Half-Hardy Plants
| Published: 6th June 2007 19:16 |
Half-Hardy Plants Propagated by Seed
New entrants to gardening may find propagating half-hardy plants - those susceptible to damage by frost - by seed both productive and exciting. The process need not be daunting, however, if procedures are followed.
What are half-hardy plants?
Bedding plants include the following:
Salvias, Antirrhinums, French Marigolds, African Marigolds, Petunias, Pelargoniums, Begonias and Impatiens (Busy Lizzies)
Vegetables and salad crops include the following:
Runner Beans, Sweetcorn, Tomatoes, Courgettes, Marrows, Peppers and Aubergines.
Seeds of half-hardy plants may be obtained from plants in the garden or pots after the flowers have been pollinated by bees or purchased in packets from the seed merchants. Bear in mind that seed collected from existing plants may not come true to type or be viable - that is able to germinate.
Photo: Martin Horne ^ Timing is important in the sowing of half-hardy plants. Sow too early and the plants may become ‘etiolated', that is long and ‘leggy', reaching towards limited light levels. Sow too late and the plants' growth may be stunted. Follow directions on seed packets, seed catalogues or books on the subject.
Commence by filling a seed tray or pot with compost and firm the compost gently with a pressing board or tamping tool. Sow the seed evenly over the compost. With fine seed, mix it with horticultural sand to spread the seed. It is not essential to sow all seeds, as often there are several contained in the packet, more than needed. Save the remaining seeds for future sowings.
Photo: Martin Horne ^ Some seeds require covering whilst others may sown on top of the compost and left in the light. Follow directions carefully. If seeds need covering, it is possible to cover the plants with sieved compost or alternatively vermiculite, an inert material derived from volcanic matter. The use of vermiculite assists with maintaining warmth, rather like a continental quilt, and reducing the possibility of a process called ‘damping-off'- the onset of rotting on young seedlings.
Photo: Martin Horne ^ After the seeds have been sown, moisten the compost by immersing the tray or pot in a tray or saucer of water. It then helps to cover the tray or pot with glass or clear plastic and, if there is a possibility of strong sun, a page of newspaper. Place the tray or pot into a warm environment. This could be a heated greenhouse, a plant propagator or even the kitchen windowsill. Check the containers regularly for emerging seedlings and monitor the seedlings' growth.
Photo: Martin Horne ^ When seedlings have grown sufficiently and are beginning to become crowded in the container it is time to undergo the process of ‘pricking out'. This involves separating the seedlings and placing them into a new container to grow on in greater space. Lift the seedlings carefully by the leaf - never by the stem, as this could damage the young plant - with a dibber or an old kitchen fork. Always ensure that the compost is sufficiently moist to ensure that there is minimal damage to the plantlet's roots. As the plant continues to grow, it may be necessary to plant them on again into larger containers such as pots to accommodate their growth.
Photo: Martin Horne ^ As the weeks pass, the cells in young plants need to become acclimatised to outside conditions, a process known as ‘hardening-off'. Having transferred the plants carefully from the greenhouse to a cold frame, keep the lid of the cold frame shut initially, gradually more open until eventually the plants are virtually open to the elements and ready to be planted into open ground. Planting out times depend on climatic conditions, so generally the process may be undertaken earlier further south in this country but maybe as late as June in northern England and Scotland.
♥Photo: Martin Horne
♥Photo: Martin Horne
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Photo: Martin Horne ^ Growing plants from seed is one of the most satisfying and rewarding occupations.
Good luck
Martin Horne
