes to reach usable size - 12 weeks in all, so why did I bother planting Swift?
And to top it all, once you're in the area of keeping potatoes growing for that long (or even longer), the threat of blight is getting more and more pressing.
Ah well - the Great Potato Debate will no doubt continue and, as is my wont, I'll probably have changed my mind again by tomorrow.
But in the meantime, I'll be looking for 18" containers, I think.
Mike
