May is one of the most important and productive months in the UK gardening calendar. By this point, soil temperatures have risen significantly, frost risk is reducing in most regions, and gardeners can finally sow and plant a wide range of crops directly outdoors.
For allotment holders, home growers and beginners, May is when the garden shifts into full production mode. Seed trays give way to direct sowing, and outdoor beds start filling rapidly.
In this guide, we’ll cover exactly what to sow in May in the UK, including vegetables, herbs and flowers for both outdoor and protected growing.
Quick Answer: What Can You Sow in May?
May is a peak sowing month in the UK.
May is also a key month for transplanting previously sown seedlings into final growing positions.
Vegetables to Sow in May
Carrots
May is still a strong sowing month for carrots, especially for succession planting.
Key tips:
- Sow directly into soil
- Avoid heavy, stony ground
- Thin seedlings carefully
Good varieties: Nantes, Chantenay, Autumn King, Amsterdam Forcing.
Beetroot
Beetroot continues to be one of the easiest and most reliable crops to sow in May.
Benefits:
- Fast germination
- Multiple harvests
- Suitable for succession sowing
Lettuce
May sowings provide continuous summer salad harvests.
Recommended varieties: Little Gem, Lollo Rosso, Oakleaf, Romaine types.
Spinach
Spinach can still be grown in early May before summer heat causes bolting.
Spring Onions
A reliable crop for repeated sowing throughout May.
Radishes
Fast-growing and ideal for filling gaps between slower crops.
Beans to Sow in May
May is one of the most important months for beans in the UK.
French Beans
- Sow outdoors once frost risk passes
- Climbing or dwarf varieties available
Runner Beans
A classic UK crop for high yields.
- Sow indoors early May or outdoors later in the month
- Provide strong support structures
Popular varieties: Scarlet Emperor, Painted Lady.
Courgettes, Squash and Pumpkins
May is the main sowing window for these high-yield crops.
Courgettes
Extremely productive and fast-growing.
Pumpkins
Require space and a long growing season.
Squash
Includes butternut and winter squash varieties.
Key tips:
- Sow indoors or under cover early May
- Plant out after frost risk ends
- Feed regularly during growth
Sweetcorn
Sweetcorn thrives when sown in May.
Key requirements:
- Warm soil
- Good spacing for pollination
- Shelter from wind
Cucumbers
Cucumbers can be sown indoors or in greenhouses.
Types include:
- Ridge cucumbers (outdoor)
- Greenhouse cucumbers
Brassicas to Sow in May
Kale
Highly productive and long-lasting crop.
Cabbage
Late summer and autumn varieties can be sown.
Broccoli (Calabrese)
Fast-growing varieties suitable for summer harvests.
Herbs to Sow in May
Basil
May is ideal for basil once temperatures are reliably warm.
Coriander
Best sown in small batches for continuous harvest.
Dill
Great for salads, pickling and companion planting.
Parsley
Still suitable for sowing but slow to germinate.
Chives
Reliable perennial herb for containers and borders.
Flowers to Sow in May
Sunflowers
One of the easiest and most rewarding flowers to grow.
Nasturtiums
Edible flowers that also deter pests.
Marigolds (Calendula)
Great for pollinators and companion planting.
Cosmos
Long-flowering and excellent for wildlife gardens.
Zinnias
Bright, colourful and ideal for cutting flowers.
Sweet Peas
Late sowings still possible for summer blooms.
Nigella
Produces attractive flowers and decorative seed pods.
What Can Be Planted Outdoors in May?
May is a major planting month in the UK garden.
You can plant:
- Tomato plants (after hardening off)
- Courgette plants
- Squash and pumpkin plants
- Sweetcorn seedlings
- Runner bean plants
- French bean plants
- Strawberries
- Salad plug plants
- Bedding plants for containers and borders
MyGrowPal flags late frost risks on your growing calendar. Set your UK postcode and the app adjusts planting-out dates to your local conditions — so your tender plants aren't caught out by an unseasonable cold snap.
May Gardening Jobs
Harden Off Indoor Plants
Gradually acclimatise seedlings to outdoor conditions for 7-14 days before planting out permanently.
Watering Becomes Critical
As temperatures rise, increase watering frequency, especially for new sowings and transplants. Water early or late in the day, and consider mulching to retain moisture.
Install Plant Supports
Prepare structures for climbing crops like beans and peas, and for tall flowers like sweet peas, before they get too big.
Succession Sowing
Keep sowing small batches of quick-growing crops like lettuce, radishes, beetroot, and spring onions every 2-3 weeks for a continuous harvest.
Weed Control
Weeds grow rapidly in May due to warming soil and increased light. Stay on top of weeding to prevent them from competing with your crops for nutrients and water.
Common May Sowing Mistakes
Planting Out Too Early
Cold nights can still damage tender plants like tomatoes, courgettes, and beans, especially in cooler regions. Always check local forecasts and err on the side of caution.
Not Spacing Plants Properly
Overcrowding reduces airflow, leading to increased disease risk, and limits plant growth by competing for light and nutrients. Give your plants room to thrive.
Forgetting to Water Seeds
Warm soil dries quickly in May, especially for direct sowings. Consistent moisture is crucial for germination and the establishment of young seedlings.
Ignoring Pest Pressure
Slugs, snails, and aphids become highly active in May. Regularly inspect your plants and implement preventative measures or organic controls as needed.
Using MyGrowPal to Plan May Sowing
May is one of the most demanding months in the UK gardening calendar, with rapid growth, constant planting and frequent weather changes.
MyGrowPal helps gardeners stay organised and in control by turning seed collections into structured growing plans.
Frequently Asked Questions
Is May a good month to start a vegetable garden in the UK?
Yes. May is one of the best months for direct sowing and planting out in the UK.
Can I still sow carrots in May?
Yes. May is suitable for succession sowing carrots for extended harvests.
What vegetables should I plant out in May?
Courgettes, beans, tomatoes, sweetcorn and squash can all be planted out in May.
Is it too late to sow tomatoes in May?
It is late, but still possible. Earlier sowings in March or April are preferred.
What flowers can I sow in May?
Sunflowers, cosmos, nasturtiums, zinnias and marigolds are all excellent choices.
Final Thoughts
May is a peak month in the UK gardening year, marking the transition into full outdoor growing season. With warmer soil, longer days and a wide variety of crops ready for sowing and planting, it is one of the most productive months for gardeners.
By combining direct sowing, indoor seed starting and careful transplanting, you can set up a highly productive summer garden.
And with MyGrowPal, you can keep everything organised—from seed packets and sowing schedules to planting reminders and weather alerts—so you never miss a key moment in your growing season.