What to sow and grow in May

Poppy 'Cherry Glow' by Thompson & Morgan — available now

Sow poppies to attract pollinators
Image: Poppy 'Cherry Glow' from Thompson & Morgan

May is here at last. The weather is warmer and sunnier, the days are getting longer and summer is definitely on its way.

For more information about other gardening jobs to start in May, read our helpful companion guide today, or check out our top picks to keep you busy sowing and growing this month:

Flowers to sow and grow in May

Larkspur ‘The Seven Dwarves' by Thompson & Morgan — available now

If want a dazzling display this year, start larkspur off in pots.
Image: Larkspur 'The Seven Dwarves' from Thompson & Morgan

In the greenhouse / indoors

  • Start larkspur (Consolida ajacis) off in potstry larkspur ‘T&M Improved’. This annual has similar flowers to delphinium, but is much easier to grow.
  • Sow helipterum indoors — they make excellent dried flowers.
  • Start salvia off indoors this month or buy garden ready plants to brighten up your summer bedding. Try Salvia patens 'Blue Angel' for fashionable cobalt flowers.
  • Start to sow biennials like foxgloves, dianthus plants and wallflowers in seed trays, for flowering next year.
  • Sow perennials, like delphiniums, lupins, aquilegia and primula, in seed trays for flowering next year and in the years to come. Take inspiration from our perennials hub for more sowing & growing advice.
  • Plant up pots and baskets of summer bedding plants and harden off before placing in position. In cold areas wait until June to do this. Try begonia x tuberhybrida 'Apricot Shades Improved' F1 Hybrid in containers for gorgeous peach flowers. For more information, read our 'Perennial Plants for Pots' article.
  • Plant up certain varieties of climbing perennials, like Passion Flowers, in a sheltered, warm spot - such as a conservatory or greenhouse, or at the foot of a south-facing wall.

Direct sow outdoors

Plant outdoors

Herbs & vegetables to sow and grow in May

woman hand sowing cucumber seeds in module trays

Start cucumbers off in module trays this May
Image: Tortoon

In the greenhouse / indoors

  • Start off sweetcorn in modules ready for planting out once all risk of frost has passed - Try supersweet sweetcorn ‘Summer Glow’ and grow at least 12 plants for good pollination and cropping.
  • Sow basil in pots for the greenhouse or patio - this Mediterranean staple thrives in warm conditions.
  • Sow pumpkin, squash and courgette seeds undercover now.
  • Try sowing lettuce in module trays under glass for transplanting into the garden later. Sow every 3 or 4 weeks for continuous harvesting — try lettuce ’All The Year Round’ for reliable cropping.
  • Sow cucumber and gherkin seeds in individual pots or modules.
  • Sow runner beans and french beans undercover, sowing individually into module trays for planting out after the risk of frost has passed.
  • Start brassica and leafy green seeds under cover now — yes, it really is time to think ahead to winter cropping!
  • Sow perennial herb seeds, such as rosemary, sage, thyme ‘Old English’, lovage and lemon balm under cover.
  • Plant glasshouse tomato plants in beds or growing bags. For more information about growing your own tomatoes, check out our tomatoes hub page.

Direct sow outdoors

  • Direct sow borage and use the flowers for garnishing salads and desserts.
  • Try sowing comfrey seeds in a neglected corner of the garden — it can be used to make fertiliser or for mulching, and is a rich source of nutrients. Direct sow or sow into seed trays indoors.
  • Sow beetroot and chard seeds thinly, directly into the ground.
  • Sow broccoli and calabrese in a nursery bed for transplanting later on, or sow directly in your vegetable plot.
  • Direct sow brassica and leafy green seeds like cabbage and Brussels sprouts. Net them early on to prevent cabbage-white butterflies laying their eggs on the leaves.
  • Direct sow carrot seeds in rows and protect with horticultural fleece or enviromesh to prevent carrot-fly attack.
  • Sow red chicory radicchio 'Rossa di Treviso precoce' directly into the soil for colourful flavoursome salad leaves.
  • Sow chive, coriander, dill and parsley ‘Laura’ seeds directly into the ground or in containers.
  • Try growing hardy Lamb's Lettuce ‘Favor’ outdoors, for summer and winter salad leaves with ‘nutty’ flavour.
  • Direct sow kohl rabi 'Kolibri' F1 Hybrid — it will be ready in as little as 8 weeks.
  • Sow peas directly into the ground, or start them off in modules if mice are a problem.
  • Try direct sowing nutritious pak choi ‘Tricolour Mix, sow seeds every 3 weeks for a continuous crop.
  • Direct sow your parsnip seeds now. Sow 3 or 4 seeds every 20 cm and thin to the strongest plant.
  • Sow radish seeds directly into the soil for a quick and easy home-grown salad - try Chinese radish 'Mooli Kumbong' F1 in containers for flavoursome white roots.
  • Sow salad leaves directly into the ground or in containers.
  • Start cauliflower ‘All The Year Round’ seeds under cover.
  • Sow perpetual spinach seeds in soil enriched with plenty of organic matter for prolific cropping and resistance to bolting in dry soils.
  • Sow spring onion seeds in drills outdoors for a quick crop to flavour salads and stir fries.
  • Try Swiss chard sown outdoors for a colourful crop — it even looks great in flower beds!
  • Sow swede seeds outdoors in a rich, fertile soil for autumn and winter crops - Try British bred swede ‘Tweed’.
  • Start to sow turnips now for a great addition to casseroles and stews - Try turnip ‘Golden Ball for attractive golden flesh.
  • Grow your own watercress in containers, making sure the container is sitting in 2-3 inches of water at all times.

Plant outdoors

image of young leeks getting planted in their final positions

It's time to plant leeks out to their final position.
Image: Shutterstock

  • Plant out brassicas and leeks to their final positions.

Fruit to sow and grow in May

Melon 'Outdoor Wonder' F1 Hybrid from T&M

Sow Melon seeds now for juicy summer harvests.
Image: Melon 'Outdoor Wonder' F1 Hybrid from Thompson & Morgan

In the greenhouse / indoors

  • Sow melons in individual modules now — for the best crops, try growing a variety suited to the British climate, such as 'Outdoor Wonder' F1 Hybrid. For more information about growing your own fruit, check out our fruit hub.

Keep one step ahead — what to order in May

Tomato ‘Sungold’ from T&M

Order tomato plug plants now to pot on and harden off after the last frosts.
Image: Tomato 'Sungold' from Thompson & Morgan

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