How to Plant Seeds – Essential Advice
Sowing Seeds and How to Plant Seeds
Sowing seeds is the simplest and cheapest way of raising large numbers of plants, especially annual bedding plants and vegetables.
Seeds are small embryo plants. Most produce plants of uniform appearance, virtually identical to their parents — these are said to be `true to type’. They arise from natural self-pollination or by plant breeders always crossing plants with similar features.
Nowadays, you will often find F1 hybrid seeds offered. These are the result of crossing two pure-bred strains under controlled conditions. They show improved vigour and uniformity, and often make better garden plants. But breeding and production costs increase the retail price.
Annual plants grow rapidly from seed and this is the only successful means of propagation. Most perennials also grow well from seed, though or division are often quicker methods of getting flowering plants.
Shrubs and trees can be grown from seed, but you may have to wait many years for a good-sized plant — for instance, a magnolia grown from seed may be just 1.5m (5ft) high after 10 years. Cuttings will often be a faster method, or you could buy semi-mature plants from a nursery. Bulbs, corms and tubers, too, produce seeds, but offsets or bought bulbs are easier means of increasing your stock.
House plants are often increased by cuttings,or division, but seed-sowing is a perfectly good alternative. Many seedsmen supply house plant seeds nowadays — even some quite exotic types. in particular are successful grown from seed.
How to Plant Seeds – Types of Seeds
Seeds vary greatly in shape and size. They may be as big as a brazil nut or as fine as pepper; some have very hard coats, while others have soft fleshy coats. A few have wings or barbed hooks, which, under natural conditions, assist distribution. These differences largely determine their cultural needs.
Pelleted seeds are also available. Each seed is coated with a decomposable material, making it larger and easier to handle. With precise spacing possible, there’s no need to thin— but the pellet does not improve germination, and can even slow it down.
For yet simpler sowing, buy a seed strip which consists of a roll of tape with seeds stuck to it at precise intervals — bury the whole tape in the seed drill. You can even buy small containers with ready-sown seed in a-less such as vermiculite — you just add water and quite soon seedlings will emerge.
How to Plant Seeds – Sowing Depth
Generally, seeds should be sown at a depth equal to their thickness, although very large seeds can go deeper Small seeds, such as petunias, need only a fine covering of soil. A few, such asand celery, are best left uncovered since light is essential to germination — most seed packets give guidance.
How to Plant Seeds – Raising Seedlings Indoors
It helps a little if you know how to plant seeds, such as half-hardy– these can be raised easily indoors, and, with earlier sowing than is possible outdoors, plants can be brought to flower a few weeks earlier. Sow between late winter and mid spring, according to advice given on the seed packet.
If you use old trays or pots, first scrub them in soapy water or detergent, then rinse thoroughly. Fill them with seed compost, such as John Innes seed/cutting type. (Never use potting composts —they contain fertilizer which burns delicate seedling roots. Multi-purpose composts are suitable, however.) Firm the compost down to 1-1.5cm (¼-1/2in) from the top of the container.
Knowing how to plant seeds is all well and good when you’ve been doing it a while. Take note that they should be sown thinly on the compost — open up the seed packet to make a spout, then, holding it over the compost, tap it on a fingernail of the other hand to produce a slow but steady flow of seeds.
Many suppliers seal seeds in plastic-lined foil sachets for freshness. Tear these open and tip the seeds into your hand, then either tap them off with a finger of the other hand or pinch a few between finger and thumb If seed is very fine, mix it up with a little sand in a saucer before sowing — this makes it easier to see, and so get an even sowing.
Cover large seeds with sieved compost, using a coarse flour sieve, or sprinkle carefully with your hand. Small seeds are best covered with fine silver sand.
Water the compost by standing the tray in water halfway up its sides in a sink or bowl. Remove from the water when the surface of the compost appears wet — most composts darken when moist.
Label the container, using a pencil rather than ink so it doesn’t wash off or fade. Cover with glass or polythene, which must be wiped daily to remove excess condensation. You can also cover with newspaper to prevent a build-up of high temperatures and reduce the amount of condensation.
Stand the container in a warm place at 15-24°C (60-75°F). From a couple of days to three weeks after sowing, seedlings appear — at first generally consisting of a pair of round or oval seed leaves. Remove the cover and move the container to a bright window-sill. As soon as the first true leaves have developed, the seedlings are ready for pricking out.
