Get Started Early By Sowing Seeds Indoors

Many of the plants that fill our gardens through the summer, including outdoor varieties of tender vegetables and a few herbs, are not frost hardy and require a longer growing season than would be possible if their seeds were not sown until conditions outside were suitable for germination. For this reason their seeds need to be sown indoors in a greenhouse or conservatory, on a windowsill or, in some cases, in a cold frame. True indoor and greenhouse plants are, of course, also sown 'under glass' as are some hardy annuals, perennials and vegetables where an early start is desirable.

As young seedlings are very fragile and, in the first days after germination, vulnerable to disease, cleanliness is all important. All pots, trays, propagators, labels etc., if not new, should be well scrubbed, using a garden disinfectant, and then thoroughly rinsed.

Compost and containers - For almost all seeds not sown directly in the garden a moist peat-based or other soilless seed sowing compost is recommended. General purpose composts can also be used although it may be necessary to sieve out larger lumps. John Innes seed compost is preferred by some, is best for a small number of seeds which take a long time to germinate and has the advantage of being sterilised. Compost brought in from outside on a cold day should be given time to warm up before being used.

Most seeds are sown in seed trays or small plastic pots or half pots although other clean plastic containers can be used as long as they are provided with drainage holes. It is better not to use larger sized normal pots as the seedlings are not in them long enough to need the extra depth. For sowing larger seeds a variety of plug trays, cell inserts which fit inside seed trays and extra deep cells called rootrainers are now available.

Cubes of a fibrous material known as stone wool and plugs of peat/coir mix called Jiffy7s can also be used. All of these allow seedlings to be later transplanted without root disturbance and are ideal for seedlings, such as sweet peas and runner beans, which quickly develop deep root systems. Fill the tray or pot you are going to use to the rim and sweep off any surplus with your hand or a suitable implement such as a large label. Then tap it sharply on the bench or table to settle the compost and give a final gentle firming with the bottom of another tray or pot. This should leave a large enough gap at the top of the tray or pot that it will not be filled completely to the rim even after any covering of the seed has been carried out. It is important not to over-firm, though, as compost which is too compacted may not drain sufficiently and may make it more difficult for seedling roots to penetrate.

Sowing - After filling, trays and pots should be watered well. The best way to do this is from the bottom so stand them in about an inch of tap water and leave them until the surface is wet. Then remove them and allow to drain for at least half an hour. Now sow the seeds thinly and evenly over the surface. Larger seeds can be sown one per cell in plug trays, cell inserts etc., or in individual small pots. If they are not sown thinly the resulting seedlings will be overcrowded and will grow poorly due to being in competition with each other. They will also be more difficult to transplant and more prone to disease problems.

Large seeds can easily be positioned with the fingers but small ones are more of a challenge and various seed sowing devices are now on the market to assist with this task. In the absence of such a device, the end of a damp matchstick can be used to pick up and position individual seeds. Alternatively, a simple but very effective aid to scattering small seeds in a controlled fashion can be made by folding a stiff sheet of paper to form a groove. The seeds are tipped into this groove and the paper is then inclined and tapped gently and repeatedly to dispense the seed. Even when using such a sowing aid, it is easier to sow and see where you have sown very small seeds if they are first mixed with a carrier such as fine dry sand. As soon as the seeds have been distributed on the compost, very fine ones should be pressed gently into the surface but otherwise left exposed. Seeds which require light should be treated similarly or (larger ones) can be covered with a thin layer of seed sowing grade vermiculite which lets light through.

Contents

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

Fill the container and scrape off any surplus soil.


Carefully sow the seed sparingly into a pot or container.


Use a cup or pot to firm the seed into the surface of the soil.


Use a sieve or other tool to lightly dust fine soil over the top of the container.