May Gardening Jobs: Sowing, Planting and Preparing for Summer
By Alicia Paaso - Gardenscape Sales Team/RHS Level 3 Horticulturalist
May is a gorgeous spring month, as gardens transition from spring bulbs to summer-flowering perennials. It’s an exciting time for gardeners, with major events such as the RHS Malvern Spring Festival and the RHS Chelsea Flower Show taking place this month. Flowers such as alliums, wisteria and peonies burst into bloom, bringing vibrant colours and fragrance to gardens. With summer just around the corner, May is a busy month for sowing, planting, and general garden maintenance.
Don’t panic if you haven’t started sowing your vegetables yet, as May provides ideal conditions for seed germination thanks to its longer, warmer days. Many crops can still be sown outdoors, including lettuce, rocket, peas, spinach and beetroot. A fine seed and cutting compost is ideal for sowing smaller seeds such as lettuce and rocket in seed trays. Larger seeds like beetroot and peas can be sown directly outdoors or into multipurpose compost in containers. If you have seedlings that were started indoors, they should be gradually hardened off outside this month before planting them outside permanently.
May is also the last opportunity to complete your spring lawn care routine. If you haven’t re-seeded your lawn yet, aim to do so in May before temperatures rise too high. Most lawns will benefit from scarifying and aerating before seeding, helping to remove dead grass and moss while reducing soil compaction. Once prepared, choose a cooler day with adequate soil moisture for seed germination. To boost growth, finish by applying a spring and summer lawn feed for lush growth.
This is also a great month to plant up summer hanging baskets, which provide an easy and impactful way to bring colour into any outdoor space. Combining perennials, annuals, and trailing plants creates beautiful, long-lasting displays full of texture and structure. Popular and suitable plants for hanging baskets include creeping Jenny, petunias, lobelia, verbenas, and geraniums. Tomatoes and strawberries can also grow well in hanging baskets, making them ideal for edible displays, while helping to keep fruit away from slugs. When planting your baskets, use a compost with a high water-holding capacity to prevent them from drying out during hot days. John Innes Multipurpose is an excellent choice, providing both moisture retention and essential nutrients. Once planted, water baskets thoroughly, and continue watering regularly throughout the growing season, especially during hot spells.
There are plenty of maintenance jobs to tackle this month to prepare your garden for summer. Climbing plants such as wisteria, clematis, and climbing roses begin to put on vigorous growth at this time of year. Make sure to tie new stems securely to their supports to prevent damage and guide their growth. Continue earthing up potatoes by mounding soil around their stems as they grow, which protects developing tubers from sunlight and prevents them from turning green. Regular mowing every one to two weeks will help encourage a denser, healthier lawn. Alternatively, you could leave your lawn uncut this month and take part in ‘No Mow May’ to support pollinators and encourage biodiversity in the garden. Finally, keep on top of weeds and regularly check plants for pests so that any problems can be dealt with before they become serious.
Enjoy your May gardening!