May in the Garden | Hortiwool

If April is the month the garden wakes up, May is the month it really gets going. The risk of frost is (hopefully) behind us, the days are noticeably longer, and there's a warmth to the soil now that makes everything want to grow. Including the weeds, but we'll get to those.

Here at Hortiwool, May always feels like the most exciting month of the growing year. The greenhouse starts to empty out as plants make their way into the ground, the veg patch fills up fast, and the borders begin to take on some real colour. There's a lot to do, but it's the good kind of busy.

For now, here's what we're growing this May, how we're using our Hortiwool Garden Pads throughout the season, and a bumper list of jobs to get through while the growing conditions are at their very best.

5 Vegetables to Plant in May

1. Courgettes

May is courgette month, without question. Once you're confident the last frost has passed, courgettes can go outside, and they'll reward you more generously than almost anything else in the veg patch. Give them plenty of space, at least 90cm between plants, and enrich each planting hole well before they go in.

This is one of our favourite places to use a Hortiwool Garden Pad. Tuck one into the base of the planting hole before you add the plant, then backfill with compost around it. As the wool breaks down over the coming months it releases nitrogen slowly into the soil and courgettes are incredibly hungry plants that will absolutely make use of every bit of it. It also acts as a moisture reservoir at root level, which matters more than you might think once summer hits and the soil dries out quickly between waterings.

2. French Beans

French beans are one of the most satisfying things you can grow in May. Sow directly into warm soil, about 5cm deep and 15cm apart, and they'll germinate quickly and grow fast. Climbing varieties like Cobra need canes or a wigwam to scramble up; dwarf varieties like Safari are self-supporting and brilliant for containers or smaller plots.

Once pods start forming, consistent watering is everything. Inconsistent moisture at that stage leads to tough, stringy beans, a shame when the fresh-picked ones are so good. If you're growing in raised beds, laying a Hortiwool Garden Pad beneath the topsoil before planting acts as a slow-release water reservoir, absorbing excess moisture and releasing it back gradually during dry spells. It's particularly useful if you're going away in summer and worried about the garden drying out in your absence.

3. Tomatoes (Outdoors)

If you've been growing tomatoes on the windowsill or in the greenhouse, May is the month they can finally move outside, or into their final greenhouse position if you're growing under glass. Plant into a warm, sheltered spot and bury the stem slightly deeper than it was in its pot; tomatoes will put out roots all the way along a buried stem and be stronger for it.

For tomatoes going into containers or grow bags, place a Hortiwool Garden Pad at the base of the pot before adding compost. The pad holds water like a sponge, retaining up to 30% of its own weight, and releases it steadily back to the roots, which means less watering panic during hot spells and less risk of the erratic wet-dry cycle that causes blossom end rot. As the wool slowly breaks down it feeds the compost naturally too, which busy fruiting plants appreciate enormously.

4. Salad Leaves

If you want a continuous supply of salad right through summer, May is when you establish the habit. Rather than one big sowing, do a short row every two to three weeks and you'll have fresh leaves from now until October. Cut-and-come-again varieties, mixed salad leaves, rocket, spinach, and mustard greens, are ideal. They're also brilliant in containers or window boxes if you're short on space.

For salad in pots, tuck a piece of Hortiwool Garden Pad into the base of the container before filling with compost. Salad leaves are shallow-rooted and can dry out alarmingly fast in warm weather, the pad helps retain moisture at that critical zone and keeps growth consistent rather than stressed. You can also cut a pad to size to fit any shape of container, which makes it adaptable to whatever you're growing in.

5. Sweetcorn

Sweetcorn is one of those crops that sounds complicated but really isn't, as long as you remember one thing: it's wind-pollinated, so it must be planted in a block rather than a row. Plant in a grid, at least four plants by four and the pollen will transfer between them properly. Sow into pots now or direct sow outside in late May once the soil is genuinely warm.

The gap between picking and eating should be as small as possible. Sweetcorn starts converting its sugars to starch the moment it leaves the plant, so grow it, pick it, and eat it that same day for the full experience. Worth every square metre of space.

5 Flowers for the Perfect Summer Garden

1. Cosmos

If you grow one flower from seed this May, make it cosmos. It's fast, generous, beautiful, and genuinely doesn't seem to mind if you're occasionally neglectful. Sow directly into a sunny border or into pots and it'll flower from July right through to the first frosts. Varieties like Purity (white), Sensation Mixed, or the deep crimson Dazzler are all brilliant. It's also an exceptional cut flower, the more you pick, the more it produces.

2. Sunflowers

May is a great time to direct sow sunflowers outside. They grow fast in warm conditions and produce something that's joyful in a way that's difficult to articulate. Grow in a sheltered spot, tall varieties can catch the wind badly, and push a cane in early to save disturbing roots later. Giant varieties like Titan are enormous fun, but shorter branching varieties like Velvet Queen or Lemon Queen produce multiple blooms and look extraordinary in a border or as cut flowers.

3. Wildflowers, For the Bees

A wildflower patch doesn't need to be large to make a real difference to local pollinators. Even a square metre sown this month with cornflowers, poppies, oxeye daisies, and field scabious will be alive with bees and butterflies by midsummer.

