Our green-fingered expert Adam Kirtland reveals his top tips for making the most of May – a month of growth and colour!

May is here at last, and the garden is finally hitting its stride. The days are longer, the sun has a bit more warmth to it, and everything seems to be growing at double speed. The first real signs of summer are creeping in, and after months of careful planning and early sowing now is the time to get stuck in and enjoy it.

With the last frosts behind us, there is plenty to be getting on with. Dahlias can go into the ground, borders can be topped up with new plants, and seeds can be sown directly where they are to flower. The vegetable garden is also in full swing, with potatoes needing attention and other crops getting well established. It is a busy time, but an exciting one too. So, let’s grab our tools, head outside and make the most of May. 

Planting Out Dahlias

If you have been looking after dahlia tubers indoors or in the greenhouse, now is the moment to plant them out. These bold, beautiful flowers love a warm, sunny spot with free-draining soil, and getting them in the ground in May gives them plenty of time to settle in before they start flowering later in the summer.

Dig a hole deep enough to comfortably fit the tuber, making sure the growing tip sits just below the surface. Give them a good watering after planting and, if slugs are a problem in your garden consider adding some organic slug deterrents. Dahlias can be a bit floppy when they get going, so it is worth staking them early to avoid damage later on. A fortnightly feed with a high-potassium fertiliser, such as tomato feed, will help keep them strong and full of blooms right through to autumn. 

Sowing Poppies and Filling Gaps

May is a brilliant time to scatter annual flower seeds straight into the soil. Poppies, cornflowers and nigella are all easy to grow and fantastic for filling in gaps in borders. They will bloom in just a few weeks, adding bursts of colour and attracting pollinators to the garden. Simply rake the soil lightly, scatter the seeds and water them in. No fuss, no complicated techniques – just let nature do the rest.

If your borders are looking a little sparse, now is also the perfect time to add in summer bedding plants or perennials. Salvias, cosmos and marigolds are all great choices that will flower reliably for months. When planting, make sure to water them in well and keep an eye on any late cold snaps, as May can still throw in the odd chilly night. A layer of mulch around new plants will help retain moisture and suppress weeds, giving them the best possible start. 

Earth Up Your Potatoes

If you are growing potatoes, May is the month to keep on top of earthing them up. As the plants grow, gradually mound soil around the base, covering the lower leaves but leaving the top growth exposed. This encourages strong tuber development and stops the potatoes from turning green and becoming inedible.

It is also important to keep your potatoes well watered, especially if the weather is dry. They need a steady supply of moisture, particularly as they start forming tubers. A deep soak once or twice a week is far better than little and often, as it encourages strong root growth. If you are growing potatoes in containers, make sure they have good drainage and do not let them dry out completely.

A useful tip for keeping your crop healthy is to mulch around the plants with straw or grass clippings. This helps the soil retain moisture and reduces the risk of blight by keeping the leaves drier. With a bit of care now, you will have a tasty harvest to look forward to in the months ahead. 

Final Thoughts

May is a month of real momentum in the garden. Everything is growing at pace, and the jobs you do now will shape how your garden looks for the rest of the year. Whether it is planting out dahlias, sowing annuals or tending to your vegetable patch, there is plenty to keep you busy.

But amongst all the hard work, do not forget to take a step back and enjoy it. Watch as new shoots emerge, listen to the bees buzzing around the flowers and soak up the sights and scents of the season. The groundwork of spring is behind us, and now we get to enjoy the rewards of all that effort. Happy gardening!