Vegetables to Plant
Direct sow outdoors:
- Carrots: Continue sowing thinly in light, sandy soil for best results. Protect young seedlings from carrot root fly with fleece.
- Beetroot: Sow in rows 30cm apart. Pick baby beets early or leave for full size.
- Lettuce: Sow little and often (every 2 weeks) to avoid a glut. Prefers partial shade during hot days.
- Radishes: Still ideal this month. Quick to mature; great for filling gaps between slower crops.
- Spring Onions: Sow thinly, about 1cm deep. Best for summer salads.
- Turnips: Sow small batches for tender young roots ready by summer.
- Chard: Sow now for harvests throughout the summer and into autumn.
Transplant seedlings outdoors:
- Tomatoes: Harden off and plant outside after all risk of frost has passed, usually mid- to late May. Stake and tie as they grow.
- Courgettes (Zucchini): Plant out after last frost; give plenty of space (about 90cm between plants).
- Runner Beans: Sow direct or transplant young plants outdoors. Provide tall supports immediately.
- French Beans: Like warmth; sow now in fertile, well-drained soil.
- Cucumbers: Outdoor varieties can go out later in May. Indoor cucumbers can be planted in greenhouses now.
Start indoors or undercover:
- Sweetcorn: Start in deep pots now; transplant when plants are about 15cm tall and soil is warm.
- Pumpkins & Squashes: Sow indoors now for planting outside in June.
Herbs to Plant
Direct sow or transplant outdoors:
- Coriander: Prefers cooler, moist conditions. Sow in partial shade for better leaf production.
- Chervil: Cool-weather herb; best sown in shady spots.
- Basil: Sow under cover early May, then plant outdoors toward the end of the month.
- Dill: Sow directly into well-drained soil. Pinch flowers early if you want more leaves.
Perennials to establish outdoors:
- Oregano: Hardy herb — transplant seedlings or young plants outdoors this month.
- Sage: Likes sunny, well-drained sites. Plant out now.
- Thyme: Very low-maintenance once established. Ideal for dry, sunny corners.
Flowers to Plant
Hardy annuals direct sow:
- Sunflowers: Sow seeds directly into ground now for towering blooms by late summer.
- Nasturtiums: Easy to grow; prefer poorer soils. Both flowers and leaves are edible.
- Cosmos: Sow direct now for lovely mid- to late-summer color.
Tender annuals transplant outdoors:
- Marigolds: Sow indoors early May, plant out after frost risk. Attracts beneficial insects.
- Zinnias: Plant out seedlings mid- to late May; loves warm, sunny sites.
- Petunias: Great for containers and bedding schemes. Plant out after mid-May.
Biennials to sow for next year:
- Foxgloves: Sow in seed trays or directly in a nursery bed. They will flower next spring.
- Wallflowers: Start from seed now for a spring display next year.
Key May Gardening Tips
- Harden off tender plants: Gradually introduce indoor-raised plants to outside conditions before planting out fully.
- Watch out for late frosts: Particularly early in May; cover tender crops overnight with cloches or fleece if needed.
- Mulch garden beds: Retains moisture and suppresses weeds as the weather warms up.
- Water newly sown seeds: Water little but often to ensure consistent germination.
- Stagger sowings: Sow little and often for a continuous harvest, especially for salad crops.
Bonus: 3 Things to Hold Off Planting Until Late May or June
- Melons: Need really warm, protected conditions.
- Aubergines (Eggplant): Only transplant outdoors when temperatures are consistently above 10°C at night.
- Chillies: Best kept in a greenhouse or polytunnel unless your area is very sheltered and sunny.
