August 10th, 2022 by Sarah Miles

Sunlight is vital for plant growth, but long spells of hot, dry weather can ruin all your good work. Here are some tips for keeping your plants and grass in good health through the summer, in particular in a heatwave.

Water – in the right way!

You don’t need to be an experienced horticulturist to know that plants need watering in the summer but there are ways to do it that will not only give your plants the best chance at survival but will ensure that you don’t use more water than you need:

• Time of day
  When you water your plants is as important as how often. You may think it makes sense to water when it’s really hot as that’s when the plants will be most starved of moisture, but this is actually the worst time. Watering when it’s very hot will lead to a lot of the water evaporating, meaning the plants won’t get as much as you think and it’s quite wasteful. Watering when it’s cooler in the evening means the water can penetrate more thoroughly into the soil (it’s also more pleasant for you).
• Focus on roots
  Plants absorb water from their roots so avoid the leaves and focus your watering into the soil.
• Don’t blast them
  A watering can is an ideal implement as the flow has less pressure and won’t disturb the soil. However, it’s impractical in all but the smallest of gardens so if you do use a hosepipe, put it on the lowest pressure nozzle setting so that you’re not blasting the soil and moving it around too much.
• Water source
  In the interest of sustainability, try to reuse water as much as you can. Install a water butt to collect rainwater and use whatever household water you can, such as glasses of water that didn’t get finished, the dog’s water when swapping for fresh, cooled water from cooking, or even washing up water (even with washing up liquid in, it’s fine for plants). When watering from the main supply, follow the tips above to minimise waste.
• Container plants need more
  Plants in containers will need more watering than those in borders as it’s harder for them to retain moisture – especially if planted in a porous material such as terracotta. Seal these containers with a paint-on sealant for better retention.

Provide shade

If you can shade plants from direct sun, do so. Shield using parasols or makeshift sunshades (you can buy shade cloths with stakes for this purpose) and move container plants into shaded areas.

Protect with mulch

Adding mulch to the soil will do two things: allow the soil to retain more moisture by preventing evaporation and protect roots from the heat of the sun. Apply a thick layer, approximately 7-8cm deep. A light-coloured mulch will protect from the sun better than a dark one (because dark colours absorb heat faster) and try adding vermiculite, which increases nutrient retention and aerates the soil. You can buy it on its own or add it to potting compost. Another advantage of mulch is that it helps keeps weeds at bay, providing less competition for moisture.

Care for your lawn

If your lawn is turning brown, it is not necessarily a cause for concern. Grass will go dormant to retain moisture and will discolour but should recover once it receives water again. That said, a prolonged period of dry weather (3 weeks +) could see it start to die off.

Stick to your normal mowing routine but instead of disposing of cuttings, leave them on the surface to act as mulch does in your borders. Don’t mow too short as longer grass stems will provide better shade for the roots.

Water once a week if there is a prolonged period of dry weather and apply the same principles outlined for plant watering.

Longer term solutions

There are also a few long-term strategies you can employ to protect your garden from future spells of hot weather:

• Regularly use a lawn nutrient such as iron sulphate to create stronger, healthier grass that is more resistant to weather fluctuations
• Grow drought-resistant plants such as lavender, agapanthus, geraniums, or irises that are hardier when water is scarce. Ornamental grasses that fare well in dry conditions can look nice on borders, among flowering plants.
• Plant tall, heat-resistant plants to provide shade for more delicate plants. This is known as ‘companion planting’ and can also be used to encourage pollinators and ward off pests.