The heat of summer can be a death sentence for your plants, but over watering can as well. The best thing you can do is keep the soil moist by watering when the top 1 inch (tip of your finger) feels dry to the touch and to be aware of the symptoms listed above.
Avoid watering when temperatures are below 40°F or when sustained freezing temperatures are expected within 24 hours as this water will freeze and not be available to the plants.
Watering plants in 100-degree heat must be done daily, especially if the soil has no ground cover.
The good news is that most plants will bounce back between 7-14 days if they're given proper care (which includes rehydration). If this isn't possible because major damage was done or little healthy root system exists then expect about 2 weeks until improvement can be seen.
During spring and summer in Southern California, she suggests drip watering three times a week for 18 minutes, then adjusting from there if the soil is too wet or dry. Don't know how to tell? Stick your finger in the soil. If it's consistently moist 2 inches down, your plants are fine.
The heat of summer can be a death sentence for your plants, but over watering can as well. The best thing you can do is keep the soil moist by watering when the top 1 inch (tip of your finger) feels dry to the touch and to be aware of the symptoms listed above.
The general answer is around 90 degrees F, with some exceptions to the rule. This means that when temps rise above 90 and remain there for a lengthy spell: Leaves wilt. Water evaporates into the atmosphere more quickly in high heat, draining a plant's reserves.
Plants in containers and hanging baskets may need water twice a day - especially when weather is windy and hot, containers dry out very quickly. Check often, as most will need water at least once a day, and some may need water in the morning and the evening.
Most summers can be warm, but abnormally high temperatures can stress plants, resulting in sunburn, wilting, and even death. Plants in containers are more vulnerable to extreme heat and weather because the air temperatures can “fry” the roots and tops of plants.
Containers need frequent watering.
Because there is little soil in a pot to hold water, container plants need to be watered more frequently than plants in the ground. In hot weather, they may need to be watered daily.
The best way to tell if your plants need water is to stick your finger about an inch into the potting mix—if it feels dry, break out the watering can. If you detect dampness, check back again in a day or two. For smaller houseplants, you can also pick up the whole container. If it feels light for its size, add water.
Most plants shut down during extreme heat, so if it is over 100 degrees, it may be best to wait to water even if your plant is stressed. Throw a damp sheet over it, or mist it lightly to bring the temperature down. Mist leaves with a spray nozzle to cool down plant and reduce transpiration.
Some signs of heat related stress on plants include: leaf scorch, leaf rolling, wilting, blossom/fruit drop, sunscald, blossom end rot, and other variable conditions that could be brought on by secondary pathogens. Heat stress adversely affects plant metabolism, disrupting their vital biochemical processes.
“You want to keep them from getting stressed in the first place.” If you do spot plants drooping or wilting, water them right away. Mulch. A layer of mulch over the roots of your plants helps in two ways: It insulates the soil against extremes of temperature, and it prevents moisture from evaporating.
The general rule of thumb is that most plants freeze when temperatures remain at 28°F for five hours. Of course, there are exceptions to this rule. Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds.
It can take anywhere from a couple of days to a couple of months for stressed plants to recover. Recovery time depends on the amount of damage that the heat caused to the plant. If a stressed plant is completely neglected during a heatwave, it can take several months or even be impossible to revive it.
Don't Water at Mid-Day in the Sun. "Don't Water Your Plants in the Middle of the Day!" How many times have you heard that? "Only water your plants in the early mornings or late evenings." THE CHALLENGE: That's easy to say, but not always easy to do.
Mornings and evenings are excellent times to water gardens when using a drip irrigation system or soaker hose. Watering in the evening isn't a problem as these methods don't wet plant foliage.
Avoid applying fertilizers when plants are dormant or under heat and drought stress. Fertilizers should be incorporated into the soil to prevent losses. If you cannot physically incorporate a fertilizer at this point in the season, it may be best to stick with a water-soluble fertilizer.
During extremely hot weather (daytime temperatures above 90F and nighttime temperatures above 70F), try to water daily or every other day. In a 10x10-foot garden, this would mean giving your plants 8 to 9 gallons of water each day.
Each plant has its specific needs, but as a starting point plants in pots with: 3-4 inch diameter containers need about half a cup of water. 5-7 inch diameter containers need about 1 cup of water. 8-10 inch diameter containers need about 2-3 cups of water.
Morning watering is actually preferable to evening watering as the plant has time to dry before the sun goes down. At night, water tends to rest in the soil, around the roots, and on the foliage, which encourages rot, fungal growth, and insects.