There are two main planting seasons for short-stay bedding plants (plants which are grown for one seasonal burst of colour and then lifted). Popularly grown summer bedding plants, which flower from early summer to early autumn, are set out in early summer. And spring bedding plants which flower in the main from late winter to late spring are set out in early autumn, while there is still some warmth in the soil. In most gardens spring bedding plants very often go into land vacated by the summer varieties. Incidentally, some so-called spring bedding plants flower intermittently throughout winter in mild areas.
Bedding plants are perhaps the most vulnerable of all ornamentals at planting time. This is largely because the growth is soft and they are set out while in active growth, and in many instances when actually in flower. So extra care is needed.
Ensure the soil is well prepared. Plenty of organic matter should be incorporated during preparations. And the soil needs to be broken down into a fine crumbly tilth by forking or cultivating and raking. Immediately prior to planting, spread and rake in general fertilizer at the rate of a small handful per sqm (yd). Water thoroughly the day before planting, in all but the very wettest of weather. Use a can with a fine rose and apply at least 101 per sq m (2 gal per sqyd), and leave to soak overnight. Similarly, soak all plants thoroughly and leave to drain for about half an hour before disturbing their roots. Most plants are sold in strips of polystyrene. Ease them apart carefully so as not to damage their roots. One good way is to cut the polystyrene and then peel it back bit by bit.
Wallflowers are the one exception. These spring bedding plants are usually sold in bundles with little soil at their roots. Soak them in a bucket of clean water prior to planting.
The cool of the evening is the best time for planting. Use a trowel and take out holes large enough to take the roots comfortably. The soil should be well firmed back around the roots, using the fingers or the handle of the trowel. Water to settle the plants.
Note
Before setting out bedding plants, do check on the ultimate height of the plants. Set tall behind short in front-facing borders. And in beds viewed from all sides, do ensure the tall varieties are centrally placed and surrounded by the more dwarfing kinds.