May is one of the busiest and most rewarding months in the gardening calendar. The soil is warming up, the risk of frost is fading in many parts of the country and gardens suddenly burst into life with fresh foliage, blossom and rapid growth.
Whether you have a tiny courtyard, a suburban lawn or a sprawling cottage garden, May is the month when your outdoor space starts to shape how it will look all summer.
The key to successful gardening in May is staying ahead of the season. Small jobs tackled now, from mulching borders and supporting plants to sowing seeds and feeding hungry crops, will pay off massively in June and July.
Here’s our practical guide to gardening in May and the jobs worth focusing on this month.
1. Tidy, Feed and Mulch Your Borders
What to do:
After months of winter rain and early spring growth, many borders are hungry for nutrients. One of the best things you can do in May is improve and replenish your soil.
Adding compost, manure or soil conditioner helps retain moisture, suppress weeds and improve soil structure. Think of your soil as a living ecosystem rather than simply “dirt”.
If your borders tend to dry out quickly in summer, apply a 5–7cm layer of mulch around plants now. This helps lock in moisture and reduces watering later in the season.
Useful products to purchase:
– Peat-free compost
– Soil conditioner
– Organic manure
– Mulch or bark chips
Our favourites this month include RocketGro Multi Purpose Compost, made in Somerset, along with Levington Soil Conditioner and Levington Organic Manure.
2. Plant Summer Bedding
What to do:
May is the traditional time to plant colourful summer bedding displays.
Petunias, begonias, lobelia and marigolds can usually be planted outdoors safely by mid-May in southern England. In colder or more exposed areas, it is worth keeping an eye on overnight temperatures and waiting a little longer if frost is still possible.
Before planting, remember to harden off greenhouse-grown plants by putting them outside during the day and bringing them back in at night for around two weeks. This helps prevent shock and encourages stronger growth.
Helpful tips:
– Plant in groups of odd numbers for a more natural-looking display
– Water thoroughly after planting
– Deadhead regularly throughout summer to encourage more flowers
Hanging baskets and patio pots can also be refreshed now for instant colour around the garden.
3. Support Plants Before They Flop
What to do:
Peonies, delphiniums and many tall perennials put on rapid growth during May and can quickly become top-heavy.
The best time to install supports is before plants start leaning or collapsing. This allows stems to grow naturally through supports and avoids damaging roots later.
Useful items to purchase:
– Bamboo canes
– Garden twine
– Plant supports and hoops
– Soft ties
Putting supports in place early can make a huge difference to how borders look later in the summer.
4. Sow Flowers and Wildflowers
What to do:
May is an excellent month for sowing hardy annual flowers and wildflower seed mixes directly into the ground.
Wildflower patches are one of the easiest ways to support bees, butterflies and other pollinators throughout the summer months.
For best results, sow onto cleared bare soil and water gently during dry weather until seedlings establish.
Helpful tips:
– Choose sunny areas where possible
– Avoid overly rich soil for wildflowers
– Leave some lawn areas longer as part of No Mow May
Even a small patch of longer grass or wildflowers can make a real difference to local wildlife.
5. Get the Lawn Under Control
What to do:
Lawns grow rapidly in May and often need mowing once a week.
Modern gardening trends increasingly encourage a balance between tidy lawns and wildlife-friendly spaces. A good compromise is to keep main areas neat while allowing one corner to grow longer and wilder.
Top lawn jobs for May:
– Edge borders neatly
– Reseed bare patches
– Remove weeds
– Feed if growth looks weak
– Raise mower blades during dry weather
Helpful tips:
Avoid cutting grass too short during warm spells, as slightly longer grass retains moisture better and copes with heat more effectively.
6. Start Feeding Tomatoes
What to do:
If you are growing tomatoes in a greenhouse, conservatory or sunny patio, May is the month when regular feeding becomes important.
Once flowers appear, switch to a high-potash tomato fertiliser and feed weekly.
Useful items to purchase:
– Tomato feed
– Plant supports or canes
– Grow bags or greenhouse pots
We recommend Levington Tomorite, which is also excellent for feeding many other flowering and fruiting plants around the garden.
Helpful tips:
Feed little and often rather than using strong doses occasionally.
7. Watch Out for Slugs
What to do:
Warm evenings and fresh young growth make May prime slug season.
Hostas, dahlias and tender vegetable seedlings are especially vulnerable, so it is worth keeping an eye out early before damage becomes severe.
Wildlife-friendly slug control ideas:
– Copper barriers
– Wool pellets
– Hand-picking at dusk
– Encouraging frogs and hedgehogs
Many gardeners now prefer wildlife-friendly methods rather than harsh chemicals, and we have a wide selection available in store.
8. Don’t Forget Containers and Hanging Baskets
What to do:
Plants in containers dry out much faster than those growing in borders, especially once temperatures begin to rise.
Water consistently and begin feeding regularly once plants are actively growing.
Helpful tips:
A simple trick used by experienced gardeners is combining:
– A tall “thriller” plant for height
– Bushy “filler” plants for fullness
– Trailing “spiller” plants around the edges
This creates fuller, more professional-looking displays with surprisingly little effort.
Useful items to purchase:
– Hanging baskets
– Patio containers
– Multi-purpose compost
– Slow-release fertiliser
– Watering cans and liquid feeds
9. Make Time for Wildlife
What to do:
Gardens are at their busiest in May, with pollinators, birds and amphibians all becoming more active.
Leaving small areas slightly wilder can help create shelter and food sources for wildlife without sacrificing the overall appearance of your garden.
Wildlife-friendly ideas:
– Leave a patch of longer grass
– Add pollinator-friendly flowers
– Provide shallow water sources
– Avoid pesticides where possible
Even simple changes can help encourage a healthier and more balanced garden ecosystem.
May gardening is really about momentum. The more small jobs you stay on top of now, the easier the summer becomes.
Spend time feeding the soil, supporting fast-growing plants and creating space for wildlife, and your garden will reward you with colour, scent and life for months to come.
So pop on your gardening gloves and get out into your garden this May.
