Seed: sowing outdoors

Sowing seeds outdoors is an easy, inexpensive and fun way to grow new plants. It’s ideal for a wide range of hardy flowers and vegetables.

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Sowing hardy annual seed

Quick facts

Suitable for: Many plants
Timing: Spring until autumn
Difficulty: Easy to moderate

When to sow seeds

  • Hardy plants (annuals, biennials and perennials) – mainly spring and early autumn, plus summer for biennials such as foxgloves and honesty
  • Half-hardy annuals – late spring, after the last frost, choosing smaller, fast-growing cultivars of, for example, cosmos, nasturtiums and French marigolds
  • Vegetable seeds – mainly spring and/or summer, plus early autumn for certain hardy or fast-maturing crops

Always check seed packets for the exact planting months for each specific plant.
Bear in mind too that in milder regions sowing can begin earlier, while in colder regions it may need to be later. Also, lighter soils warm up more quickly in spring, ready for sowing, while sowing may need to be delayed in heavy, damp soils, which stay colder for longer.

How to prepare your soil

Choose a sowing site that’s suitable for the plants you want to grow – check the seed packet for details. Most flowers and vegetables need a warm, sheltered spot with plenty of sun, although some will grow in shadier sites.
To prepare for sowing:

  1. Weed the area, either by hand or with a hoe – see our guide to weeding
  2. Fork over the soil to loosen it, firm it gently, then rake level, removing any lumps of soil and large stones
Hoeing an area of lawn

You can then sow either in drills or by scattering the seeds over your prepared soil.

Top tip

Sowing in a drill makes it easy to tell which are your seedlings and which are the weeds, so you know what to remove and what to keep.

How to sow in drills

Guide to sowing seeds outdoors
  1. Make a shallow drill using a stick or trowel – check the seed packet for the correct depth. Straight drills are ideal for sowing vegetables, but with flowers you may want a less regimented result, with curving or wavy drills, or drills in random directions within your sowing area
  2. Water along the drill to dampen the base
  3. Read the seed packet to find the recommended spacing between seeds. This will vary depending on the ultimate size of the plants
  4. Pour a small amount of seeds into the palm of your hand
  5. If the seeds are large enough to pick up individually, simply place them along the base of your drill at the given spacing. If they are small, take a pinch of seeds between your thumb and finger and drop them as thinly as you can along drill
  6. Fill in the drill with the soil you removed, then firm down gently
  7. Write out a plant label so you know what you’ve sown and when, and insert at the start of your drill
  8. Water along the row using a watering can with a rose (sprinkler head) to avoid dislodging the soil 
  9. If sowing more than one row, check the seed packet for the recommended spacing between rows
Top tip

Generally, the smaller the seeds, the shallower you should sow them. Some of the smallest can simply be scattered on the soil surface. If you sow small seeds too deeply, they won’t germinate, so always check seed packets for sowing depths.

Marking out a shallow seed drill

How to sow without drills

If you want your plants to look more natural, perhaps for a wildflower patch, you may not want to sow in drills. Scattering, or broadcasting, seeds is very straightforward:
  1. Mark out your sowing area with a line of sand or insert short sticks at the corners
  2. Prepare the soil by weeding and levelling, as above
  3. Scatter the seeds thinly and evenly over the area 
    Top tip

    To get an even coverage when sowing very fine seeds, you can mix them with some sand. This lets you scatter them more thinly and you can see where you’ve sown.

  4. Firm the seeds into the soil with the back of your rake or trowel
  5. Small seeds generally don’t need covering, while larger seeds can be covered with a light scatterin of soil or compost
  6. Water using a watering can fitted with a rose
  7. Add a label, so you remember what you’ve sown and where
With this method, weeding has to be done by hand, so it’s useful if you can recognise which seedlings are weeds - see our guide to common weeds.

How to sow seeds in containers outdoors

You can also sow seeds into containers, either as their final growing position, or temporarily until large enough to plant into the ground.
Seeds to sow in containers outdoors include:
  • Vegetables - such as small, fast-growing salads, short-rooted carrots, radishes, dwarf beans, chard and more 

    Vegetables in containers

    Vegetables in containers

    Grow your own colourful Chard

    Grow your own colourful Chard
  • Fast-growing annual flowers - as part of a container display, such as nasturtiums and pot marigolds, or a wildflower mix
  • Herbs - such as parsley and coriander
  • Hardy trees and shrubs - such as acorns, conkers, holly berries, usually in autumn 

    Trees and shrubs from seed

    Trees and shrubs from seed

    Plant an acorn grow a mighty oak

    Plant an acorn grow a mighty oak

Sowing in containers outdoors is easy: 
  1. Fill a seed tray, modules or pots with seed compost or sieved multipurpose compost, and firm down gently to just below the rim 
    Top tip

    Seed compost is preferable for smaller seeds, as it has a finer texture than multipurpose. It also containers fewer nutrients, which suits young seedlings.

  2. Larger seeds can be pressed into the compost individually, at the spacing recommended on the packet, while smaller seeds should be scattered as thinly as possible on the surface
  3. Most seeds should then be covered with a fine layer of compost, vermiculite or perlite. Check seed packets to see how deeply to cover the seeds you are sowing
  4. Water gently using a watering can fitted with a rose (sprinkler head), to avoid dislodging the seeds
  5. Label the container, so you remember what you’ve sown and when
  6. Place in a warm, sheltered, sunny spot, and water regularly to prevent drying out
It's worth noting that whilst most seeds can be sown direct from the packet, a few with tough seed coats may need pre-soaking, scraping or nicking (with sandpaper or a knife) to aid germination – seed packets will provide details. A few others need a period of cold or heat before they will germinate – see our guide to sowing tree seeds for details.

Growing winter salads in containers

Growing winter salads in containers

How to look after your seedlings

For best results, seedlings need regular attention, as they can be very vulnerable in the first few months, until sturdy and well rooted. In particular, ensure they don’t go short of water or get outcompeted by weeds, and are protected from pests and hard frosts. Seedlings will usually appear within a couple of weeks – check the seed packet for exact timings
  • Keep slugs and snails at bay - Slugs and snails like to eat soft, juicy seedlings, so keep populations at bay and/or put protection in place – see our guides to controlling slugs and snails
  • Keep the compost slightly moist at all times – seedlings will soon die if they get too dry as they don’t have deep roots. Check the soil regularly and water if it feels dry below the surface. Use a watering can with a fine rose, so you don’t damage the seedlings
  • Weed every few weeks - so the seedlings don’t have competition for water, light and nutrients. Pull weeds out by hand or hoe between rows on dry days – see our guide to weeding
  • Protect from frost - hardy seedlings from autumn sowings should cope with light frosts, but keep horticultural fleece or cloches handy and cover them if a hard frost is forecast
  • Make sure they have space - most seedlings need thinning out after a month or so. Overcrowding can hinder growth and make them more susceptible to disease. Check the seed packet for the recommended final spacing
  • Thin out if need be - first remove the weakest, smallest seedlings. Then, if you still haven’t reached the correct final spacing, remove a few more where necessary, leaving strong, healthy, well-spaced seedlings. Pull out the unwanted seedlings carefully, so the roots of the remaining plants aren’t loosened. Firm the soil down afterwards and water gently to settle it back in place
Top tip

With flowering plants, it’s usually beneficial to pinch out the tips of long shoots to encourage branching. This will result in bushier plants that will carry more flowers.

RHS guide to recognising common weeds

RHS guide to recognising common weeds

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