Plants are generally well adapted to the seasons, but a prolonged hot spell can affect even the hardiest summer growing crops. Our garden has been no exception. Even though we were able to install permanent irrigation to our fruit trees and berries before the latest blast of heat, things are looking a bit frizzled. Young seedlings have fared the worst. Some benefited from a cover of white shadecloth. Unfortunately not enough of it to shade other plants, so there has been real leaf burn, on berries, chard, rhubarb, and other crops, and some seedling losses. If you have some, cover vulnerable plants with shadecloth or cotton sheets, or the foliage of other plants (eg a couple of leafy branches). You may need to construct something to support the shelter and remember to remove it once the hottest part of the day is over.
Avoid bare soil. The heat will bake hard any exposed soil, reduce infiltration and increase runoff when watering. Mulch bare soil, thickly.
Water deeply, overnight or early morning. Plants will also benefit from a bit of a spray directed over leaves and into the air around them, again at night or early morning, especially if humidity is low. Beware that black poly pipe and garden hoses left in the sun will heat water to scalding, so ensure you run the first stream of water away from plants. Better still, underground the poly where you can, or cover with soil or mulch, and store hoses in the shade, and wound up, to miminise heat build up.
Some plants will thrive on the extra heat if provided enough water, but many will close down stomata to prevent transpiration and loss of water through leaf surfaces. This also means photosynthesis – and growth – will be slowed or stopped. Windy conditions will compound this. Once things cool down a bit, an application of diluted biodynmaic seaweed solution will help stressed plants to recover. Maybe add some worm juice as well. Repeat again in a week or so.