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Johnson County

Research-based Information You Can Trust — Localized for your needs

Johnson County
11811 S. Sunset Drive
Suite 1500
Olathe, KS 66061

Office Hours:

Monday - Friday,
8:30 a.m. - 5 p.m.

(913) 715-7000
(913) 715-7005 fax

Map to our office

K-State Research and Extension is committed to making its services, activities and programs accessible to all participants. Reasonable accommodations for persons with disabilities may be requested by contacting Johnson County Extension at (913)715-7000. Notify staff of accommodation needs as early as possible.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service

K-State Research and Extension is an equal opportunity provider and employer.

Heat Waves and Humidity

Ask most people in the Midwest what their favorite time of year is, and their answer will seldom be August. Typically, it is hot. Very hot. And it’s humid.

What issues do heat and humidity cause? Outside of the standard environmental stresses of drought-stricken plants, sunburned fruit, steamed leaves, and crusted-over soil, the combination of heat and humidity create what can quickly become a breeding ground for pest and pathogen outbreaks. Both insects and fungi need warmth and moisture to thrive. When these two factors increase exponentially, combined with environmental stresses, disaster may be looming.

This is where your mechanical or physical maintenance practices can come into play and help you. While you may not be able to control the weather, you can still influence how the weather affects your garden.

Looking at your irrigation practices, you will want to be sure that when you water, you do not use overhead irrigation. Instead, apply water directly to the ground to be absorbed by the roots. This prevents water accumulation on the plant itself, decreasing the likelihood of disease development.

Mulching your gardens will benefit you by preventing splashing during watering –another factor that can lead to disease spread via fungal spores. Mulching keeps consistent soil moisture on your plants, with less frequent waterings, and it will even stop the soil from crusting over, which keeps oxygen flowing to your roots.

Even the simple practice of pruning and thinning your garden plants can benefit pest and disease prevention. By removing some of the plant matter, you are increasing airflow. This, in turn, decreases microclimate humidity and therefore reduces disease. Also, you are creating a less hospitable environment for insect pests, as they have fewer hiding spots from predators or the elements.

With less plant matter to support and keep alive, your plants can allocate more resources to the parts you retain. This will result in larger and healthier crops at the time of harvest.

The answer to most pest and disease control challenges in plants, even outside of times of extreme heat and humidity, is simply prevention. By maintaining healthy soil, rotating your crop growing locations, weeding, pruning, adding physical supports, and supplying proper light, water, and nutrients –you are encouraging the healthiest fruit and vegetable crops you can. Healthy, vigorous plants have the most success at fighting off those pesky insects and diseases. So, if pests do appear in your gardens during this most-inhospitable part of the growing season, the plants will be in their best shape to fend them off and ensure a productive harvest.

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Lawn and Garden Questions

Do you have lawn and garden questions? Please direct all gardening questions to our Garden Hotline, staffed by trained Extension Master Gardener volunteers and backed up by Extension staff who will assist you with your questions.


For more information, visit our page on composting.