Prepare your soil extremely well
When I’m creating a new bed, or cultivating an area for the first time, I like to start by double-digging. This means digging a hole or trench (depending on how big the area is) to a spade’s depth, the soil at the bottom of the trench is then loosened by a fork, and then the trench refilled with the removed soil – or by the soil from the next trench if an entire bed is being prepared and the soil from the first trench then used in the last one. I remove weed roots as I go along. This is hard work, but it should only have to be done once. I find it greatly improves drainage of the soil, helps clear weeds and allows plant roots to grow easily. If soil is compacted plants do not root well.
Alternatively, if you have the luxury of time – or are very sensibly planning ahead – strim any existing growth to ground level and then cover for at least 6 months – and up to 2 years. Unlaminated cardboard is excellent for this as it will rot down over time – as will any vegetation beneath it. Thick layers of newspaper can also work, but any sheet material that will totally block out the light to the soil does the job. Cardboard or newspaper would need to be weighed down
I have been extremely lucky in that the top-soil in most of my garden and my allotment is more than 2 feet (60cm) deep. If however you find that the soil changes colour to orangey brown, white, blue or grey then I’m afraid your topsoil (the living soil) is not so deep. The change in colour means you’ve reached the subsoil – the “dead” soil that does not allow plants to grow. What you need to do here is add lots of organic matter on top of the subsoil before adding any topsoil. Over time worms from your topsoil will feed on the organic matter dragging the subsoil through their guts and turning it into topsoil.
If you decide not to double-dig you must still clear your soil of all weeds, before you can even think of sowing or planting. Diligence at this stage will be amply rewarded later with a much reduced workload. Once you have nice clean soil add a 5cm layer of organic matter – compost or well-rotted manure. There isn’t any need to dig this in; the worms will do that for you.
If time is short or you are impatient to be growing, focus on a small area and get it perfect, and planted up, before moving on.
Raised beds – where the soil is higher than surrounding paths – have better drainage than flat beds and their soil heats up more quickly in spring, helping germination and plant growth. I do recommend them. If you are making raised beds for your vegetables, the simplest and cheapest method is to mark out the beds and paths with canes and string once you have double-dug or cleared an area of weeds, but before you add the layer of organic material. Then use a spade to lift the top 15cm of soil from each path on to the nearest bed. I make my paths 60cm wide – this means I can comfortably weed, water and harvest. If you want to use a wheelbarrow you will need at least some paths to be 90cm wide. The beds can be edged with timber. This looks pretty and helps retain soil in the beds, but it is not essential. Remember to add a 5cm layer of organic matter. The paths can be left as bare earth, covered or paved. The cheapest way to cover the paths is to put down a thick layer of newspapers and then soak thoroughly. Weeds cannot grow through the resulting papier mache layer and it can be made more aesthetic by covering with chipped bark. Alternatively, you can cover your paths with a weed suppressing membrane and gravel. Grass paths are also an option – although they will need regular trimming.
If you are growing in containers use sterile potting media i.e. buy compost. You will get best results from mixing well-rotted manure or home-made compost into the potting media in the lower half of your containers – 20 percent by volume should be sufficient. However, don’t add manure to pots for carrots, parsnips or any of their relatives – they fork in rich soil as their roots search for the additional nutrients.