Which Vegetables and herbs to Sow and Grow in May: A Complete Guide
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
- Tips: Sow directly into well-prepared, stone-free soil. Thin seedlings carefully to prevent overcrowding.
- Pests and Diseases: Watch for carrot fly. Protect young carrots with fine mesh or fleece.
Chilies
- Tips: Start seeds in a greenhouse or indoors. Provide plenty of light and warmth.
- Pests and Diseases: Be vigilant for aphids and spider mites, particularly under glass.
Garlic
- Tips: Although traditionally planted in autumn, spring garlic can be sown in May for a later harvest. Choose softneck varieties.
- Pests and Diseases: Avoid waterlogged soil to prevent rot. Watch for rust and downy mildew.
Leeks
- Tips: Sow in a seedbed or pots, then transplant when pencil-thick. Firm well and water in.
- Pests and Diseases: Leek moth and allium leaf miner can cause damage; use insect-proof mesh if necessary.
Melons
- Tips: Start seeds indoors in a warm, sunny place. Transplant under cover or into very warm outdoor spots.
- Pests and Diseases: Keep an eye out for powdery mildew and aphids.
Vegetables to Grow from Young Plants in May
Beetroot
- Tips: Transplant young plants carefully to avoid root disturbance.
- Pests and Diseases: Flea beetles and downy mildew can be issues. Use protective fleece early on.
Cabbage
- Tips: Plant out cabbages, spacing them well. Net to protect against pigeons.
- Pests and Diseases: Cabbage white butterfly caterpillars can devastate crops — netting helps a lot.
Celery
- Tips: Choose a trench or self-blanching variety. Water regularly and feed with a high-nitrogen fertilizer.
- Pests and Diseases: Slugs love young celery — keep the area clear of debris.
Spinach
- Tips: Plant spinach seedlings into fertile, moist soil. Harvest leaves regularly to encourage new growth.
- Pests and Diseases: Watch for leaf miners and mildew, particularly in warm, humid weather.
Asparagus
- Tips: Plant young asparagus crowns in deeply prepared beds. Remember, patience is key — don’t harvest until the second year.
- Pests and Diseases: Asparagus beetles can cause damage; remove them by hand.
Herbs to Grow from Seed in May
Coriander
- Tips: Sow in succession for a continual harvest. Prefers cooler, partially shaded spots.
- Pests and Diseases: Aphids and powdery mildew can be an issue.
Garlic Chives
- Tips: Sow thinly and thin out seedlings to prevent overcrowding.
- Pests and Diseases: Generally trouble-free but can suffer from rust in damp conditions.
Lavender
- Tips: Sow into trays of compost and transplant seedlings once large enough. Loves full sun and well-drained soil.
- Pests and Diseases: Root rot in poorly drained soils is a risk.
Lemon Balm
- Tips: Sow thinly into modules and plant out after risk of frost has passed.
- Pests and Diseases: Can attract aphids but is generally resilient.
Lemon Verbena
- Tips: Start indoors and move outside after frosts. Prefers sheltered, sunny positions.
- Pests and Diseases: Check for spider mites.
Continuous Cropping Seeds from May Onwards
Carrots, Spinach
- Tips: Sow little and often (every 2-3 weeks) to ensure a steady supply through summer and into autumn.
- Pests and Diseases: Stay vigilant with pest control measures and crop rotation to minimize disease build-up.
General Gardening Tips for May
- Water newly sown seeds and young plants regularly, especially in dry spells.
- Protect tender plants from late frosts with fleece.
- Keep weeding! Young seedlings can easily be overwhelmed.
- Harden off indoor-grown plants before transplanting outside.
Pest and Disease Watch
- Slugs and snails are especially active now — use organic slug pellets or beer traps.
- Aphids multiply quickly in warm weather; use biological controls or soap sprays.
- Caterpillars and beetles can munch young leaves — hand-pick where possible or use mesh covers.
May is a month full of promise in the garden — with a little care, you’ll have a productive season ahead!