May is one of the most rewarding months in the garden. The air is warm, the borders are brimming with colour, and the promise of summer is everywhere. Whether you're a seasoned grower or just finding your feet, here's everything you need to be doing this month.
Get Your Tender Plants Moving
If you've been nurturing dahlia and canna tubers in pots over the cooler months, now's the time to start hardening them off and gradually introduce them to outdoor conditions so they're ready to go in the ground by the end of May.
Tomato seedlings can begin the same process. A few weeks of acclimatising now will set them up beautifully for planting out in June. For more detailed tips, read our guide to growing tomato plants.
Sow Now, Reap the Rewards Later
May is a brilliant month for sowing. Direct-sow hardy annuals - cornflowers, Nigella and poppies - straight into borders for a glorious summer display. Sunflowers and nasturtiums are great ones to get the kids involved with, whether in the ground or in pots.
For your kitchen garden, sow pumpkin, courgette and French bean seeds in pots indoors, ready to plant out next month. And if you're already thinking ahead (as all good gardeners do), get kale started in a greenhouse and sow parsnips and Brussels sprouts directly into your vegetable beds - winter might feel far off, but it'll be here before you know it.
Basil loves this time of year too. Sow seeds in pots on a sunny windowsill - they germinate readily, so keep sowing thinly.
Tend Your Crops
Keep earthing up your potatoes as they grow. It maximises your harvest and, crucially, prevents tubers from being exposed to light, which turns them green and toxic.
Pinch out the growing tips of broad beans once the first pods begin to form. It's a simple trick that significantly reduces the risk of blackfly, which are drawn to those tender young shoots.
When harvesting rhubarb, take no more than a third of the stems from each plant - this preserves the plant's energy and ensures a healthy crop next year.
Colour Up Your Containers
Get a head start on summer by planting up pots and hanging baskets with begonias, geraniums and other vibrant bedding plants. Just keep an eye on the forecast - wait until the last frost risk has passed before placing them outside for good.
Spring Bulbs and Pruning
Once spring bulb foliage begins to yellow, you can cut it back. While you can still see where the clumps are, it's also a good moment to lift and divide any that have become overcrowded.
Turn your attention to pruning too. Early-flowering clematis such as Clematis armandii and Clematis montana should be tidied up once they've finished blooming, to keep growth in check. Spring-flowering shrubs like forsythia benefit from a post-flowering prune as well. Cut flowered shoots back to strong buds lower down to encourage next year's display.
Stay on Top of the Basics
Weeds thrive in May, so keep on top of them. Use a Dutch hoe on dry days to deal with annual weeds in borders and veg beds, and dig out perennial weeds by hand. Crucially, don't let annual weeds set seed, as the old saying goes, "one year's seeding makes seven years' weeding."
Mow the lawn regularly to keep it looking its best, but consider leaving a small patch unmown this month. It makes a real difference to bees, butterflies and other pollinators.
May rewards those who put in the effort so get outside and enjoy it. At Carpenters Nursery, we have everything you need to make the most of the season.
