Buying Seeds and Seedlings
One of the easiest ways to buy seeds is to visit your local garden centre or DIY store, although you may find that the range of seeds that they stock might be limited. Alternatively, you can choose your seeds from a seed catalogue, which will give you a much greater variety of choice. Many of the major seed companies now operate online, so you can browse and order your seeds from the comfort of your armchair.
F1 (first generation) and F2 (second generation) hybrid seeds are available for many plants; these seeds are much more expensive than open-pollinated versions, but produce plants that are vigorous and true to type with even growth and flower characteristics.
F1 hybrids come from two pure-breeding parents that produce offspring which have particular positive characteristics, such as uniform size and shape and vigour. F2 hybrids result from self- or cross-fertilization of F1 hybrids: they are less uniform than their parents.
Whilst some F1 seeds, such as pelargoniums and Brussels sprouts are worth investing in, open-pollinated seeds are quite acceptable for the majority of species grown by most gardeners and will provide some interesting variation in the plants. If you do buy F1 seeds, do bear in mind that you will not be able collect and grow seeds produced by F1 hybrid flowers or vegetables as their offspring will not come true to type.
Always check out the descriptions on seed packets; they are full of useful information about potential difficulties, sowing times, spacings, temperatures, the number of seeds in the packet and the likely number of plants that will be raised from them.
Seeds are often supplied in various different formats to make it easier for the gardener to sow them accurately and easily.
1. Pelleted Seeds
Some F1 and F2 hybrid seeds may be coated with a clay-based paste so that they form a round pellet. This means that they can be handled more easily, so that they can be planted individually in containers or the open ground. As the seeds can be sown at the correct planting distances, the need for thinning is reduced, which means that more viable plants are produced per packet.
Pelleted seeds are usually primed (see below), and so should not normally be stored for more than a year.
2. Primed Seeds
Primed seeds have been pre-treated so that they are ready to germinate as soon as they are sown. This is carried out by exposing the seeds to water so that they swell, and then drying them just as they are about to break out of their coat (i.e. germinate). This has the advantage of improving the germination vigour of the seeds. However, although this is useful for species and cultivars that do not germinate easily, it also shortens the lifespan of these seeds. Any primed seeds should be planted as soon as possible; do not store them for more than a year.
3. Seed Gels
One way to sow seeds evenly is by using a gel kit. Seeds are added to a paste which may be squeezed along a pre-prepared drill. This distributes the seeds evenly so that less thinning is required.
4. Seed Tapes
Seed tapes are tissue paper strips filled with evenly-spaced seeds. The tapes are laid in a shallow drill (6-13mm or 1/4-1/2 in deep), covered with soil and then watered. As the tissue paper becomes moist, it germinates the seeds, then dissolves into the soil. This should result in a line of perfectly spaced seedlings, with no need to thin. They are available in tapes and circles, which may be cut to fit the size of your container.
Seeds are often sold in vacuum-sealed packs; however, they can soon lose their viability if they are left in warm, humid conditions. Store them in a cool and dry place in a tightly-closed tin. You can even keep them in a fridge compartment if they are not to be used for a while.
Always buy fresh seeds that have been stored in cool conditions. Although seeds in sealed foil packets may last for several years, the seed will start to deteriorate as soon as the packet is opened.
Some seeds, such as begonias, can be difficult for the amateur gardener to germinate, and may be bought at the stage when the seed has developed at least one pair of true leaves and is ready for pricking out. Other plants may be bought at an even earlier stage (the chitting stage), just as the seed coat has burst open and roots and seed leaves are starting to emerge. They are usually supplied on agar jelly, which provides them with enough food and moisture for a few days; transfer them to the right growing conditions as soon as you receive them so that they can continue to develop healthily. You can also obtain plug plants grown in modular trays (often known as 'plantlets').
Seedlings usually come in batches of 100 and need to be pricked out into trays and then later into pots before being planted out. Plugs, in 35s, need to be potted on and kept under glass until they are hardened-off.