Soil Preparation and Outdoor Vegetable Sowing

Soil cultivation

Soil cultivation or digging may seem like hard work but, if you take it slowly, it can be a great exercise.

Soil cultivation (or digging) is often carried out to bury weeds and debris which adds organic matter to the soil

Cultivation improves soil structure by alleviating compaction, plus it offers the chance to apply fertiliser, manure and lime. Once initially prepared only minimum cultivation is needed because over-cultivating can damage the soil structure leading to large lumps or compaction.

Digging is called 'primary cultivation' (and can also be carried out by a mechanical rotavator). This is followed by secondary cultivation to produce a fine seedbed, ready for sowing seed or planting.

When to cultivate

Clay soils:

Clay soil. It is dense and slightly sticky, made of fine clay particles, and can be heavy and difficult to dig, but it is usually fertile and holds water well. Digging is best carried out in the autumn, but you should avoid carrying out this task when the soil is wet and claggy. Autumn digging allows the frost to break up the soil over the winter, improving the structure.

Light, sandy soils: are best dug in spring. However, digging can be carried out from autumn to spring, as long as the soil is not waterlogged or frozen. Light sandy soils are well drained and digging will lead to moisture loss, so complete it before the warm spring weather arrives.

Preparing the seed bed and Sowing

Once they are established, vegetables are surprisingly easy to grow. But what does establish really mean? It basically means growing strongly, having survived the sowing and planting phases and both phases are very weather dependant.

Mr Brian Knight would always say ‘well sown – half grown’

There are four factors to ensure successful establishment:

1) Prepare your soil

Good soil condition is vital. You should aim for a soil structure that is finely and loosely divided over firm but not compacted ground. Loosen it fully with a spade, fork or cultivator, then tread over it to break up lumps and rake it so it’s level and fine.

For clay soils, which drain poorly and are slow to dry out, you could try creating a raised bed. In its simplest form the soil in it is simply raked up from the ‘paths’ around it, but it can be easier to maintain with timber surrounds and infilled with some loamy soil. You could also try the no-dig method of sowing seeds into compost that is spread on the soil surface.

Young seedlings are very useful for clay soils because they are half grown.

Seeds do not like wet soil so It’s important to wait for the soil to dry out a little after winter rains to reduce seed mortality. In particularly bad seasons it is worth considering hastening dry conditions by covering the soil with cloches or a clear plastic sheet before sowing seed.

2)Timing is Key

Sow early to make the best of the growing season. If an early-sown crop fails, you’ll have time to sow a second batch. Repeated sowing of certain varieties is necessary in most years, because you want your seeds to get the best possible start.

3) Make sure you sow enough seed

You never get 100% viable seeds in any packet and sowing too few plants is a common mistake.

Seed losses are generally higher earlier in the season but improve following a later June sowing when the soil is much warmer and emergence of the seedlings more rapid.

Use your judgement, sowing thickly where heavy losses are anticipated, most seedlings can be thinned out later.

A useful tip is to use two or more packets of different cultivars for each crop. That way if one seed packet fails the other will normally be successful.

4) Watch out for checks in growth and competition.

Fertiliser gets seedlings swiftly away, but don’t overdo it – excess fertiliser can reduce germination. Hoeing as soon as seedlings become visible prevents competition from weeds