Growing plants from seed is a thrilling process if, of course, conditions and care is right for the species being propagated. Unfortunately, judging by letters received, quite a few of you are having problems with seed-sowing techniques. It is hoped that the following information will help.
Generally speaking — and excluding seeds requiring specialist treatment — seeds for annual flowers, vegetables and herbs are, in our climate, sown either in early autumn or early spring when soil conditions are warm — not summer hot or winter cold. Some species can be both spring and autumn sown whilst others are more selective, such as hot weather-loving green chillies, okra and courgettes which are spring sown, and cool to cold weather-loving mustards, broccoli and kale, which perform best when sown in autumn for harvesting over the winter months.
With knowledge, experience and items such as polytunnels, cloches and shade-netting, it is possible to start off a surprisingly wide range of plants all year round, but we will stick to simple things to grow here.
There are two basic ways of seed sowing:
Directly in the ground
Many seeds can be sown in carefully spaced and labelled rows, in prepared seed beds from which, once seedlings are established, the young plants can be transplanted into their actual growing position. This method is ideal for vegetables such as cabbages, cauliflowers, broccoli, kale, lettuce, tomatoes, chillies, capsicums and Swiss chard/leaf beet, and flowers such as hollyhocks, rudbeckia, gaillardia, antirrhinums, sweet Williams and wallflowers.
There’s nothing more satisfying than growing your garden all the way from seed to harvest. So, get ready to flex your green thumb
Prepare seed-beds at least two weeks in advance. Do this by digging over the soil, removing all weeds, stones and other debris in the process. Add a good amount of old, well-rotted, preferably organic manure, fully rotted down household compost and, if soil is heavy clay or extremely sandy, a reasonable amount of fresh sweet earth, too. When everything is thoroughly mixed in, rake the surface, breaking up any lumps.
Working one row at a time and using string to mark out straight rows, use something like the rake handle to scratch out ‘drills’ to sow the seeds in. The depth of each ‘drill’ — sowing line — depends on which seeds are being sown. Sow the seeds, taking care to allow each seed plenty of space to grow into a strong seedling, and carefully cover them over with lightly raked soil. Once you have finished sowing, lightly water the bed to settle them in and keep the bed moist, not soaking wet, by watering/spraying each evening or as needed. Do not allow the soil to totally dry out at any stage, otherwise seed germination will be adversely affected.
Keep the seed-bed free of weeds and, once the seedlings have reached four to six true leaf (do not count the first-to-emerge pair of tiny leaves) stage, they are ready to be transplanted at distances (usually specified on seed packets) suitable for them to reach maturity.
Starting off with as many seeds as possible in seed beds circumvents the need to purchase seed trays and other stuff. However, for some more fussy species, seed trays or plug plant trays are recommended.
Some seed varieties do best when sown in prepared ground directly where they are to grow. This category includes all root vegetables (carrots, beetroot, radish, etc.), peas and beans, nasturtiums, borage and easy-to-grow annual flowers such as poppies, larkspur, candytuft, coreopsis, Queen Anne’s lace, dill, coriander and parsley.
Sowing seeds in seed trays and plug plant trays
It is worthwhile when sowing very expensive, difficult to germinate seeds or something you only have a few seeds for, to sow them in seed trays or plug plant trays, so that they can be carefully monitored. Species which appreciate this treatment include lobelia, geraniums, carnations, asparagus, artichokes, strawberries, lavender, thyme, oregano and sage.
Use top quality, homemade compost, mixed 50/50 with good garden soil that has been sieved to remove stones/lumps, or purchase a specified seed-sowing compost, if preferred.
Fill your seed trays/plug plant trays to within about half an inch of the brim, damp down the compost/soil, sow your seeds at the recommended depth, lightly sieve a covering of soil/compost over them and gently water them using a fine sprayer. Keep the compost/soil lightly moist but not overly wet, or the seeds/seedlings may rot.
Some seeds need exposure to light in order to germinate; these are surface sown.
Mix small seeds with a little aata (flour) before sowing, as this helps in spacing them out.
Larger seeds can be sown in individual containers such as recycled yogurt pots with holes made in the base for drainage.
When transplanting seedlings, do so with great care as many are brittle and easily damaged.
Be aware that more seeds, seedlings and plants are lost through overwatering than from pests and diseases. Little and often is far better than drowning plants and their roots at any stage.
*A note on seed-sowing depths:
• The smaller the seed the closer to the surface it is sown. Poppy seeds, for instance, are happy simply to be raked into the surface soil and no more.
• Slightly larger seeds, such as cosmos, lettuce, endive and radicchio are sown just beneath the soil surface.
• Medium-size seeds such as those of cabbage family, larkspur, etc. are sown approximately quarter to half-an-inch deep.
• Larger seeds, such as peas, sweet peas and nasturtiums are individually sown at a depth of about one to two inches.
• Large seeds, broad beans being a good example, appreciate a planting depth of about three to four inches.
• Always check seed packets for special information, recommended sowing depths and for planting out distances when seedlings are grown.
Please continue sending your gardening queries to firstname.lastname@example.org. Remember to include your location. The writer does not respond directly by email. Emails with attachments will not be opened.
Published in Dawn, EOS, November 17th, 2019