Summer annuals

Published on November 21st 2020
A close up of a purple flower
Summer annuals can transform almost any patch of soil or dull corner into a vibrant, colourful display. By simply sowing seeds of annuals at the start of the season, you can grow a beautiful summer garden without much effort. Whether you start in seedling trays or directly into beds, containers or hanging baskets, you have to give summer annuals a go this season!
A vase of flowers on a table
Most annual plants can be sown directly into the ground from early spring onwards for spring and summer flowering.

Summer annuals planting tips

  • For the most effective display, position plants in groups., and group according to colour and height.
  • When sowing or planting summer annuals it is important to group plants with similar light and water requirements together.
  • Plant the tallest varieties at the back, medium-height in the middle and the lowest at the front.
  • When growing annuals in containers consider planting low-growing or those with a trailing habit like cascade petunias for sunny spots or petunias for shady positions.
  • To brighten up perennial borders, plant annuals in the spaces between the permanent plants.
A close up of a flower

Preparation is key

  • Before sowing, start preparing the beds by removing old plants left from the previous season.
  • Dig over garden beds, add a generous dressing of compost, and scatter a light dressing of bone meal (high in phosphorous to help flower formation).
  • Just before sowing seeds or planting seedlings, rake the soil to obtain a crumbly, easily worked surface.
  • If you’re planting in containers or hanging baskets, use potting soil that drains well and retains moisture.
  • Water seedlings well before planting out.
A pink flower on a plant

Time to plant!

Direct sowing
  • Seeds can either be scattered over the whole area or sown in grooves.
  • When considering the distance between the grooves, keep in mind the size and height of the plants at maturity. Usually, this information can be found on the seed packet.
  • After sowing seeds in grooves or scattering across the bed, lightly cover them with soil by raking along the length of the grooves.
  • Firm down the soil with the flat side of a rake, ensure most seeds are covered and protected from the sun.
Tip | Sow seeds thinly to make thinning easier.
A person standing in a garden
Transplanting seedlings
  • Plant out seedlings on a cool overcast day, or early in the morning or later in the afternoon when the sun is less harsh.
  • When removing seedlings from their trays, do not pull the leaves or stems, rather push out the root ball from the bottom of the seedling tray.
  • Plant seedlings out at the same depth as they were growing in the seedling tray.
  • Gently firm down the soil to remove air pockets and water thoroughly.
  • Check on your plants regularly to ensure the newly planted seedlings do not dry out.
Tip | Rather than sprinkling lightly, water the seedlings deeply to encourage deep root growth.
A box of pizza

Caring for annuals

  • Fertilise seedlings with a good general fertiliser for flowering plants. For garden beds, use a granular fertiliser and for containers or hanging baskets, use a liquid fertiliser.
  • Remember to deadhead flowers to keep your plants neat and tidy and also to encourage flower production.
A close up of a bunch of pink flowers

Summer annuals

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