SEED

Seeds from a good seed firm can be relied on to germinate quickly and well, and it is false economy to buy any but the very best. For outdoor seed beds, prepare the ground well in advance to allow the soil time to settle. Having settled the area required, choose it in a part of the garden or allotment which is well-drained and which receives plenty of sunlight. Manuring is generally unnecessary as very rich soil is not often desirable. It is, however, a good plan to apply a complete fertiliser a few days before sowing. Where sowing in the greenhouse or in a frame, use John Innes Seed Compost which suits most plants. Before sowing all large stones should be removed, the bed brought to a very fine tilth, to ensure an easy root run, and well watered. Thin sowings are usually best and one method with small seeds is to make a hole in the corner of the packet, slightly larger than the seed to be sown, so that the seeds trickle out a few at a time. Another way is to mix them with flour, sand, or dry soil and scatter both along the row. Never sow on a windy day.

The depth at d is sown depends mainly on the size of the seed. Germination failures are often due to sowing so deeply that the young plants are unable to break through; on the other hand, some seeds are liable to dry up if sowing is too shallow. As soon as it is sown the seed should be covered over, cither by raking or by a thin scattering of fine earth. Very small seeds like begonias and carrots need little or no covering, but large seeds, such as peas or beans, should be put in 2—3 in. deep. They often germinate more quickly if soaked in water for 24 hours before sowing.

Ensuring Maximum Germination. Soil-borne fungus diseases often destroy a large number of vegetable seedlings before they appear above ground, particularly on cold, wet soils. Sound seed, correct soil preparation and careful sowing are often largely wasted if diseases like seed decay and prc-emergence damping-off occur. Heavy losses can take place in any weather and vegetable crops, especially peas and beans, may be thinned drastically. Beginners often blame the seedsman when the real cause is disease. A thiram seed dressing can be used before sowing to prevent these losses. Note that this organic sulphur compound is also used as a fungicidal spray for controlling rose rust; see ROSE — Fungus Diseases. It protects seeds from the moment they are placed in the ground, ensuing vigorous growth and high yields for the following crops: peas (tests carried out at one Research Station showed that pea seeds dressed in this way produced 100 % more plants that untreated seeds), runner beans, broad beans, French beans, brassicas, lettuce, marrow, melon, cucumber, spinach, carrot, onion, red beet, radish, mustard and cress, sweet corn. Thiram seed dressings also protect most flowers, ensuring increased germination and preventing damping-off, but germination of some varieties may be affected. It is therefore wise to consult manufacturers’ literature beforehand.

The thiram seed dressing can be obtained in a special plastic puffer pack designed for quick and easy application. The powder is simply puffed into the seed packet which is then shaken vigorously so that the seeds are lightly and evenly coated with the dressing. Note that peas and beans are more readily shaken in a closed tin and because of their larger size will obviously need more dressing.

It is now possible to buy a combined seed dressing specially packed for amateurs. This comprises both an insecticide and fungicide. In addition to protecting against soil-borne diseases, insect pests like carrot fly, flea beetle and wireworm can also be anticipated. For carrot fly and wireworm the dressing is usually also sprinkled thinly in the seed drill before sowing. As with the thiram dressing which is effective against diseases only, manufacturers’ literature should be checked to ascertain any precautions regarding particular crops.

On light land, the soil covering the seed may be firmed by treading, light rolling, or beating with the back of a spade, in order to give the seedlings a grip and to raise the soil moisture to the rootlets. On heavy land, considerable discretion must be used. The soil should be pressed very gently over the seeds, or compacted a few days later when the surface has become drier.

With seeds that germinate rather slowly (e.g. parsnip, carrot and onion) a few quickly germinating seeds, such as radish or turnip, may be mixed with them. These serve to mark the rows, so that the soil may be hoed and stirred before the main crop seedlings show above ground.

In exposed gardens, some form of shelter should be arranged to protect tender seedlings from wind.

Germination. This is dependent on air, moisture, warmth and ultimately light. The seed absorbs water, swells up, and its coat is eventually burst by the radicle or primary root, which immediately penetrates into the soil. The plumule or primary shoot grows upward, sometimes bearing the cotyledons or primary leaves in the air, although in some plants these remain below the ground.

At germination, and for a short time afterwards, the plant obtains all its food from reserves stored within the seed, so that small seeds, which contain very little nutriment, are rapidly exhausted. It is accordingly most important never to sow seeds too deeply, otherwise the young plants may be unable to reach the surface, or reach it in such a weakened condition that they easily succumb to drought and disease, so it is often advisable to have some quick-acting fertiliser present in the soil for the seedlings to use immediately they begin to become independent. This helps to tide them over the danger period, and encourages rapid growth so that they can outgrow the risk of attack by soil fungi, or quickly recover from the depredations of insect pests.

When the seedlings are well through, the soil surface should be lightly stirred between the rows to prevent evaporation and keep the moisture at root level. Hard-coated seeds usually keep their power of germination longer than soft seeds which germinate very quickly. The seeds of lupins, cannas and certain sweet pea varieties, especially the maroons and crimsons, should have their coats chipped with a penknife, as they are relatively impervious to moisture and germination may be irregular unless this precaution is adopted.

