As many of you will be aware, we are about to experience our third heatwave of 2026. Although we might enjoy the warm sunshine, our plots can suffer so here are some tips to help your plot thrive despite the challenging temperatures.
Water Properly, Not More Often.
One of the biggest mistakes allotment holders make during a heatwave is giving plants a little water every day. Frequent, shallow watering encourages roots to stay near the surface, making plants more vulnerable to drought.
Instead, water deeply and less frequently. A thorough soaking encourages roots to grow deeper into the soil where moisture levels remain more consistent.
Early morning is usually the best time to water, as less moisture is lost through evaporation. Evening watering can also work well, although wet foliage left overnight can occasionally encourage fungal problems.
Pay particular attention to newly planted seedlings, container-grown plants, courgettes and cucumbers as well as bean and peas.
Mulch Your Beds to Lock in Moisture
Applying mulch is one of the most effective ways to protect an allotment during hot weather.
A layer of organic material helps to reduce evaporation, keep the soil cool and suppressed weeds that compete for water.
Check out this very informative article about mulching at Mulch, glorious mulch
Give Vulnerable Crops Some Shade
Not every vegetable enjoys intense sunshine. Leafy crops such as lettuce, spinach and rocket can quickly bolt or become bitter during hot weather. Young seedlings are also particularly vulnerable. Temporary shade can make a huge difference. You can create shade using shade netting, garden fleece old net curtains or even use an old umbrella or parasol.
Providing shade during the hottest part of the afternoon can significantly reduce stress on sensitive plants.
Keep an Eye on Containers and Raised Beds
Containers and raised beds warm up and dry out much faster than open ground.
Plants growing in pots may need watering once or even twice a day during exceptionally hot weather. Raised beds, especially those filled with light compost, can also become surprisingly dry.
If possible, move containers into partial shade and group pots together to reduce moisture loss. Adding a layer of mulch will also be beneficial and check moisture levels daily.
Harvest Little and Often
Harvesting regularly can help reduce the stress placed on plants.
Leaving vegetables such as courgettes, beans and cucumbers to become oversized forces plants to divert more energy into maturing fruit rather than producing new growth.
Regular harvesting encourages continued cropping and reduces overall strain during difficult conditions.
Watch Out for Bolting
Bolting is one of the most common problems during a heatwave.
Plants such as Lettuce, Spinach, Rocket, Coriander and Spring onions may suddenly produce flowers and go to seed. Unfortunately, once a plant has bolted there is usually little that can be done.
The best way to prevent bolting is to water consistently and try and provide shade.
Succession sowing every few weeks also ensures you always have replacement crops available
Don’t Forget Wildlife
Heatwaves don’t just affect your vegetables.
Pollinators, birds and beneficial insects also struggle during prolonged dry periods.
Adding a shallow dish of water, keeping a pond topped up, or leaving a small muddy area for insects can make a big difference to the wildlife that helps keep your allotment healthy.
