development of the young plants. This is " known as pricking out or potting on. | f ill a container with John Innes No. 1 A compost or a compost of similar structure r , (see page 12), and firm to the base with the k tips of the fingers. Strike off compost level r with the rim. Lightly firm with presser board ) so that the compost is in below the rim . of the container, which is now prepared. f Water the seedlings; then loosen them by ^ knocking the old container so that the compost comes away from the sides. Hold a ) seedling by its seed leaf and gently lift with ' the aid of a dibber, keeping its root system * intact. Never hold the seedling by its stem, t With the dibber, make a hole in the fresh ^ compost big enough to take the roots. Drop I in the seedling and gently firm the compost j back round the roots with the dibber. Repeat this operation for each seedling, spacing ) at 24-40 seedlings per tray.
After the tray has been filled, water in the ^ seedlings and return them to the warm en-^ vironment (21°C/70°F) so that they can re-• establish as quickly as possible.
After the seedlings have been pricked out, they have to be gradually weaned to a stage at which they can be planted out and survive cool temperatures, fluctuating water conditions and the effects of wind without their growth rate being affected. In the plant world this process is generally referred to as hardening off.
Most seedlings will have been germinated in a protected environment during the early part of the year to produce a plant of sufficient size to be planted out as soon as the danger of frost is passed. Because so many seedlings are produced in the early part of the year, and they are not hardy, and in most gardens there is a premium on any space that provides sufficient protection, plants tend to be grown at a high density.
The problem with crowding plants together is that an increase in fungal diseases both on the stems and leaves and in the compost is likely to result; the plants tend to become spindly as they compete for light; and the varying plants have different watering needs
7 Hold the seedling in one hand. Make a hole with the dibber in the fresh compost in a pew container.
8 Place the seedling in the hole and firm the compost back with the dibber.
9 Water in the seedlings once the seed tray is completed. Place in a warm (21°C/70°F) area.
so more day-to-day care and attention are needed, which is of course time consuming.
Once the pricked-out seedlings have reestablished, move them to a cooler environment. For this purpose there is no real substitute for a cold frame, which should be kept firmly closed. Over the course of a few weeks increasingly air the frame during the day by raising the lid, until the frame is continually aired during the day and night: indeed the lid may be completely removed during the day if it is warm. Eventually the lid can be discarded altogether.
Frosts as severe as — 4°C/25°F are sufficient to penetrate into the cold frame, so, if this level of cold is expected, provide some insulation to protect half-hardy plants. The best and most easily manageable insulation should be light yet thick; coir matting and similar materials are useful and effective.
Regularly check the seedlings in the frame to ensure that they are not drying out excessively. They should not however receive too much water. If anything it is better to err on the side of dryness rather than risk water logging. Under these cooler conditions wet composts are increasingly susceptible to fungal root rots. Similarly, the close density of plants creates conditions under which leaf diseases are capable of taking hold. It is, therefore, important that all plants in the frame are sprayed regularly with a fungicide, either Captan, which will prevent the diseases spreading, or a systemic fungicide such as Benlate, which should prevent an outbreak of the diseases.
Another aspect of seedling management is the necessity for feeding. Many pricked-out seedlings will spend several weeks in the potting compost before being finally transplanted, and there is no point in starving them and preventing them developing to an adequate size. Thus the seedlings should be regularly fed using a proprietary liquid fertilizer at the intervals stated on the manufacturer's instructions. Avoid excessive feeding as it will produce over-vigorous plants that will check their growth on transplanting; it will also increase the risk of disease in the cold frame.
10 Cover cold frame with coir matting to insulate seedlings against damage caused by frost radiation.
11 Raise the cold frame lid to allow the seedlings to harden off.
12 Water, using a fine rose, to ensure seedlings do not dry out. Add a fungicide and liquid feed regularly.
Was this article helpful?