How to sow seeds indoors and outdoors including preparing the soil

As mentioned in our introduction to planting seeds, your chosen container should be clean, sterile and with good drainage.

• Fill your tray, seed pot or container with the compost, and water lightly with the fine rose attachment to your watering can. Leave for 24 hours, so that the compost is moist but not soaking wet.
• Firm the compost down with your fingertips and then level it out so that the surface is completely even, with a piece of flat wood or board.

• Sprinkle the seeds thinly and evenly over the prepared surface, ensuring that the seeds have space around them and are not too clustered together. Larger seeds can be distributed with the fingers, leaving equal gaps in between each seed, whereas smaller seeds will have to be sprinkled with the fingers or tipped out from the packet.
• Cover the seeds with a thin layer of fine compost. Very tiny seeds should not be covered at all, as they may not be able to penetrate the layer of soil when trying to emerge. A general rule of thumb is to cover the seeds with one and a half times their height in soil.
• Flatten the compost firmly but lightly with a board or piece of wood.
• Now, choose one of the following: cover the container with a sheet of glass with a brown piece of paper on top, or place inside a polythene bag secured at the bottom with an elastic band. Any drops of condensation should be wiped away and should be checked daily.
• The seeds should be maintained at a temperature of 60° - 70°F, although this may vary, so check the packet for accurate instructions. Keep in a shady spot until the seedlings have broken through the surface.
• As soon as germination has taken place, the seedlings should be uncovered and moved to a sunny, warm and most importantly, well-lit spot on the windowsill or inside a greenhouse. Seedlings require plenty of light to prevent them from becoming spindly and weak. Also ensure that they are kept moist but never waterlogged or drenched.

The seedlings should be pricked out as soon as two sets of true leaves appear which should be about 4 - 6 weeks after the initial sowing. Discard the weakest seedlings and transfer the healthiest ones to a new tray or container of compost, leaving approximately 2 inches between each seedling. Take extreme care when handling, taking care not to damage the roots. Water afterwards and keep in the shade for 24 - 48 hours.

Hardening off is an extremely important process in the preparation of indoor-raised seedlings and their transferral outdoors. Basically, this is the period when the seedlings are prepared for the harsher outdoor climate and are acclimatised before the move.

First of all, move the seedlings to a cooler room or to a cold frame. This will be followed by several days of being kept outside in daytime hours, before finally leaving the seedlings outside all day and all night for about a week and then transplanting to their eventual outdoor location.

Half-hardy annuals can be sown directly outdoors during the late spring, once the frosts have gone and climatic conditions are correct for germination to take place. There must be a certain amount of moisture, warmth and air for this to happen and if these conditions are not present, it is best to delay sowing for a few weeks or even bring forward sowing if spring arrives early. Note that some annuals may be sown during autumn months, as they will be able to withstand the winter weather.

The first thing to do is to prepare the area where you are going to plant your seeds. Do this when the earth is moist but not soaking wet and a few weeks before planting. Dig the area to a depth of between 8 - 10 inches using a garden fork or spade and work in some fine compost. Remove any weeds and add a little general fertiliser. Rake over the surface of the bed so that a fine tilth is produced, ensuring that there are no big clumps of soil or any stones.

Prepare seed drills using the end of a trowel or hoe. Try to keep the drills as straight as possible. Check the seed packet for the depth of the drill - larger seeds will require deeper drills. The usual rule of thumb is that the seeds will be covered with twice their depth of soil.

Sow the seeds as thinly as possible ensuring that there is space between each one. Cover with the soil previously removed to make the drills, firm down and water. If necessary, mark the drills, stating what has been planted and when. Water the area approximately once a day, if there is no rain, keeping the soil moist at all times.

Within a number of weeks seedlings should begin to sprout through the soil. When two sets of true leaves have appeared on each one, and the seedlings are approximately 1 inch in height, thinning can be carried out.

Remove weaker seedlings leaving a gap of 1 - 2 inches between each plant. Repeat this process about two weeks later. At the same time, pull up any weeds and discard them, although mulching can help with this and will keep weeds to a minimum.