The morning watering is better because the leaves dry faster, but the water has less time to reach the soil before it gets too hot. What’s the solution?
All living organisms need water for chemical reactions to occur in their cells, which provide energy. Plants need water as well to transport nutrients from the soil into the growing cells. The water is drawn to replace the water that leaves through stomata, which are breathing holes in leaves. These are required for gas exchange during photosynthesis – oxygen in and carbon dioxide out. Photosynthesis is a process that fixes a large amount of carbon dioxide in high light conditions. On hot days, it is important that plants lose water.
When plants are short on water, they close their stomata. Photosynthesis is stopped and photorespiration takes over – a process which releases carbon dioxide. Desert plants can overcome this problem by breathing during the night, storing the carbon dioxide and then releasing it to photosynthesis in the morning when the stomata open. In our gardens, very few plants can do this.
plants begin to wilt as the shortage of water becomes more severe. This is temporary wilting, and plants can quickly recover when water becomes available. Further drying can cause permanent wilting and even death to parts or the entire plant. Some plants survive drought by dying below the ground. This is true for garden bulbs like bluebells and tulips. Some plants may lose their leaves, while others will only survive as seeds.
Avoid the full sun.
It is widely accepted that plants in full sunlight should not be irrigated. Nearly a decade ago, the notion that moist leaves in full sun cause scorch on plants was disproven. There is no doubt about the fact that watering plants in full sunlight is not efficient, as most of it will disappear before reaching the soil.
Watering early in the evening is best for the hot, breezy weather. The plants will have enough time to dry, and the roots can still absorb water overnight. If you are watering in the morning, start early before the sun comes up.
Some cacti can survive for up to two years without any water. Pexels
It is important to water the entire root zone. Regularly lightly watering plants causes them to develop shallow roots and become less drought-resistant. Water plants deeply but only occasionally. Please don’t allow the soil to dry out, as it will be harder to moisten completely.
Water the soil instead of the plant. Be careful not to create a hard surface on the ground. Mulch (wood chips or organic compost) will protect your soil and help to keep it moist. But beware of snails.
Overwatering is a serious problem.
The soil can be too dry for plants. While the top layer of the soil may be dry, it might not be 15-20cm below the surface. The roots of most plants are deeper, so they could be pulling water up that you cannot see.
If the plant does not appear to be wilting, it is likely that there is water available. Some plants, such as herbaceous ones, will wilt to conserve moisture in the full sun but will rehydrate when the temperature drops later in the day. The lupins in my garden are doing this daily at the moment, but are deeply rooted. They do pick up later in the day.
If possible, place plants in shade to reduce water consumption. Shutterstock
Containerised plants must be well watered. It would help if you wet the containerized plants in the evening. Water thoroughly, and only if necessary. At the moment, greenhouse tomatoes may need to be watered daily. If you’re growing carrots, make sure that the soil is moist. Otherwise, you could end up with a split root.
Don’t worry if your lawn looks a bit dry. Grass can grow back quickly after rain. Avoid excessively walking on a bare lawn. This will result in bald patches because of the combination of drought and heavy use.
Enjoy your garden during the summer heat, but don’t forget that plants also enjoy some shade and a cool drink.