If you use a propagating frame, there’s no need to cover the seed tray with glass or polythene. Once seedlings appear, remove the top of the propagator during the day to allow a flow of fresh air over the tray — damp, stagnant air promotes damping-off disease.
How to Plant Seeds – Pricking Out Seedlings
Fill a seed tray with moist John Innes potting compost No. 1 or a proprietary potting compost. Firm it in as for. Mark out the planting holes with a small dibber or pencil, spacing them 2.5 — 3.5cm (1 — 1-1/2in) apart each way.
When seedlings have two or three true leaves, thin them out while their roots are still small and removal won’t disturb adjacent wanted seedlings. They come out more easily when soil is moist, so if dry, soak the day beforehand.
Gently lever a small clump of seedlings, with some of their compost, from the container — a plastic plant label makes a useful tool. Hold each seedling by one of its leaves and tease it away from the others. Never handle them by the stem — a damaged collar is invariably fatal.
Pull out each unwanted seedling while pressing down the soil on each side with the fingers of the other hand to hold remaining seedlings firm. Transplant thinnings to a spare area or discard them.
Lower seedlings into their planting holes and firm in the compost around each, again using a dibber or blunt pencil. Don’t damage the roots. Label the tray and water with a fine-rosed can or mist sprayer. Place the tray on a window-sill out of direct sun.
A couple of days later, move the tray to a sunny spot. Keep the compost moist, but not wet.
How to Plant Seeds – Hardening Off
Once established — four to eight weeks after pricking out — harden off young plants. Begin by moving the tray to a sheltered spot outdoors in fine weather, bringing it back indoors at night. After a week or so, leave outside permanently, but protect from harsh weather andat night.
A cold frame is an ideal place to harden off plants. For the first few days, open the frame slightly, during the day only. Increase ventilation gradually, until by late spring the cold frame is completely open.
How to Plant Seeds – Sowing Seeds Outdoors
Alland many , as well as and certain perennials, shrubs and trees, can be propagated from seed sown in the open ground — whether in a seedbed for later transfer, or directly in their flowering/cropping site.
Where soil-borneare a problem, shake seeds up with a proprietary seed dressing before sowing.
How to Plant Seeds – Soil Preparation
Dig the soil in autumn, allowing frosts to break up the clods. For vegetables — except root crops — work in some compost or well-rotted manure.
In spring, as soon as the soil is dry enough not to stick to your shoes, loosen the top 15-20cm (6-8in) with a fork. Apply a good handful of general-purpose fertilizer per sq m/yd, then rake it in. Just before sowing, rake the soil again to get a fine, crumbly tilth. Sowing in a border Prepare a sketch plan of the desired layout in advance — grouping colours and heights according to your own preferences. Mark out the sowing areas with the edge of a hoe or a stick, or with a trail of sand.
Within each sowing area, either sow seeds in grooves — drills — or scatter over the whole surface and rake into the soil — broadcast sowing. With broadcast sowing, though, it’s harder to ensure correct sowing depth and to weed between seedlings later on.
How to Plant Seeds – Sowing in Drills
Make shallow drills 1-1.5cm (¼-1/2in) deep. Sow thinly to avoid too much thinning later. Space drills for upright species half the height of the plant apart. Space drills for dwarf or bushy types the full height of the plant apart.
Cover seeds by running the tip of the hoe along the ridge of the drill. Or, lightly draw a rake along the length of the drill. Then tamp down with the flat side of the hoe or rake, or firm the drill lightly with your feet.
When sowing in spring and in well-prepared soil, watering is generally unnecessary at first. In dry weather, in exposed sites or where the soil is light and dusty, moisten the soil a day or so before sowing, then again two or three days after sowing. Repeat a week later if still dry.
How to Plant Seeds – Thinning
In general, thin spring-sown seedlings once to 10-15cm (4-6in) apart; autumn-sown seedlings twice — 5-7.5cm (2-3in) apart in autumn, then 15-23cm (6-9in) apart in spring. Aim to keep the strongest seedlings. With mixed colour varieties, however, keep a selection of all sizes — small ones may bear unusual colours and will catch up in size later.