Page 27 - ALG Issue 4 2014 Digital Edition

Expert guide to...
Know Your Weeds
Most of us think we have far too many weeds but a weed is really just a plant growing somewhere we think it shouldn’t – a lizard orchid on a football pitch is just as much of a weed as those miserable- looking little tufts of grass sprouting from the cracks between your paving slabs.
Plants succeed in being weedy because they’re tough, persistent, grow fast, grow when other things don’t, or grow so big they smother everything else, produce masses of seed, have ultra-deep roots which are hard to kill and regenerate from the smallest fragment – or any possible combination of these.
Weeds can tell you a lot about your soil. Everybody immediately thinks of nettles growing where the old privy was, and imagine a nitrogen-rich area, but in fact nettles do best on a soil rich in phosphates. Chickweed is the primary nitrogen indicator – if you’ve got a lush growth of it, hoe it
off and put your cabbage plants there. Or onions, pumpkins, potatoes.....
If you’re offered a plot with lots of hop-trefoil or clovers growing on it, and not much else it’s probably a dry, hungry, alkaline soil. Low nutrient levels and poor soil structure can also be indicated by weeds like parsley piert or corn spurrey on thin sandy, pH neutral soils, prone to
capping: or tormentil and sheep’s sorrel on sour acidic ones.
Creeping buttercup and self-heal mark
poor drainage. By looking at how weedlings
are developing, you can find out soil temperatures
without a
thermometer – the
As an organic gardener you probably will expect me to tell you to eat your weeds
– well, nettles when young make a mean lasagne, but don’t bother with them once they start flowering. Another under-rated weed is fat hen, which is very common everywhere and is better than spinach in hot seasons. It’s been calculated that on average, every cubic inch of the first 6in of topsoil in England has around 12 fat hen seeds in, so you might as well eat it – it’ll be making an appearance soon. Try it in
a saag aloo. Field pennycress is another good green when young, tasting as good as rocket but not as hot.
Sally Cunningham is a horticultural consultant based in Leicestershire. As
a dedicated organic grower, designing for wildlife is always one of her main considerations; she also has a particular interest in Asian vegetables. www.askaboutplants.com.
grey field speedwell begins to germinate at 42˚F, that magic level at which
the grass starts growing. Keep
an eye out for the characteristic little
round-oval pairs of seed-leaves,
and when you get a lot of them, it’s time to start sowing broad beans, peas, parsnips, lettuce, turnips, radish.....
Creeping buttercup flowering in rain
As an organic gardener you probably will expect me to tell you to eat your weeds
Lesser bugloss, Anchusa arvensis
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