Sowing outdoors

Before you sow

Clearing the site

Fork over the soil two or three weeks before sowing to encourage the weed seeds in the soil to germinate. They can then be hoed off before sowing crops. Remove the first flush of weeds. This will mean seedlings won't be competing with weeds for light, water and space.

Preparing the seedbed

Choose a day when the soil is dry enough not to stick to your boots. If it hasn't been settled by rain, tread over the area to firm it down. Scatter a general purpose fertiliser over the soil and rake until the ground is level, removing any large stones or debris. This produces the ideal surface for sowing. Add plenty of organic matter such as compost.

Warming the soil

If sowing when the ground is still cold and wet after winter, cover the soil for a few weeks first. In addition to warming the soil, this also helps to dry out the surface, which makes it workable for seed sowing. Use horticultural fleece or a plastic sheet to cover the ground. Once the seed has been sown, these should be removed so that they don't damage the emerging seedlings.

Alternatively, a cloche can be used. It can be left in place after sowing because the emerging seedlings will have plenty of space beneath it. Plants grow quickly in these protected conditions and mature before those sown in open ground. Water plants under the cloches as the soil can become quite dry. Ventilation is also vital because still air can create the perfect conditions for fungal diseases.

What to do

Sowing in drills

• Sowing in drills is the most commonly used method for outdoors. First, make a shallow V-shaped seed drill using a draw hoe or cane, following a straight garden line as a guide.

• Water along the length of the seed drill, using a can without a rose, to create the damp conditions that seeds need to germinate. Annuals can be sown in drills within an informal outline.

• Carefully sow the seeds along the drill so they're evenly spaced and won't be overcrowded when they germinate. The row of seedlings will be easy to distinguish from emerging weeds.

• Use a hoe to draw dry soil back over the drill, completely covering the seeds. Then firm the surface by pressing down the soil with the back of the hoe. Finally, label the row.

Broadcast sowing

For covering large areas such as lawns, use broadcast sowing. The informal effect is also well suited to creating drifts of colourful hardy annuals.

• Mark out the areas to be sown using silver sand. This will give you an idea of the final effect and allow any changes to be made before the seed is actually sown.

• Make sure that you scatter the seed thinly so that the emerging seedlings will evenly cover the whole area and won't be overcrowded when they germinate.

• Lightly rake over the entire area at right angles so that the seed settles into the soil surface, then water the area in with a watering can fitted with a fine rose.

Aftercare

Thin seedlings as soon as they're large enough to handle.

• Choose a mild day when the soil is moist and aim to retain the sturdiest seedlings whilst keeping spacing even. If the weather is dry, thoroughly water seedlings a few hours before thinning. This minimises root disturbance and makes it easier to pull them out.
• Select the plant you wish to keep, put fingers on either side of it to steady the soil around its roots, then gently remove all the surrounding unwanted seedlings.

• The spare seedlings of most plants can then be transplanted to fill out any gaps elsewhere. Some plants such as clarkia dislike disturbance, so they're best thinned out to their final spacing, discarding the excess seedlings.
• Never leave unwanted seedlings lying on the ground as this can attract pests and diseases.

Treated seeds

To make germination more reliable, some seeds may be coated with a chemical dressing. This usually contains a fungicide to help prevent the seeds rotting. Occasionally, an insecticide is also added to protect the seedlings from pests.

Priming

Another method to improve reliability is priming. Give the seed a limited amount of water to start off the germination process and ensure that all the seeds are at the same stage of development at the same time. Primed seeds germinate more evenly and quickly, and often at a lower temperatures, making them useful for early sowings.

Due to the expense of this method, it's only available for a limited number of plants such as carrots and parsnips.

Easy sowing

The seed of popular varieties is often available in forms that can make sowing even easier. The following two types are useful for anyone who has difficulty handling smaller seeds.

Pelleted seed is covered with a soluble coating that makes it easy to handle and space out evenly. Thorough watering after sowing is essential to ensure the moisture needed for germination penetrates the coating quickly.

Seed tapes are becoming more widely available. These strips have seeds embedded in them at regular intervals, so they don't need thinning out later. Simply lay the seed tape in a seed drill and cover it with soil, making sure it's in full contact with the ground.