FRUIT & VEGETABLES 183182 FRUIT & VEGETABLES

PREPARING THE SOILTraditional preparation of soil for growing vegetables includes stripping turf and removing weeds, digging as deeply as possible and incorporating a 5–10cm thick layer of well-rotted manure or garden compost. Preparing clay soil is ideally done in the autumn, so that it is left exposed to frost and rain and is crumbly by spring, but sandy soils can be worked anytime through autumn, winter and spring. Digging like this can be very satisfying and, on sandy or loamy soils, will quickly give you a bed that’s ready to sow into. However, it is back-breaking work, especially on heavy soil, and you may wish to save your strength for other tasks.

To convert weedy ground or turf into growing space without digging, cover it with some cardboard and a 10–20cm layer of garden compost or manure. You’ll find this is easiest if the bed is edged with boards to hold in the compost. The cardboard and mulch will block out the light from any weeds, causing them to die back, but water will still able to permeate through and plants grown in the mulch layer will eventually root down through the cardboard and into the soil below. What you mulch with and how thick the layer is will dictate what you can grow in the first year. Courgettes, pumpkins, squash and potatoes will all be very happy growing in rough compost or rich manure and can easily send their roots down into the soil below. Crops such as carrots and salads, which are sown directly into the bed from seed, will do well only if the mulch layer is very crumbly and well-composted. They also need the mulch layer to be at least 15cm deep, as they may not be able to penetrate the compacted soil beneath. In the second year you should be able to grow whatever you want as the compost will have broken down, the cardboard will have rotted away and worms have begun to amalgamate the mulch and soil layers.

Maintaining the soil structure

Traditionally, vegetable beds are dug each year with another layer of well-rotted manure or garden compost forked in or spread on the surface. Digging allows for the thorough removal of weeds and debris from previous crops and the opportunity to break up clay, but it can also weaken the soil structure and disturb soil micro-organisms. Advocates of a ‘no-dig’ approach believe it is better to simply hand weed as necessary and mulch the surface, leaving the soil beneath undisturbed.

For most gardeners, a mix of techniques makes sense, depending on what type of soil you have, how well established your plot is, the quality and quantity of compost available, and what you’re planning to grow. There is certainly no point in digging soils that are already friable and weed-free. At the very least, digging less often reduces the heartbreak of slicing through earthworms (which – contrary to popular myth – do not regrow). Conversely, sowing seed into a surface layer of rather lumpy garden compost is unlikely to yield great results so, if this is all you have, it may be best to fork the compost into the surface of the soil and use a rake to make a fine tilth.

(For details about making compost, see ‘Looking after the soil’, pp.247–48.)

Green manures

If you can’t produce enough garden compost and don’t have a reliable source of manure, you can improve your soil by growing green manures. These are crops grown on bare ground either in spring or autumn and dug into the soil a few months later, to enrich it and improve the structure. The best, such as crimson clover (Trifolium incarnatum), have the ability to fix nitrogen from the air into nodules on their roots, which is then released into the soil as they break down. It’s wise to cut down and dig in green-manure plants before they set seed, otherwise you may have seedlings appearing next year when you are growing other crops. On clay soils, bear in mind that deep-rooting, over-wintering green manures, such as grazing rye, can be hard work to dig in.

CHOOSING WHAT TO GROWTraditionally, large vegetable plots often include a small fruit tree or two, a few soft-fruit bushes, a patch of raspberries, a strawberry bed, some perennial vegetables such as artichokes or asparagus, and lots of annual vegetables. However, there is no reason to grow this traditional selection of crops: focus your time and space on the things you really want to eat.

Gardeners with small plots could abandon currants and staple crops like potatoes, onions and cabbages, which take up a lot of space and are cheap to buy in the shops. Instead, they could concentrate on prolific cut-and-come-again salads, climbing beans and herbs. People with very little time might consider focusing on low-maintenance crops that yield harvests over several months with minimal effort; autumn-fruiting raspberries, chard and courgettes are good options. Winter squashes are also very useful as they can be stored for many months.

Once you have decided which crops to grow, the choice of varieties is endless. Look for those recommended for flavour, high yields and disease-

CROP ROTATION Crop rotation involves grouping vegetables according to how closely related they are, or how similar their needs are, and planning to grow each group in a different bed each year. Cabbages and all their brassica relations are grown in one bed, for example, while root crops are grouped together as they have broadly similar requirements. This is thought to avoid a build-up of pests and diseases specific to certain crops and ensure plants with different rooting depths and nutrient needs grow in fresh soil each year.

Close adherence to this technique is not necessary in small plots, where most pests and diseases can easily travel a short distance between beds. It is better to focus your planning time on how much room each crop needs, how long it will be in the ground and what can follow it, in order to maximise the space you have. The elements of crop rotation to factor in as your plot develops are that potatoes break up the soil nicely and beans and peas add nitrogen, so it’s good to grow them in different places each year for the benefit of the next crops. Also, if you do find a root disease such as club root on brassicas, don’t grow them in the same spot again for several years.

resistance rather than the largest, firmest or best-looking, which have usually been bred for show or retail. You’ll find many vegetables, including beetroot, carrots and courgettes, come in a wider range of colours than in the shops. When making your choices, it may be useful to know that ‘F1’ after a variety name relates to the plant breeding process and is often an indication of the quality and reliability of the seed. ‘AGM’

p Well-prepared soil in long raised beds.