Dirty secrets: Get digging now and reap the benefits next spring

Someone at the allotments has been doing their homework. "I looked on an old map," says the green-eyed Irishman three plots down from me, "and there used to be a stream running right down the middle here." He draws an imaginary line in the air, bisecting my plot. I sigh, thinking of what this means in terms of extra digging; I had always wondered why the soil here was such heavy clay, treading underfoot into something akin to what you are given at primary school for modelling purposes.

Like many beginning plotholders, I spent much of 2008 with half my allotment covered with cardboard and black plastic. This has dramatically reduced my work in terms of clearing weeds and their roots, but now it's time to cultivate, with one eye on the planting season to come next spring.

It's the time of year when the mind turns to digging. From a plane, flying north for a funeral last week, I noticed how many fields were ploughed and ready to sow – the autumn browning of the countryside. At the allotments, too, the diggers are keen to start work, cutting back last season's growth and turning the soil over.

I could go the Charles Dowding "no-dig" route and heavily mulch with manure, leaving the worms to do the soil improvement over the winter, but I remember from last autumn that the foxes here are so deeply eroticised by the tang of horse poo that they repeatedly roll all over it, wrecking neatly-made beds. Plus I want to be outdoors doing something constructive on the few sunny days that November can offer.

With a heavy clay, what you need to do is open up the soil by adding different ingredients. The green-eyed Irishman has gone for loads of manure and gravel in bags from the local Wickes. I'm going for sharp sand, plus something to enrich and structure the soil.

In the end, I choose cocoa mulch soil conditioner and chicken-manure pellets to go with the sharp sand. I don't want to make cement, so I mix all the ingredients together before adding them to the clay.

The amazing thing is to see how quickly my magic mix makes a difference. The gritty sand and cocoa begins to give the muddy clay some structure. And this technique works for other soils too. For soil that's too sandy, up the manure component; for soils that are too heavy, mix in something drier such as my magic mix, or composted bark.

I can already see that my soil is airier, lighter and easier to till. After four hours of work I have born-again beds full of lovely crumbly soil I can actually dig. Best of all, the rotten cardboard that covers half of my allotment is carpeted underneath with baby worms – some pioneer citizens for my brave new world.

Rich rewards: A few loam truths

1. Mix it in

All kinds of stuff can be used to make a soil better. Manure is best but think also of straw, woodchips, sawdust or bark chippings. Lakeland Gold is bracken mixed with farmyard manure.

£14.25 for 40 litres from Organic Gardening Catalogue, www.organiccatalogue.com

2. Watch your nitrogen

You may need to use fertiliser if you add straw or woodchips. This prevents the soil microbes leaching nitrogen from the plants. Alternatively, use Strulch, a mulch which contains natural minerals.

£19.55 for 200 litres, from Organic Gardening Catalogue

3. Sow a green manure

It’s also not too late to scatter some nitrogen-fixing winter field beans.

£4.25 for 250g from Nicky’s, www.nickys-nursery.co.uk

Read ‘A Nice Green Leaf’, Emma Townshend’s blog, at blogs.independent.co.uk/independent/a_nice_green_leaf/