Drought and heat are inevitable challenges in the vegetable garden. In the Southeastern United States, rainfall can seem like it's feast or famine -; there's either too much or not enough. Unpredictable rainfall combined with periods of extreme heat makes summer the most stressful season (for plants and humans) in the garden. Wet summers lead to a variety of plant diseases and out-of-control weeds, while droughts result in stunted, wilted crops that produce little if they even survive.
Cory Tanner, director of the Clemson Extension Horticulture Program Team, shared the below tips to help your vegetable garden thrive during the sweltering summer months:
- Most vegetable plants require the equivalent of one inch of rainfall per week to grow normally. That requirement increases when temperatures exceed 90 degrees Fahrenheit.
- Don't wait until your plants are showing stress. By the time they wilt some damage and lost yield has already occurred. Avoid drought stress from appearing by irrigating your crops before the soil becomes extremely dry. Depending on the soil type and condition, dry soil can sometimes be extremely difficult to rehydrate.
- Use organic mulch (shredded leaves, straw, hardwood mulch, etc.) to reduce water evaporation from the soil and insulate the soil and plant roots from extreme heat.
- Consider temporary shading to give plants relief during periods of extreme heat. Most vegetables prefer full sun for best production so shade should only be used temporarily during the hottest weather. Floating row covers suspended above a crop are a practical way to provide temporary shade in the garden. Container gardens can be moved into shady sites temporarily.
- Fruiting crops, like tomatoes, do best when provided even soil moisture. Avoid big swings between wet and dry soil, by irrigating frequently and deeply during dry periods. Not only will this reduce drought stress, it will also reduce common problems in tomatoes like blossom-end rot and fruit cracking.
- Utilize drip irrigation which applies water directly to the soil, keeping it out of the air and off of the foliage. Drip irrigation is 90-95 percent more efficient than sprinkler irrigation. It also applies water more slowly which allows more of it to soak into the soil and wet a deeper soil profile.
- Make sure you water deeply. Shallow irrigation can be more harmful than no irrigation at all. Make sure when you irrigate that the moisture is reaching a soil depth of at least six to eight inches. Otherwise, plant roots will concentrate near the soil surface making them more vulnerable to drought and heat stresses. Watering deeply encourages deeper rooting and more resilient plants. Check your system by digging into the soil profile periodically after an irrigation cycle to see how deeply the soil is wetted. If water is not reaching the recommended depth, then you'll need to increase your irrigation time or the number of irrigation cycles you run, or both, depending on your soil type and irrigation system.
Want more gardening tips? Let us know and we can connect you with Cory Tanner for expert advice.