Understanding Heat Stress in Plants
Is it too hot?
The impact of heat varies depending on the type of plant. Cool-season plants such as pansies, snapdragons, and vegetables like broccoli and lettuce struggle when temperatures rise above 75°F. In such conditions, these plants often bolt, meaning they go to flower and seed prematurely. On the other hand, warm-season plants, including tomatoes, peppers, squashes, zinnias, impatiens, and annual vinca, thrive in temperatures ranging from 75°F to 90°F. However, even these heat-loving plants can suffer when temperatures climb into the mid to upper 90s or reach 100°F. New perennials, trees, and shrubs are also vulnerable to extreme heat, although mature plants tend to withstand high temperatures better.
Watering During Hot Weather
Should you water more when it’s hot?
Not necessarily. While plants might appear wilted in the afternoon heat, they often recover in the cooler evening temperatures. If your plants look revived in the morning, they likely do not need additional water. However, if they remain wilted in the morning, they need watering. Overwatering can occur if you don’t check soil moisture levels before watering. During extreme heat, plants may temporarily shut down their functions, which could lead to overwatering if you’re not careful.
Solution:
- Get a water meter: This tool helps you accurately measure soil moisture levels, preventing overwatering.
- Water deeply: Consistently water your plants deeply, not just during heat spells. This encourages roots to grow deeper, making plants more resilient to heat and stress. The top few inches of soil dry out faster than deeper layers, so deep watering ensures roots access more stable moisture levels. This practice benefits all plant categories, including annuals, perennials, shrubs, trees, and vegetables.
Maintaining Plant Resilience
Remember, plants are quite resilient. Like people, they withstand stress better when they are healthy. Keeping your plants well-maintained and healthy helps them endure the heat and other environmental challenges more effectively. Ensure they have proper nutrition, adequate water, and are free from pests to enhance their resilience during heat waves.
