As global temperatures rise and heat waves become more frequent, gardeners face an increasing challenge in minimizing the stress that heat and drought cause to plants.
Prolonged exposure to temperatures above 85°F (29°C) can severely impact plant health, resulting in wilting, leaf scorch, stunted growth, and even death. Recognizing and treating heat stress is essential to maintaining a thriving garden during the hottest months.
In particular, knowing how to water your garden in hot weather is important. This affects heat-tolerant lawns as well as ornamental plants.
Whether you’re trying to maintain a lush backyard, tend to potted plants on your porch or balcony, or protect your vegetables in hot weather, learning how to care for heat-tolerant plants is important for their survival.
Symptoms of heat stress in plants
As plants and flowers struggle to adjust to higher temperatures, they will develop symptoms that indicate they are suffering from heat stress. Regularly check your plants for these signs so you can take action:
- Withered Leaves and flowers can wilt from lack of water, even when the soil is moist.
- Curly leaves is a response to excessive heat and water loss.
- Burned leaf can be seen on leaves, leaves turn brown, dry at the edges or tips of leaves. This happens because the plant loses water faster than it can be rehydrated.
- Yellow leaves – especially at the bottom of the plant – indicates a lack of moisture.
- Fallen leaves is a stress response where the plant tries to minimize the amount of water lost through transpiration. This is especially common in trees.
- Flowers and buds fall will also occur early as heat stressed plants try to conserve energy.
- stunted growth can be common during periods of prolonged heat and drought.
- Sunburn can appear on leaves, flowers and fruits of the plant.
- Lack of fruit on vegetables is common, because heat-resistant crops will have difficulty growing.
- Blossom end rot also common in hot weather and most common in tomato, chilliAnd squash.
- Pests able to grow stronger when the plant is weak.
(Image source: Alamy)
How to care for plants in hot weather
Some plants, such as succulentare well equipped to handle heat by retaining water in their fleshy leaves. However, most plants do not have this ability and will be affected by heat.
Heat stress occurs when the rate at which a plant loses water through transpiration exceeds the ability of the soil to absorb water. This is exacerbated by inadequate watering and poor soil quality.
Implement these immediate and long-term care strategies to minimize heat stress. It may take time for your plant to recover, so continue with regular care and avoid major changes until your plant shows signs of improvement.
1. Water heavily – But only when the soil is dry
In general, when watering plants, water deeply and less frequently so that the plant can focus its energy on sending its roots to deeper soil depths. During periods of drought, the roots can access moisture reserves deeper in the soil.
If you water your plants too little, moisture will only penetrate the topsoil, leaving the plant’s root system shallow.
During heat waves, water in the top layer of soil evaporates rapidly, so heat-stressed plants also need deep watering.
How often you water your plants during a heat wave depends on the type of plant and whether it is in a pot or in the ground. Some plants will need watering once or even twice a day, while others will be fine for a few days.
Even in extremely hot weather, you can still overwater your plants. Instead of watering on a schedule, press your finger into the soil to check if the top two inches are dry. If the soil feels hard and compacted, it is likely very dry. If you are unsure, invest in a moisture meter.
(Image source: Getty Images)
2. Do not water in the middle of the day
Watering plants in the hot midday sun is hard work and not worth the reward. The water will quickly evaporate from the soil surface before the roots have a chance to absorb it.
The best time to water plants is early in the morning, which allows them to absorb moisture before temperatures peak.
If you miss the opportunity in the morning, you can water your plants in the evening, when the temperature has dropped. However, watering before dark will leave the plants wet overnight, increasing the risk of fungal diseases.
Minimise the risk by watering only the soil and avoiding wetting the leaves. This will reduce the spread of waterborne diseases and ensure the plant does not soak overnight.
3. Be more careful with containers
If possible, move potted plants to a shadier location during the heat of the day to protect them from the harshest rays. Also, use shadeespecially for vegetable plants, can be useful.
Potted plants will need daily Sprinklerseven twice a day at high temperatures. Soak the potting soil mixture thoroughly until water flows from the pot’s drainage holes.
Add water beads to the pot also help retain water. Since they will gradually absorb excess water, during dry periods the seeds will slowly release some of this water back into the soil.
Additionally, choosing a container with double walls helps insulate the plant roots from extreme heat or cold.
You can find double wall planters at Gardening Know How.
(Image source: Alamy)
4. Apply mulch around the tree
In addition to watering more frequently, mulch can help retain moisture and keep plants cooler. It does this by providing insulation against extreme temperatures and by creating a barrier that prevents excessive evaporation of moisture.
In addition to reducing watering, mulching has the added benefit of incorporating nutrients into the soil and helping to prevent weeds from competing with your plants for water.
Add another 2-3 inch layer natural coating such as compost, hay or wood chips around the base of the tree.
5. Remove dead leaves
While heavy pruning will put additional stress on the plant, it is also beneficial to prune away any severely damaged or burned leaves and dead flowers. This will reduce the plant’s energy expenditure on these parts.
Always use sharp scissors or hand pruners to minimize damage. Wipe the blades with a cloth soaked in disinfectant between cuts to avoid spreading disease.
6. No fertilization
Wait until your plants show signs of strong recovery to fertilize. Fertilizing encourages the plant to divert its energy to new growth when it needs repair. This will put too much stress on the plant and lead to poor growth.
Wait until the extreme heat has passed and the plant is showing signs of recovery before fertilizing again. However, if the plant has reached its peak for the year, it is best to hold off on fertilizing altogether.
Most perennials will do well if fertilized in early spring and again in summer when the new growth is established.
