What Is A Seed?

A seed is an incredible feat of packaging; a small plant in embryo form, complete with a food store and all protected by a tough outer skin. Kept dry it will remain dormant but, in most cases, stay alive (remain viable) for one to several years, particularly if stored under cool conditions. When exposed to a favourable combination of moisture and warmth it will usually start to take up water. This causes it to swell which, in turn, results in the skin bursting and allows the embryo plant to start into growth. This process is what is called germination.

Although a few seeds have specialised needs, the following are the basic requirements for success:

• Water - Once sown seeds must be kept moist at all times. Allowing them to dry out before watering again, particularly once they have started to germinate, is a sure recipe for failure. At the same time the soil or compost should never be waterlogged.
• Correct temperature - Seeds vary in the temperature range they prefer for germination. Kept below this they will either germinate very slowly or not at all and may even rot. Kept above they can often remain dormant. Despite these differing requirements, most will germinate very well at a comfortable room temperature, as long as the room is kept warm at night as well as in the day.
• Compost/soil - This needs to be well drained, well aerated and not too rich in fertiliser. For pots and seed trays a wide range of seed and general purpose composts are available. Garden soil is not suitable for this purpose and only fresh compost should be used. In the garden the soil should be thoroughly broken down to a fine 'tilth' and be moist but not too wet.
• Correct sowing depth - A covering of soil or compost helps to keep seeds moist but small seeds with only a very small store of food cannot grow from any great depth and so are best sown at or near the soil surface.
• Light - Most seeds don't require light to actually germinate and are best covered so as to exclude most light until the first seedlings start to appear. A few, such as impatiens and many primulas, do need light and must be sown at or near the surface and not otherwise be covered after sowing.
• Time of sowing - Although the seeds of some short-term crops such as radishes and of various indoor plants can be sown over a considerable period, this is not true of the majority. Due to the seasonality of our climate the sowing time is fairly critical for many, particularly half-hardy annuals and some vegetables, if satisfactory results are to be achieved. For this reason it is most important to stick to the sowing periods indicated in our sowing charts or on our seed packets. Apart from bad germination, poor yields or delayed flowering, sowing at incorrect times can also lead to such problems as running to seed of vegetables ('bolting') and increased incidence of pests or diseases.

Sowing too early can be almost as bad as sowing too late so don't be in too much of a rush to get seeds in, particularly if you don't have ideal conditions for growing the seedlings on indoors or the ground and weather outside are cold and/or wet. The earliest sowing dates given on seed packets are usually for the mildest and most favoured parts of the country only and, for outdoor sowings, it is best to wait until you can feel 'spring is in the air' and the soil is beginning to dry out and feel crumbly.

As long as they are put in within the recommended period, later sowings often catch up and those indoors require much less heat. Later seedlings under glass are also less inclined to become drawn and leggy, less prone to disease and less liable to result in overgrown, pot-bound plants before they can be planted out. Later sowings outdoors usually give by far the best and most reliable germination.

Contents

Introduction
Basic Seed Sowing Sowing Seeds Indoors
Sowing Seeds Directly
Specific Species Advice
Hints and Tips
Possible Problems
Glossary of Terms

The seed contains everything needed to form active vigorous seedlings.


The seed begins by gently swelling, then the root emerges...


Then the shoot emerges shortly after.