Thinning. As soon as the seedlings are strong enough to handle, that is, when they are in their first or second rough leaf, the weakest plants should be removed, leaving the more vigorous a few inches apart. This can also be done in two operations, as leaving the seedlings about twice as thick as they should be eventually will allow for any ‘misses’. The second thinning is then undertaken 2—3 weeks later. Thinning is necessary in order that the plants may have room to develop and extend to their full dimensions. They thus get plenty of light, air, and room for root formation, which enables them to obtain all the moisture and plant food they require. Overcrowding gives rise to weak, ‘leggy’ plants that never give satisfactory crops.

Tables giving average thinning distances for the various crops are often found in gardening books and periodicals, but these figures need not be slavishly followed; it is far more important to have a row of good, sturdy plants, even if the intervals are irregular, than to have a row of nondescripts at exactly the same distance apart. A strong plant should always be left if it is a reasonable distance from its neighbour.

Transplanting:

Plants raised from seed under glass, or in a frame, should be well hardened off before removal, or the exposure to wind and sun in the open garden may prove too much for them. The ground to receive them should be in fine tilth, deeply worked, and freshly stirred. If the soil appears dry it should be thoroughly soaked with water and a dressing of good, rich compost laid on the top. The water will then rise from below and concentrate round the roots of the newly-inserted plants. The best time to transplant is in dull, cloudy, or showery weather. If the seed bed containing the plants to be lifted is thoroughly soaked with water the day before the transplanting is done, the delicate plants, when loosened with a fork, will draw easily, with rootlets undamaged. Leave a small ball of soil adhering to the roots when lifted from the seed bed, as the check to growth is then neither so serious nor so prolonged. Seedlings of border plants should be transferred to nursery beds as soon as they can safely be handled, set out 4—6 in. apart on moist soil, and left there until the proper time for planting out.

Seed Saving:

Keep an eye on the sturdiest plants, not of necessity the largest, but those growing robusdy, free from disease or insect attack, and with flowers producing the finest blossom. Tie one or more spikes or trusses with white tape for later recognition, and when the seed forms pick some so that the rest can develop fully. When mature pick off, shake into an envelope or dry in sun till ready for shaking. Store in shallow cardboard boxes, or matchboxes, and complete the drying under cover, but where sun penetrates, such as on a greenhouse shelf, or in a room by the window. Before storing, but when quite dry, shake to and fro in folded newspaper to polish and remove dust. The amateur will generally find it easier to buy his requirements, especially with vegetables; it needs skill to recognise fully ripe seed of certain plants and in wet weather runner or French beans are very difficult to ripen properly, but the seed of delphiniums, lupins etc. could well be experimented with.

Viability (power to germinate) of Seed:

This varies. Some will still grow well in the third year from buying; others will do no good a year after purchase. For example, willow seeds only retain their viability for a few years. Generally speaking, plants with hard seed coats such as peas are the longest-keeping. Amateurs can easily test seeds for germination by placing them on a moist blotting paper or flannel. Lay on a plate or dish and keep moist. Any living room with a minimum temperature of 50 degrees F. is suitable.

The cost of new seed each season is little and the disappointment of old seed failing is as great as the wasted labour. When purchasing seed make sure it is of the current year; packets often have the year when put up stamped thereon. Note that refrigerated seed of delphiniums is available, a great boon to amateurs as delphinium seed loses its viability rather quickly.

Sterilised Soil:

The ideal seed bed, as outlined by the John Innes Horticultural Institute is built up with sterilised medium loam. Ideally such loam should be steam-sterilised at a temperature of 200 degrees F. for 20 minutes. Although it is much simpler to buy the John Innes Seed Compost in small or large quantities from horticultural sundriesmen etc., some amateurs like to sterilise the loam themselves (it should have apH. of 6.5, I.e. slightly acid, if possible). First make up the loam to a suitable fineness, then dry in the sun. Boil up /2 in. of water in a saucepan and into it put the dried soil, and continue the heat for a short time; the escaping steam thoroughly sterilises the soil. Larger quantities can be done in a copper or metal drum, using 2 in. of water, and putting the soil into a sack, which is suspended in the copper to steam for half an hour. When cool, mix with it 1 part by loose bulk of peat (fibrous or granular) and 1 part by loose bulk of coarse, sharp sand to every 2 parts of loam. This makes an excellent sowing compost; then thoroughly mix with every bushel, 1 ½ oz. (6 teaspoonfuls) of superphosphate of lime and ¾ oz. (4 teaspoonfuls) of chalk finely ground. A rough and ready measure is that a bushel equals 4 fillings of the average pail. If the seed bed is not being used at once, delay putting in the phosphate and chalk till just before sowing. The actual bed can occupy a corner of the greenhouse staging or be laid in the open with a wood or stone surround to distinguish it.

Where sterilisation is not resorted to, trouble can be lessened by mixing silver sand with the seed when sowing, thus securing more effectual evaporation during the seedling period.

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