What is direct sowing and why is it worth trying?
While seeds of some popular plants are best started under glass or on a window sill – in pots or trays of compost – certain seeds can be sown directly outdoors into garden soil, in positions where they are to happily grow.
This method is often easier, and in some cases better suited to the plant, particularly those that hate root disturbance. In addition, for quick growers such as many annuals and most vegetables that comfortably complete their life cycle outside, direct sowing is best.
Direct sowing can also produce displays with a more natural look, especially if a large area is to be planted.
Many plants are best direct sown, including favourites such as Nigella, many kinds of poppy, Calendula, Nasturtium, cornflowers (Centaurea cyanus), beetroot, radish, lettuce and carrots.
A few vegetable crops, while sown outdoors, are often best transplanted from specially prepared seedbeds to final growing positions. This method is simpler than maintaining plants in pots indoors, and means plants can be grown on a bit before earlier crops finish, their positions then filled by the new seedlings. Plants worth trying this way include cabbage, broccoli, Brussels sprouts, onion and leek.
Choosing when to direct sow
When direct sowing outdoors, keep an eye on the conditions – primarily the weather and soil. This often means watching the forecast closely and waiting for suitable weather. Direct sowing is usually carried out in spring and early autumn when the soil is moist and the weather is warmer, but not too hot or dry.
Timings will vary from site to site. Lighter soils tend to warm up and dry out quicker than heavy ones, and some plants can be sown earlier than others; hardy annuals and perennials will stand frost, but half-hardy plants will not and you must wait until the cold spell has passed.
You can speed things up a bit by using ‘protected’ sowing – sowing your seeds under a cloche or plastic sheeting. The covering should be in place several days before you sow, to let the soil warm up. It should generally be above 7°c for seeds to germinate well.
Preparing your site
Before you sow it is best to prepare the ground. Where you sow might vary with what you are planting. Some ornamentals can be direct sown into existing borders, perhaps a patch at the front or even an open area with perennial plants nearby.
Vegetables or flowers for cutting are often grown in dedicated beds, which makes preparation simpler. You may even have a bed put aside simply for annual flowers.
Some plants suitable for direct sowing, including many vegetables, like a fertile soil with plenty of organic matter such as garden compost or well-rotted manure incorporated. This is usually added and allowed to settle before you come to prepare the soil for seed sowing.
Lightly fork over the soil, removing any debris, weeds, roots or large stones. The soil should be crumbly and workable and form a fairly fine tilth, at least on the very top layer; if your soil is still too wet it will be sticky or form large clods. If the ground is dust dry, you will need to water before sowing, or better still, wait for rain. Firm the ground a little by treading lightly over the area and then use a rake to level the soil and provide a surface tilth.
How to go about direct sowing
How you direct sow depends on the sort of seeds you have and your style of gardening.
For vegetables and cut flowers it is traditional, and easiest, to sow in drills: shallow depressions made by drawing a cane across a seed bed. One of the big benefits of sowing your seed in a drill is that it lets you quickly see when your seeds (not weed seeds) are starting to germinate. Your drills don’t have to be straight and can be whatever length you choose.
Germination is best if soil is moist, so use a watering can without a rose, and water lightly along the drill before you sow. Read the instructions on the seed packet and sow at the suggested depth and density.
The simplest way to sow is to pour seeds into the palm of your flat hand. Raise your fingers slightly, and a natural crease will form, along which seeds will collect and from which you can drop the seeds into the drill. Then gently fill in the drill with soil, pop in a label with the name of the seed and date sown at one end, and using a rose on your watering can, gently water the area.
When direct sowing ornamentals (rather than vegetables) a more natural effect is often welcome. This can be achieved by patch sowing: simply scattering the seed lightly and as evenly as possible over a moist prepared patch of soil – perhaps in a border – and then lightly cover with soil. Tiny seeds may not need covering, just watering afterwards. This approach can be scaled-up if sowing a bed of wildflowers, for example, where seed can be broadcast across the soil surface and watered in.
If you are wanting to sow in a gravel garden, the seeds of many plants such as Myosotis or Nigella can just be scattered directly into gravel and watered.
What to do after sowing
Some precautions need to be taken after seed has been sown. Freshly tilled earth is attractive to animals such as cats as well as birds, and these need to be stopped from disturbing the seed. You can use netting to cover the area, but it is often better and safer to simply lay cut branches around the site. Prickly holly twigs will usually put off cats.
As seedlings emerge, they are most vulnerable to slug and snail attack, so take precautions. Losing a few does not usually matter – the problem is usually worst when patch sowing in borders with nearby vegetation where these creatures can hide during the day. If unseasonal weather threatens, you may have to step in: cloches or fleece will help to protect seedlings from frost; you can also use fleece to shade plants from very warm weather. Keep the seedlings moist.
For seeds sown in drills, thinning the seedlings is often needed. This simply involves removing a proportion of the seedlings to allow enough space for those plants you’ve kept to develop properly. The space needed varies from plant to plant and is usually detailed on the seed packet. You can try transplanting thinned-out seedlings with decent roots, if you wish.
Frequently Asked Questions
Can I direct sow outside into containers? Yes, this can work brilliantly. Treat as a type of patch sowing if you want containers filled with annuals, or if you’re trying mini veg in containers. The bonus is that pots with newly emerged seedlings are easily protected, if required. Window boxes work especially well and are perfect for a row of beetroot, lettuce or radish.
How late can I direct sow? It is possible to continue direct sowing in summer. In early summer tender crops such as runner beans and pumpkins will do well, but make sure you keep on top of their watering needs. Autumn is a good time to direct sow plants such as many hardy annuals and some veg: with our milder autumn weather, the results can be good. Winter is generally too wet and cold.
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