Organic Gardening - what to sow in May

May's warmer temperatures make it a great time to start planting out your seedlings, after hardening them off. If you prefer to direct sow your seeds, now's the time to get busy.

Flowering Plants

Flowering Plants

  • Direct sow sunflower seeds, zinnias and cosmos.
  • Plant summer bedding plants like petunias and marigolds.
  • Start dahlias in the ground or large pots.
  • Plant gladioli bulbs in patio pots and flower beds for summer blooms.
  • Transplant foxgloves for a striking summer border.
  • Deadhead spring bulbs to prevent seedheads forming.
  • Pinch out sweet pea tips to encourage bushy growth.
  • Water plants regularly to prevent drying.

Vegetables

Vegetables

  • Sow carrots, beetroot, and parsnips directly outdoors.
  • Harden-off tomato plants and transplant to the garden.
  • Transplant cabbage and cauliflower seedlings.
  • Transplant courgette plants and squash seedlings.
  • Sow runner beans, French beans, and pea seeds.
  • Start sweetcorn in pots under cover.
  • Thin out seedlings to avoid overcrowding.
  • Water vegetable beds deeply during dry spells.

Fruit

Fruit

  • Net strawberries to protect them from birds.
  • Mulch around raspberries and blackberries.
  • Harvest mature rhubarb stems (over 3 years old).
  • Water young fruit trees and bushes regularly.
  • Check for aphids on tender shoots and remove by hand.
  • Give soft fruit bushes a high potassium feed to prompt stronger fruiting.
  • Thin out gooseberry stems using sharp secateurs to promote air circulation.
  • Apply a thick mulch layer around fruit plants.

General Garden Jobs

General Garden Jobs

  • Fertilise garden beds with organic compost.
  • Mow lawns but leave some areas for wildflowers.
  • Ventilate greenhouses to avoid overheating.
  • Water plants deeply during dry periods.
  • Remove weeds regularly to prevent them from seeding.
  • Add supports for taller plants as they grow.
  • Divide crowded summer flowering perennials and replant.
  • Encourage natural predators for pests by growing a mix of native blooms.

Pots & Containers

  • Sow salad mixes or lettuce and rocket seeds in window boxes for easy harvests.
  • Refresh soil and feed perennials in containers.
  • Move pots into sunny spots to encourage growth.

Wildlife

  • Install an insect hotel to support bees and pollinators.
  • Provide water dishes for thirsty wildlife.
  • Leave some areas of grass uncut to encourage greater biodiversity.

Pruning

    • Prune early-flowering shrubs like forsythia after their blooms fade.
    • Trim back dead wood from roses and other shrubs to stimulate growth.
    • Prune out frost-damaged branches on fruit trees.

Organic Gardening Tip: Mulching helps to retain soil moisture, suppress weeds, and keeps soil temperatures stable - perfect for setting up a strong, resilient garden.

Sophie Essex

Written by: Sophie Essex, garden writer

Sophie Essex is a freelance garden writer with a passion for horticulture and environmental conservation. She's qualified with a BSc in Botany/Plant Biology from the University of Plymouth and a MSc in Biodiversity and Taxonomy of Plants from The University of Edinburgh.

Sophie has also worked as a professional gardener and landscaper, developing her practical skills at Cornwall's Eden Project, the National Trust for Scotland, and the Royal Botanic Garden Edinburgh.