Organic Gardening

DEPTH AND DISTANCE

There is no doubt that the main cause of seeds failing to germinate is that they are sown too deeply. Seeds have a reserve of food which will enable the shoot to reach the surface and find the light. Until it does this, it cannot manufacture any more food. So, if the seed's reserve runs out before the shoot reaches the surface, the seedling will never appear. Of course, it is nonsense to suggest sowing seeds 6mm (1/4in) deep or less, since it is impossible to be that accurate when working with soil.

It is also important to space the seeds and drills correctly to avoid overcrowding. Some seeds can be thinned and transplanted later, others, such as those of root crops, will "fork" if transplanted.

TECHNIQUES

Always aim to sow seed thinly. With the vast majority of seed varieties, between 60 and 90 per cent of your seeds will germinate and, if they come up too thickly, they tend to compete for the available light, becoming thin and straggly in the process. Some gardeners become adept at sowing straight from the packet, but I find it much more accurate to hold the seeds in the palm of my hand and sow a pinch at a time.

Some seeds are large enough to sow singly or in "stations" (placing groups of two or three seeds at the required distances, then thinning if more than one seed germinates at any station). With deep beds you should adopt a block-sowing technique.

Sowing in dry soil: If your soil is very dry, water the drills before sowing. Use a can, more or less fill up the drill, allow the water to drain, then sow as directed. Never sow and then water afterwards, since this leads to "capping", where the soil forms a crust on top that can prevent the entry of further water or even prevent young seedlings breaking through to the light. Covering after sowing Cover all seeds by running the back of your rake down the center of the row. Then, lightly tap down the soil with the back of the rake to ensure that the seed is in close contact with the soil.

Labelling rows of seeds: Always use a proprietary plant label to mark the row clearly with the name of the plants. It is not good enough just to stick the seed packet on to a cane, as it always seems to blow away or becomes unreadable after heavy rain.

Pre-germinating seeds: Sometimes it is an advantage to pre-germinate seeds inside and sow them outside only after they have started to grow. Examples of plants that benefit from this are parsnips, which take so long to germinate in the early spring that they often rot in the soil, and lettuce, which will not germinate in soil temperatures over 20C (68F), a temperature often reached in summer even in colder areas.

Sow the seeds on to a piece of moistened tissue in the bottom of a plastic container. If the seeds need heat to germinate, place the container in a warm place, such as the airing cupboard, until the first roots show through, and then sow as soon as possible. Do not let the roots grow longer than about 3mm (1/8in). If you cannot sow the seeds immediately, put the container in the refrigerator (not in the freezer compartment), where they can be kept for a few days.

You must sow the seeds without damaging the fragile roots. With large seeds this is not too difficult, since you can pick up each individual seed with tweezers. With small seeds, however, you need to fluid sow them. Suspend them in a special alginate gel or wallpaper paste and "sow" the mixture in a seed drill. If your soil is dry, break the normal rule and water over the top immediately after sowing; otherwise the gel may set too hard and trap the seeds under the soil.