Vegetable Gardening for Increasingly Hot Summers
Sharon A., Horticulture and Natural Resources Agent
“…temperature is projected to increase substantially in all seasons over the remainder of this century.
Heat waves will become more frequent, and summer overnight lows will become hotter.”
- Mid-America Regional Council Climate Risk & Vulnerability Assessment
While temperatures above 90°F might seem like a distant concern, now is the time to start planning for the summer heat. How you prepare your soil, what you plant, and how you care for your plants can make all the difference between a bountiful harvest and a garden that struggles to survive.
Prepping Your Garden Bed
Adding organic matter to your soil is one of the best ways to improve soil structure and moisture retention. If you’re establishing a new garden bed, consider whether an in-ground or raised bed is best for your needs. Raised beds are great for customizing your soil mix, giving you control over the amount of organic matter you incorporate. A mix of topsoil and organic matter in equal proportions is a good starting point. However, be aware that raised beds tend to dry out more quickly and require more frequent watering.
For any garden, it’s important to regularly incorporate organic matter—every 1 to 3 years is ideal. Depending on the source of your organic matter, it may add more than optimal amounts of phosphorus and nitrogen over time. Be sure to monitor organic matter and nutrient levels to ensure the best growing environment for your plants. For information on soil testing, visit our K-State Research and Extension Douglas County - Lawn and Garden webpage.
Consider installing drip irrigation to help maximize water efficiency. Drip irrigation delivers water directly to the base of the plants, reducing waste and ensuring that your plants receive the moisture they need. This system also helps minimize evaporation, which is especially important during the hot summer months. If you’re looking for more tips on irrigation, be sure to check out the recent K-State Garden Hour presentation on Maximizing Water Efficiency Through Drip Irrigation.
Choosing Heat-Resistant Vegetables
Some vegetables are more heat-tolerant than others. Vegetables such as Swiss chard, collards, sweet potatoes, southern peas (cowpeas), okra, kale, Japanese eggplant, tomatillos, yardlong beans (asparagus beans), and peppers are all excellent choices for summer gardens.
Spring-planted vegetables like spinach and lettuce tend to bolt (flower prematurely) and turn bitter as temperatures rise quickly. To extend the growing season for these crops, look for bolt-resistant varieties.
Summer Garden Maintenance
Shade cloth is a simple but effective way to protect your plants from extreme heat. Stretch shade cloth over low tunnel hoops to provide some cooling relief during the hottest part of the summer. Shade cloth can also extend the growing season for spring vegetables, or keep the soil cooler when seeding or transplanting fall crops in late summer.
Another essential tip for summer gardening is mulching your garden beds with straw or another organic material. Mulch helps regulate soil temperature, keeping it cooler and more consistent, while also conserving moisture in the soil.
Watering practices are key to maintaining plant health in the heat. Water your garden deeply and infrequently to encourage deep root growth. Shallow, daily watering leads to shallow roots, which are more susceptible to hot, dry conditions. Whenever possible, water earlier in the day to minimize evaporation and avoid overhead watering, which can promote fungal diseases.
Resources:
K-State Research and Extension Basic Principles of Water Management
University of MN Extension – Compost and soil organic matter: the more, the merrier?