Is it hot enough for you yet? The last week of July was brutal! I could not step outside without breaking into a sweat. As I look out of my home upon my landscape I marvel at the ability of plants to withstand sustained temperatures above 90 degrees for days on end.
When temperatures reach 90°F and above for extended periods plants begin showing signs of stress. Plants have optimal temperatures at which they grow best. Increased soil temperatures along with extreme air temperatures can slow plant growth.
Many plants show signs of stress when temperatures are extreme. Among these signs are wilting, curling, or burned foliage. Low moisture in the plant creates a lack of water pressure within the plant structure. This in turn leads to wilting. Many plants will recover when temperatures cool. A plant is experiencing heat stress when it wilts during the hottest part of the day and then recovers in the evening or morning hours.
During times of extreme heat, questions about blossom drop start to pour in. The questions usually center on tomatoes, peppers, squash, and cucumbers. Prolonged exposure to high temperatures will cause some plants to abort (or “drop”) their flowers and buds. This indicates that the plant is going into survival mode. When temperatures cool, most plants will return to normal production.
Watering is crucial to reducing heat stress in the garden. Deeply watering the plants is ideal. Plants that have a tap root system draw water from deeper into the soil. Shallow-rooted plants tend to dry out more rapidly which leads to faster wilt. Younger plants need more water than established plants. It is often said that watering is best done in the morning however anytime your plants are exhibiting signs of wilting they should be watered. This will minimize the time that the plant spends in a wilted state. Do not forget about container plants! They require daily watering during periods of extreme heat. A layer or two of mulch will aid tremendously in conserving soil moisture and regulating soil temperature.
Do not forget to take care of yourself in the garden. Stay hydrated, wear a hat, work early in the day if possible, and always wear sunscreen! Please contact me if you have any questions. Stay cool!