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What to Sow and Grow in May: A Complete Guide

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May is a fantastic month for gardeners, with warmer soil and longer days providing perfect conditions to sow seeds and plant young plants. Below, we’ve put together a detailed guide on what you can sow and grow right now. Seeds are available from molesseeds.co.uk and young plants can be purchased from gardenerskitchen.co.uk.

Each entry includes handy gardening tips and notes on pests and diseases to watch out for.

Vegetables to Sow from Seed in May:

  • Carrots
     Tip: Sow thinly in well-drained soil. Thin seedlings early to avoid overcrowding.
    Pests: Watch for carrot fly — use fine mesh or fleece.
  • Chilies
     Tip: Sow indoors in warmth. They love heat and light!
    Pests: Aphids can be a problem; check leaves regularly.
  • Courgettes
     Tip: Sow directly outdoors after the last frost or start inside for earlier crops.
    Diseases: Powdery mildew is common in dry weather — water at the base, not the leaves.
  • Cucumbers
     Tip: Grow in a greenhouse or sheltered spot. Feed regularly once fruiting starts.
    Pests: Keep an eye out for red spider mites.
  • Fennel
     Tip: Sow directly and thin carefully. Prefers cool, moist conditions.
    Pests: Slugs and snails can damage young plants.
  • Garlic
     Tip: You can still sow cloves in May for an autumn harvest in some areas.
    Diseases: Watch for rust on leaves.
  • Leeks
     Tip: Sow thinly and transplant when pencil-thick.
    Pests: Leek moth larvae can cause problems — use fleece.
  • Melons
     Tip: Sow under cover. They thrive in warmth and humidity.
    Diseases: Powdery mildew can affect growth — ensure good ventilation.
  • Onions
     Tip: Sow from seed or sets. Keep weeds down to prevent competition.
    Pests: Onion fly and downy mildew can be issues.
  • Pak Choi
     Tip: Best sown in cooler weather to prevent bolting.
    Pests: Flea beetles love Pak Choi — protect seedlings with fleece.
  • Parsnips
     Tip: Sow fresh seed directly where they are to grow. Germination can be slow.
    Diseases: Canker can affect roots; rotate crops annually.
  • Peas
     Tip: Sow successively for continuous harvests. Support with pea sticks or netting.
    Pests: Birds love young shoots — net them early.
  • Peppers
     Tip: Sow under cover; they thrive with lots of sun and warmth.
    Pests: Aphids and spider mites can appear — inspect often.
  • Potatoes
     Tip: May is good for second early and main crop varieties.
    Diseases: Blight is a risk in wet weather — choose resistant varieties if possible.
  • Spring Onions
     Tip: Sow thinly every few weeks for a continuous crop.
    Pests: Slugs and onion fly can attack young seedlings.
  • Aubergines
     Tip: Sow under cover in warmth. Stake plants as they grow.
    Pests: Aphids and red spider mites are common in greenhouses.
  • Capsicum Peppers
     Tip: Like chilies, they prefer warm conditions and regular feeding.
    Pests: Look out for aphid infestations.
  • Gherkins
     Tip: Sow indoors and plant out after frost; train up supports.
    Pests: Watch for cucumber beetles and mildew.
  • Sweet Potatoes
     Tip: Plant slips (young plants) in ridges in a sunny, sheltered spot.
    Pests: Keep an eye out for wireworms in the soil.
  • Tomatoes
     Tip: Sow indoors; harden off before planting outside.
    Diseases: Blight is a risk — water the soil, not the leaves.
  • Broccoli
     Tip: Sow for an autumn harvest. Protect seedlings from pests.
    Pests: Cabbage white butterfly larvae can devastate crops.
  • Chard
     Tip: Sow little and often for a continuous supply.
    Pests: Leaf miners can burrow into the leaves.

Vegetables to Grow from Young Plants in May:

  • Beetroot
     Tip: Transplant carefully to avoid disturbing roots.
  • Broad Beans
     Tip: Support plants and pinch out tops to deter blackfly.
  • Brussels Sprouts
     Tip: Firm in well to avoid wind rock; they need a long growing season.
  • Cabbage
     Tip: Plant deeply and firm in well. Net against pigeons.
  • Celery
     Tip: Keep soil moist for crisp stems; water regularly.
  • Celeriac
     Tip: Needs consistent watering and regular feeding.
  • Kale
     Tip: Very hardy. Harvest young leaves for a tender crop.
  • Lettuce
     Tip: Plant in part-shade to avoid bolting in hot weather.
  • Spinach
     Tip: Needs plenty of water; sow bolt-resistant varieties if hot weather is expected.
  • Sweetcorn
     Tip: Plant in blocks for good pollination.
  • Horseradish
     Tip: Plant in a pot to contain its vigorous roots.
  • Asparagus
     Tip: Plant crowns now for future harvests; it takes patience but is worth it!

Herbs to Grow from Seed in May:

  • Basil
     Tip: Loves warmth; perfect for windowsills or greenhouses.
  • Angelica
     Tip: A large plant — allow plenty of space.
  • Borage
     Tip: Self-seeds easily; great for bees.
  • Chives
     Tip: Grow in clumps and divide every few years.
  • Coriander
     Tip: Best sown direct; bolt-resistant varieties available.
  • Dill
     Tip: Needs shelter from strong winds; dislikes being transplanted.
  • Echinacea
     Tip: Needs good drainage and full sun.
  • Garlic Chives
     Tip: Similar care to ordinary chives; very ornamental.
  • Lavender
     Tip: Sow in sandy, free-draining soil.
  • Marjoram
     Tip: Perfect for pots and containers; loves sun.
  • Mint (Moroccan)
     Tip: Grow in pots to contain its spread.
  • Oregano
     Tip: Needs full sun and well-drained soil.
  • Parsley
     Tip: Takes time to germinate; soak seeds overnight before sowing.
  • Rosemary
     Tip: Loves a sunny, sheltered position with well-draining soil.
  • Sage
     Tip: Prune after flowering to keep plants bushy.

Seeds for Continuous Crops from May Onwards:

To keep your garden productive through the summer, continue sowing the following every few weeks:

  • Lettuce
  • Spinach
  • Spring Onions
  • Peas
  • Chard

Sowing little and often ensures a constant supply of fresh produce!

Whether you’re sowing from seed or planting young plants, May offers endless opportunities to grow something delicious. For seeds, head over to molesseeds.co.uk, and for strong, healthy young plants, visit gardenerskitchen.co.uk.

Happy gardening!