How to Protect Your Garden from Heatwaves and Prevent Bolting

Heatwaves used to be the exception, now they’re fast becoming the norm. While we all love a bit of sunshine, our veg patches often feel differently, wilting leaves, thirsty soil, and worst of all, perfectly good crops bolting before harvest. But don’t despair. With a little forward planning and a few garden hacks, it’s entirely possible to protect crops from scorching temperatures and stop that dreaded bolt in its tracks.

Shade is Everything

In extreme heat, creating shade isn’t a luxury, it’s essential. We use shade netting over beds that house leafy greens, herbs, and young seedlings. For smaller areas, even an old bedsheet pegged between canes will do the job. Growing taller crops like beans or sunflowers can also provide dappled cover for more vulnerable plants like lettuce, rocket, and spinach.

Mulch to Lock in Moisture

A thick layer of mulch is like giving your garden an invisibility cloak against evaporation. We’ve had great success using straw, leaf mould, or composted bark to keep soil cool and reduce watering needs. It also protects shallow roots from the worst of the heat and keeps weeds (those water thieves!) at bay.

Water Deep and Early

Shallow watering in the midday sun can do more harm than good. Instead, we water deeply and early in the morning (or a little later in the evening) when temperatures are lower, allowing water to soak in before it can evaporate. For containers and raised beds, drip irrigation or upturned bottles can deliver water straight to the roots with minimal waste.

Harvest Promptly and Regularly

Some plants, like coriander, lettuce, and pak choi, are desperate to bolt the moment temperatures spike. Harvesting regularly can help delay bolting by encouraging fresh growth. Where possible, we pick in the cooler parts of the day to avoid stressing the plant further.

Prune for Airflow and Shade

In bushier crops like tomatoes or courgettes, strategic pruning improves airflow and can reduce heat stress. It also prevents fungal issues, which become more likely when plants are stressed and temperatures are high. At the same time, we’re careful not to over-prune, we want to keep some foliage to shield fruit from sunscald.

Resow Little and Often

Rather than planting one big batch of heat-sensitive crops, we prefer to sow small amounts regularly. That way, if one lot bolts or struggles, we’ve got backups on the way. Succession sowing also means we’re not relying on one moment in the season for our entire harvest.

Heatwaves are tough, but they don’t have to wreck a veg patch. With a bit of clever shading, mulch, and thoughtful planting, we can keep our gardens productive, even when the sun is relentless. And when bolting does happen (because it will, now and then), we treat it as a nudge to resow, regroup, and keep growing.