Expert Shares Essential May Gardening Jobs To Protect Summer Growth And Plant Health

It’s a big seasonal shift into the summer phase, so if you skip certain tasks, you could risk permanently limiting yields, flowering and plant health.

1. Harden off tender crops

Mid-to-late May is the time for indoor-grown plants to move outside. Think of hardening off as ‘toughening up’ – getting them acclimatised to the outdoors. Do this by gradually increasing their exposure for a few more hours each day, over a week or two, before planting them out.

Wait any longer and you’ll reduce the window for crops. Skip it entirely, and the shock of being plunged straight into the ground could stall growth or even kill your plants.

2. Clear the decks

Clear the leaves and blossom scattered by spring storms. Composite decking such as Trex® is low-maintenance and durable, but it’s still important to remove leaves as they can become a mould magnet – and while Trex provides a non-slip surface, soggy leaves do not!

3. Thin seedlings – properly!

This job directly affects yield for carrots, beetroot or lettuce, to name just a few. Overcrowded seedlings compete for light and nutrients, growing thin and spindly and more vulnerable to pests. We’re talking about tiny carrots with twisted roots, disappointing lettuce that could flower too early, and beetroot that stays stunted and small.

Check seedlings have their first set of “true” leaves – the ones that grow after the initial leaves from the seed – and soften the soil with water. Instead of pulling them out of the soil, use scissors or fingernails to snip the smaller seedlings at soil level. Leave the recommended spacing for each crop. For example, carrots should be 5-8cm apart in the row, with rows spaced 15-30 cm apart.

4. Check atmospheric lighting

As the nights grow longer, May is the perfect time to check over your outdoor lighting. Whether you have integrated lights built into your decking or standalone fixtures dotted around the space, give everything a quick once-over to make sure it’s clean, working, and ready to glow. Replace any faulty bulbs, wipe away dirt or algae and check that wiring or solar panels are in good condition. A little attention now means you’ll be ready to relax until late in the evening.

5. Put supports in place

This is a time-sensitive job that needs doing before roots are established and stems have grown long. Introducing supports when plants are well on their way can harm the roots and result in unruly, untidy plants.

Adding supports early keeps plants upright, improves airflow and makes harvesting easier.

For peas, push a row of sticks into the ground for the tendrils to cling and grow up. Tomatoes will also be happy with a sturdy cane per plant, but you could also use string supports attached to an overhead frame. And for beans, use bamboo canes tied together at the top to create an A-frame for the plants to weave their way up. Be gentle when tying the plants and use soft twine or specialist plant ties.

6. Think twice before trimming hedges!

May falls right in the middle of bird nesting season and disturbing an active nest is an offence under the Wildlife & Countryside Act 1981. So before trimming a hedge, watch for birds visiting it or listen for chicks. If you spot any signs of activity, don’t touch it until the young have fledged.

If in doubt, wait. The ideal time for hedge cutting is October to February, outside nesting season.

7. Mind how you mow

As lawns dry out, this is the perfect time to drop the blade height on the mower and get that crisp, short cut – just in time for the cricket season! This can’t be done immediately after winter as it will shock the lawn, so May is the month to do it.

In summer, if we have a drought, then you need to raise the mower up again to protect the grass.