Watering plants during a heat wave? Here's how to do it right
Your plants need water. Especially during heat and prolonged drought, they cannot get enough water from the soil themselves (and potted plants certainly cannot!). However, you want to be frugal with water during dry periods. How do you help your garden get through the drought and heat? This is how you deal with watering wisely.
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In warm weather, it is best to water your plants at cooler times: early in the morning or in the evening when the sun is no longer shining on your garden. This way, the water will evaporate less quickly and has more time to reach the roots. Also make sure to water your plants when the sun is not shining on them, because drops on the leaves can act as a magnifying glass and burn leaves in combination with sunlight.
In warm weather, water evaporates faster and that is why sprinkling is often less effective than giving it a good watering with a watering can. If you still want to use a sprinkler, it is best to do so early in the morning or (later) in the evening. When it cools down a bit, the water will evaporate less quickly and there is a greater chance that your plants can absorb the water.
The first signs of water deficiency in a plant are drooping stems and leaves. After you water the plant, it usually recovers. However, if it is dry for a long time, the small root hairs that are supposed to absorb the water die. A severely withered plant needs time to grow new root hairs before it can recover.
Are plants drooping after a hot day? Then you don't need to water them right away. Instead, leave them alone overnight and check the next morning. Are they still drooping? Then water them. Have they recovered? Then there is nothing wrong and extra water is not necessary.
Overwatering can cause the same symptoms as underwatering! The easiest way to find out which of the two is the problem is to simply stick your finger a little way into the soil. It’s not very scientific, but it is effective. Even if the top layer is dry, it can still be moist enough underneath. In that case, do not water for the time being.
It is better to give a lot of water at once than small amounts, especially for perennials in the open ground – otherwise the water evaporates before it reaches the roots. By not watering too often, you encourage plants to root deeper. So give them a good splash of water once and then wait a while.
These guidelines will help you water your plants in hot weather:
If water is scarce, prioritize seedlings , cuttings, and young plants. Potted plants , both in the greenhouse and in outdoor flower boxes, also need plenty of water. Newly planted trees and shrubs should also be watered well. Pay special attention to conifers and evergreens, as they can burn if they don’t get enough water!
These plants need water every two days:
- Tomatoes : Water the plants very regularly once they are in bloom and the fruits are growing.
- Cucumbers and courgettes : These plants are very thirsty.
- Broad beans: When the pods swell during drought they really need plenty of water.
- Tree Ferns: These plants do not like drought; direct water towards the trunk.
- Lobelia cardinalis : Cardinal lobelia is a bog plant, so provide boggy soil.
Plants with shallow roots, such as bedding plants, large subtropical plants with thin leaves and ferns in the open ground need a good splash of water once a week. Marsh plants and moisture-loving perennials such as plantain lilies ( Hosta ) are very sensitive to drought. When vegetables and herbs are too dry, they quickly bolt (they start to flower). And soft fruit bushes lose their ripening fruit.
These plants need water once a week:
- Cabbage: White cabbage, cauliflower and Brussels sprouts.
- Lettuce: Especially when you want to harvest more often from the same sowing.
- Spinach: Tends to bolt. In drought conditions the crop fails.
- Celery: Needs plenty of water, twice a week in extreme drought.
- Hydrangea : These plants wither quickly if they don't get enough water.
Many plants can normally do without extra water. However, during long periods of drought, they will need a bit more water. It is better to give a large amount once every two weeks than a little bit more often. Also give shrubs with shallow roots extra water, such as fruit bushes, camellias and rhododendrons .
These plants need water once every two weeks:
Some parts of the garden are best left untouched to prevent them from becoming dependent on the watering can or sprinkler. Keep the lawn dry so that hardy grasses and clovers survive. Mature trees, shrubs, hedges and wood edges do not need watering. Large traditional fruit trees need long roots to survive.
These plants do not need extra water:
- Cordylines: The strong leaves of this palm-like plant retain water.
- Verbascum : Torch thrives in dry soil in places where other greenery has difficulty.
- Vinca :Periwinkle is very strong and is best ignored.
- Aeonium : This succulent, like other succulents , stores enough water to survive.
- Agave : This extremely strong plant needs nothing more than an occasional rain shower.
Tip! Is your plant not listed? Then take a look at our plant guides , where you will find more information about caring for your plants.
The answer to this question depends on various factors and there is therefore no single answer. Fortunately, you can find out for yourself by looking at what these factors are in your garden. Plants in (partial) shade generally need less water than plants in full sun. A soil that retains moisture well is a blessing on hot days (clay soil for example) and other soil can be mulched to retain more moisture.
Plants in pots can store less water due to their limited surface area and you will have to water them more often than plants in the ground and a plant with large leaves will keep out a lot of rain and will probably be a bit more thirsty. The same applies to garden areas with many trees, where in addition trees also absorb a lot of water. If your plant is against or near a wall, it may be in the so-called 'rain shadow', namely that the rain is often kept out by the wall and the soil dries out as a result. In that case too, it is good to water your plant a bit more or more often.
