Rain
The middle of May can be one of the driest times of year, particularly in the south, and most gardens will begin to dry out.
Initially, this is a benefit because the soil will reach an ideal consistency for seed sowing. However, as drying continues, there may be insufficient water to keep the seedlings going, especially in dry regions such as southeast England and East Anglia.
Use water butts to collect rainwater. Open rain-catchers are a start, but fixing the butt to your down-pipe will enable you to collect rainfall from your house or shed roof as well. Target your watering to when and where plants need it - often at fruit set and fruit swelling times, or coming up to flowering.
Sunshine
Plenty of strong sunshine should ensure that plants grow rapidly this month. In Scotland and Wales, May averages as the sunniest month of the year, with around 170-180 hours of sunshine. In southwest and south-central England over 200 hours can be expected, but light levels will increase further towards mid-summer.
The Midlands follow a similar pattern, but with on average about five to 10 fewer hours of sunlight than southern England.
Temperature
May is very changeable. With hot and cold temperatures following each other in rapid succession, the risk is that warmer weather will result in soft growth, which is then susceptible to scorch when frosts and cold, drying winds return.
Make sure you harden off your bedding plants carefully to ensure they don’t suffer when making the transition from greenhouse to garden.
Ventilate your conservatory or greenhouse in the daytime to prevent temperatures soaring in the sunshine. Be ready to apply shade paint, netting or use the blinds.
Wind
Generally the winds are now much lighter, and even Atlantic depressions are fairly weak. The only blips are thunderstorms, which bring squally winds and damaging hail that can pockmark new foliage and flowers.
Precious plants can be protected with fleece, but it is hard to predict when storms will arrive. It is also worth ensuring that herbaceous borders are well staked, to prevent gusts from flattening your perennials.