The key to success is poor soil, wildflowers evolved on lean ground and will be outcompeted by grasses and weeds if conditions are too fertile. Rake the surface to a fine tilth, scatter seeds thinly, and rake lightly again to make good contact with the soil. Then leave it alone.

If you're sowing into a lawn area, mow the grass short first, rake out as much thatch as possible, and scatter seed directly onto the surface. One tip worth knowing: a Hortiwool Garden Pad placed loosely over freshly sown wildflower seed offers some protection from birds in those vulnerable first days while helping retain moisture during germination. Once seedlings are showing, remove the pad and add it to your other plants or compost heap where it will continue to break down.

4. Sweet Peas

If you sowed sweet peas earlier in the year, May is the month they really start to perform. Get them onto their supports now and pinch out growing tips if you haven't already, to encourage bushy, branching plants with more flowers. The most important thing with sweet peas is relentless picking, the moment you allow seed pods to form, the plant slows dramatically. Pick every few days, even if it just means bringing stems indoors, and they'll flower right through summer.

For sweet peas in containers, a Hortiwool Garden Pad at the base of the pot keeps moisture consistent without waterlogging, sweet peas hate sitting in wet compost but equally hate drying out completely between waterings. The pad takes a lot of that guesswork away.

5. Zinnias

Zinnias are the flower we wish more people grew in the UK. Incredibly easy, extraordinarily colourful, and they thrive in the kind of warm summers we increasingly seem to be getting. Sow directly where they're to flower in May, or start in individual pots on a warm windowsill, they don't like root disturbance, so avoid modules. The Benary's Giant series produces huge blooms in extraordinary colours; Zahara is more compact and excellent in containers. Like cosmos, the more you cut, the more they flower.

Jobs to Get On With in May

May is the month the to-do list gets properly serious. Here's a thorough run through everything worth doing this month:

Harden off indoor plants - Anything started indoors, tomatoes, peppers, courgettes, squash, dahlias, needs to be gradually introduced to outdoor conditions before it goes out for good. Put trays outside during the day, bring them in at night, over one to two weeks. It sounds fiddly but plants that have been hardened off properly establish far more strongly than those that haven't.

Pot on seedlings that are getting rootbound - Roots circling the base of a module or small pot are a sign that a plant needs more space urgently. Don't leave them sitting too long, a plant that's been cramped for too long takes time to recover even after potting on. When repotting, tuck a Hortiwool Garden Pad into the base of the new container before adding compost. As it breaks down it releases nitrogen naturally, giving newly settled plants a gentle feed without any chemical input.

Mulch beds and borders - With the soil warming and the drier months approaching, now is exactly the right time to mulch. A good mulch layer conserves moisture, suppresses emerging weeds, and improves the soil as it breaks down. Hortiwool Garden Pads work brilliantly laid around plants as a compostable mulch; place them around the base of plants, cover with a thin layer of bark or compost if you prefer a tidier finish, and let the wool do the work.

Use Hortiwool to deter slugs and snails - May is peak season for slugs and they will go for your best plants first, without fail. The natural fibres of Hortiwool Garden Pads are coarse enough to irritate the soft undersides of slugs and snails, making them reluctant to cross. Place strips or sections around vulnerable plants; lettuce, hostas, strawberries, young courgette plants, as a chemical-free, pet-safe, child-safe barrier.

Tie in climbing plants. Roses, clematis, wisteria, and sweet peas are all putting on growth rapidly now and will get away from you quickly if you don't keep up. Check supports, tie in new growth, and train stems in the direction you want them to go while they're still flexible.

Set up your hanging baskets. May is the traditional month for planting up hanging baskets, ready to go outside after the last frost. Instead of plastic liners, try Hortiwool Hanging Basket Liners, they hold water far more effectively than synthetic alternatives, meaning less watering on hot days, and they're 100% compostable at the end of the season. No plastic, no waste.

Feed containers and pots weekly. Plants in pots can't access nutrients from the wider soil, so once growth gets going in May they'll need a regular liquid feed. Start now and keep it up weekly through the growing season.

Sow herbs. May is a brilliant time to sow basil, coriander, dill, and fennel from seed. All of them want warmth and will sulk in cold conditions, so wait until the soil is genuinely warm and pick a sheltered spot. 

Deadhead spring bulbs but leave the foliage. Tulips and daffodils that have finished flowering should have their spent flower heads removed, but the leaves need to stay until they've died back naturally. The foliage is feeding the bulb for next year, fold it over neatly if you can't bear the look of it, but don't cut it.

Water in the evenings. As temperatures rise through May, watering in the evening rather than the morning reduces evaporation significantly and means more water actually reaches the roots. For pots and containers, Hortiwool Garden Pads at the base help retain what goes in, meaning you need to water less frequently even during warm spells.

May is the month everything comes together. After months of sowing, waiting, and hoping, the garden finally starts to deliver and there's really nothing quite like it.

We'd love to see what you're growing and planting this May. Tag us on Instagram @wearehortiwool or send us a message!

And if you want to try Hortiwool Garden Pads or our Hanging Basket Liners this season, you'll find everything in our full range here.

Happy growing, from all of us at Hortiwool. 🌱