The ground should be thoroughly cleaned, dug, broken down and firmed. The same preparation as that for sowing a lawn is suitable except the soil should not be made quite so firm (see pages 144—5 for how to prepare the ground).
Hardy annuals flower best in ground which is not too rich in plant foods. A general balanced fertilizer can be raked in during preparation if the soil is really hungry, but perhaps the cheapest and easiest method is to water weekly during the growing and flowering period with a high-potash, soluble plant food.
Seed is obtainable in packets from garden centres and garden shops, some supermarkets and general and multiple stores, and by mail order from the seed companies from their annually produced catalogues. A wider selection is usually available by mail order.
Some seed companies even offer ‘package deals’ of seeds for whole borders, and supply well thought-out plans to work to.
In warm parts of the country seed can be sown in early autumn while the soil is still warm enough to germinate it. The hardy annuals will then over-winter as small seedlings. It is best not to thin these too much until the spring to allow for some natural wastage.
In most parts of Britain, and especially if you are in any doubt, it is better to wait until March and April when the air and soil temperatures are getting higher. Short-lived annuals can be sown at any time of the spring and summer to provide a succession of flowers.
Hardy annuals do not transplant well, but if you require more control over their positioning you can sow two or three or a pinch of seeds into individual pots, either outside or in a cold greenhouse for slightly earlier flowering, then the pots are planted out when the young plants, thinned if necessary, are big enough. You should use a good potting compost for this, which increases the cost of the scheme.
method. Mark out the patch to be sown by drawing a line round it in the tilth with a stick. This is not vital if you are just sowing odd groups, but is more or less essential if you are making a whole border out of hardy annuals, so you can see where each type starts and finishes.
Draw shallow drills across the area about half an inch (10 mm) deep. Sow the seed thinly into these. If you cannot sow thinly enough, you can mix the seed with a little sand to make it easier to handle. Alternatively, if you prefer, you can broadcast the seed over the surface.
Rake the area very lightly to cover the seed.
The time taken to germinate varies according to type of plant, time of year and kind of soil, but is usually somewhere between 1 and 3 weeks.
After-care. Keep the soil moist. If you are watering, a fine rose on the watering can is best. Keep the area as free from weeds as possible.
Once the seedlings are showing, thin them out as soon as they can be handled. You might have to thin them out two or three times over a period until the required final spacing is reached. The instructions on the packet will tell you how much space you should leave between seedlings.
As with everything connected with gardening, always read the instructions first!
As soon as you have thinned out enough, you should provide twigs as supports for the plants. Eventually you will not be able to see the twigs as the annuals grow through them, provided you do not make the supports too tall.
For the rest of the season, maintenance consists of a high potash feed as previously described, and some dead heading if you can manage it.
At the end of summer, pull the plants up and put on the compost heap. You can replant the vacant area with spring bedding subjects, bulbs, or permanent plants, or dig it over and leave it to lie fallow till the spring. propagation. Hardy annuals set seed very easily and when this is ripe it can be removed, dried off in an airy place for a day or two, and then stored in airtight containers until required for re-sowing. Plastic margarine tubs are ideal for this. Most hardy annuals come true to type when grown from saved seed.