how to layout a vegetable garden

With your bit of garden cleared and ready for a mini vegetable patch (see starting a vegetable garden from scratch), it's time to lay out your plot and create a structure that looks good and produces delicious food.

Even a small patch should be divided into four areas, ideally four quadrants with a cross of paths, with a small, round central bed if you have the space in which you could grow a tepee of sweet peas. The four beds are then allocated to different plant groups: one for roots, subdivided between new potatoes, beetroot and carrots (the three most rewarding and delicious roots); one for things like beans and peas (which gardeners call legumes); one for salad and herbs, including the brassicas (which means cabbage relatives), rocket, mizuna, mustard and radishes; one for a hotchpotch of things such as courgettes, sweetcorn and leafy greens, chard, kale and spinach.

You can then rotate your productive plants from one year and one area to another, avoiding putting the same plant into the same soil again for four years and hence preventing a build-up of pests and diseases.

Make the beds as big as possible and the paths can be temporary trodden earth or shingle, or permanent brick or stone. They should be a minimum of 30in wide. Anything narrower will be obliterated as plants grow. If you have the space, the wider the paths the better. Perennial plants such as mint, horseradish, rhubarb and tarragon, and the shrubs rosemary, sage and bay, go permanently into any edge beds if you have space there. Beware, mint and horseradish are very invasive and their roots quickly romp away, so enclose them in a deep, submerged pot. Tomatoes and cucumbers can be grown in pots, or in the ground against a sunny, sheltered south or west-facing wall, or in a greenhouse if you have one.

The more space overall you can give to your veg patch, the more variety and abundance you'll produce. It's rare for someone to think their patch is too big, but be realistic in terms of time and maintenance. You'll need a couple of hours a week from March until August – the busiest months – to keep a 10ft x 13ft patch sown, planted up, picked and looking pristine. One final thing on the design – draw out the basic plan on a sheet of paper with a thick black pen. Then attach a sheet of tracing paper over the design so that you can record exactly what goes where each season.

In the late summer, you'll be doing another planting and need to record that on another sheet of tracing paper which can be attached over the top of the last – it's a good idea to do this every year as a belt and braces way of avoiding planting anything in the same spot in under four years.

raised beds or not?

Once you have a layout planned that suits your garden, you need to work on your soil, so find out what raw material you have before you start. For a perfect patch the soil should be freely drained, with plenty of organic material mixed in and a topsoil depth of about 1ft. Some edible plants do fine without much fertility – carrots, for example, grow well in almost pure sand – but most do best in well-fed, rich soil that is well drained.

If you have no idea what your soil is, dig a 17in-wide, 17in-deep soil profile pit – a smart name for a straight-sided hole. This tells you a huge amount. Look at the sides and the colour change as the pit goes deeper. Is there lots of rich black stuff and then a change to something different? Measure how much of the darker stuff you have. This is your topsoil depth. On chalk or sand, and often on clay, this can be very thin.

If your topsoil is thin, this may mean building raised beds, a decision best made before you start your soil improvement programme. We need these on seriously vile and heavy clay at Perch Hill to help with topsoil depth and drainage; raised beds are also invaluable for deepening thin topsoil on sand and chalk. We've also found slugs and snails are less of a problem in our raised areas than they are on flat ground and the beds look ornamental. You can raise the bed with railway sleepers to make a horizontal frame, or use woven panels of chunky hazel or willow as we do. They don't last as long as solid wood (about five years) but look good.

Get the edges in place and then dig out the topsoil from paths and place it on your beds. This may be enough to fill them, but if not you'll need to import some soil. Try to use a different soil type to your own, a hybrid is ideal.

know your soil type

You may already know what your soil type is – if you can see chalk lumps, then clearly it's chalk – but if not, you need to work this out. Pick up a handful and feel it. If it's slimy and you can make it into a ball without it collapsing, it's clay. If at the other extreme, it feels gritty and won't stick together, its basis is sand.

Pour a bucket of water into the soil profile pit. Does it drain away almost immediately? If it does, you have freely drained sand or chalk. If the water sits there, it's almost certainly clay. Also do a pH test with a kit from the garden centre or send off a soil sample to the RHS for analysis. This will help establish your soil base line.

soil preparation

Once you've got that clear, you can start your soil improvement. Tempting though it is, don't just whack your seeds straight in. If you haven't cultivated your plot before, the soil will need a bit of work. Veg need a loving environment: light, airy and full of goodness. Rather than sowing or planting into lumps like boulders, a small soil-lump-size is crucial for happy and abundant plant growth.

For clay without a decent topsoil depth, dig in lots of grit and organic matter. This is likely to mean large quantities, rather than one or two bags from the garden centre. The grit I use is 9mm pea shingle from a builder's yard (rather than the more expensive horticultural grit). This is the smallest stuff for putting on a drive and it does the job well. For organic matter, I use municipal compost (widely available from local councils composting kitchen waste). Cover the whole soil surface with 2½in of grit and 2½in of organic matter before you dig (or rotavate) it in. You can hire a rotavator for a morning. This will convert a ropey topsoil into something instantly good.

If you garden on light sandy or chalky soil, dig in lots of organic matter to help the plants grow well, but leave out any extra grit. On chalk, try to avoid disturbing the subsoil – or endless flints will rise to the surface and you'll have to spend hours getting rid of them. You may be better off importing almost all the soil so you can get cracking.

the ornamental patch

If you're short of space, you'll have to concentrate on the easy and highly productive plants (more about this next week), and won't have the luxury of being able to make the garden look beautiful as well as produce food, but if you have more room, you can.

Create a high point at the middle of each bed. Put up a tepee made from eight bamboo canes or twiggy sticks and plant two sweet pea seedlings at the foot of each stick, or just create a tall central patch of some beautiful rich-coloured dahlias, such as the dark crimson, 'Rip City', 'Chat Noir' or 'Bishop of Auckland'. If you keep picking the flowers for the house, these will look good for months.

If you have plenty of space, you can also edge your paths with flowers, selecting plants that have a beneficial effect on your productive garden. Any yellow or orange flower – the poached egg plant (Limnanthes douglasii) and marigolds (Calendula 'Indian Prince') in particular – attract beneficial insects, lacewings and lady birds. If you draw a good population in, they will lay their eggs within the patch which then hatch into larvae. These love aphids and should keep your patch free of green and whitefly.