As the summer sun blazes and temperatures soar, organic gardeners like us are faced with the challenge of nurturing our precious plants through the scorching heat. Intense summer heat can cause issues for even the most heat tolerant plants in our garden and these issues will be compounded even further by drought conditions.
Here are some of the key strategies you can use in your garden to combat heat stress and drought:
Choosing the right plants
Growing plants that can naturally handle high heat will make your life easier than trying to force things to grow in unfavorable conditions. These plants have evolved to withstand high temperatures and are more likely to flourish in the summer heat:
- Herbs like basil, rosemary, thyme, oregano, sage, tulsi and lemongrass
- Vegetables like tomatoes, peppers, okra, cucumber, eggplant, amaranth, beans, summer squash, melons and corn.
- Flowers like zinnia, marigold, celosia, black eyed susan, sunflowers and lantana
- Sweet potatoes
- Passion vine
- Cacti and succulents like dragon fruit and aloe
- Summer cover crops like sorghum sudan and cowpeas.
Increasing soil organic matter
For every 1% increase in soil organic matter content, the soil's water-holding capacity can increase by up to 25,000 gallons of water per acre of soil. Even a small increase in soil organic matter can have a significant impact on the soil's ability to retain moisture. How to increase soil organic matter:
- Add compost to your beds to top them off regularly.
- Use organic mulches that break down like straw, leaves and wood chips.
- Grow cover crops.
- Avoid chemicals as they can harm beneficial microorganisms that contribute to organic matter decomposition.
- Adopt organic gardening practices that promote a healthy soil ecosystem.
- Use organic amendments like pelleted organic fertilizer, worm castings and biochar.
Proper soil moisture is essential to combating heat stress. With increased heat comes increased transpiration, which rapidly sucks moisture out of the soil.
- When you water, water deeply and thoroughly to ensure the moisture reaches the roots and wets the entire soil profile.
- Drip irrigation or soaker hoses are excellent methods as they deliver water directly to the soil, minimizing evaporation.
- Watering in the evening should be avoided, as it can lead to prolonged moisture on the leaves, increasing the risk of diseases.
- You should expect your plants to need at least 1.5-2 inches of irrigation per week during intense heat and dryness.
- DO NOT let your soil dry out as it will go hydrophobic and be very difficult to rewet.
- We are hand watering the Vego Garden at Texas Eco Farms by hand daily.
Mulch, mulch, mulch... Did I mention mulch?
Mulching is a gardener's best friend, especially during the summer months. It’s a cheap and easy sun shield for the soil that has a number of other benefits.
- Apply a thick layer of organic mulch around your plants to help retain moisture, regulate soil temperature, and suppress weed growth.
- Mulching will keep the soil cooler, reduce evaporation, and minimize stress on your plants' roots.
- The effect of mulch on soil temperature is dramatic. On a scorching summer day, the soil in non-mulched areas can reach temperatures up to 140°F (60°C), while in mulched areas, the temperature can remain a cooler and more plant-friendly 90°F (32°C).
In addition to mulch shielding the soil from direct sun, you can use shade to shield your plants from the sun.
- You can use 30% - 50% shade cloth to provide drastic relief for your plants.
- An alternative to shade cloth is a lath structure, where thin strips of wood or bamboo are spaced evenly above a garden bed.
- Group taller plants or sun-loving plants in a way that provides shade for more delicate or shade-tolerant plants. The taller plants provide shade. E.g. planting sunflowers on the west end of a garden bed will help shade the bed from the intense late day sun.
- Set up temporary shade structures, such as shade sails or pop-up canopies, during periods of intense heat. These can be moved as needed to protect different areas of your garden. We’ve even used cardboard for this purpose.
I hope these strategies help your summer gardens thrive!