Rainy days mean lush gardens, but beware moisture-loving fungal, bacterial diseases
With the peak of summer heat upon us, it may seem even more of a blessing than usual when the errant rain shower finds its way to our gardens. After all, it’s hot, the plants need to be watered, and Mother Nature has just saved you a few bucks on the next water bill.
However, looking a little deeper, gardeners may also need to take these errant showers as a precursor of what could come and take proactive steps to prepare against potential adverse effects. Heat and moisture are the two ingredients needed for many plant fungal and bacterial diseases to thrive.
Rain showers find their way to gardens mid-day or even in the evening, allowing plants to become infected and sick when foliage exposure to moisture is prolonged for long periods. There are, however, steps that can be taken to lessen this risk.
Looking first to the obvious: Outright exclusion of a plant from a garden upon diagnosis will help isolate a problem, preventing it from becoming an all-out issue. This practice should primarily be considered with smaller annuals and perennials. If an infected plant is not of sentimental or monetary value and does not take away from a landscape, getting it out of the garden before it could make anything else sick is a solution.
While this practice is typically observed with virus-infected florae (because viruses have no treatment), the concept can be applied to fungi and bacteria. The infirmed plant and any remnants should be fully disposed of and removed from the garden area to prevent recontamination.
Mulching, a well-known practice among gardeners for maintaining plant health, is also significant in disease prevention. By regulating soil moisture and temperature and acting as a weed barrier, mulch helps to prevent the spread of fungal spores and bacteria, making it an ideal tool for disease mitigation.
Other general maintenance practices, such as pruning, tying and staking, are not just about aesthetics. These efforts increase airflow within a plant stand, ultimately reducing the relative humidity within a microclimate. Remember, humidity equals moisture. Moisture equals disease. Reduce the humidity and you reduce the disease.
If fertilizing, know that too much can make plant diseases more likely to thrive. As a result of fertilizing, your plant will grow lusher. Ultimately, this will decrease airflow and increase humidity, instigating disease formation. The new growth will also be more tender, making it prime ground for pathogens to infect.
When managing moisture in the garden, it’s essential to be both thankful for the rain and prepared to address the issues it can bring. By following good gardening practices and thinking ahead, you can ensure that your plants continue to thrive, even in the face of potential disease.
Anthony Reardon is a horticulture agent with Kansas State University Research and Extension. Need help? Contact the Johnson County Extension gardening hotline at 913-715-7050 or email garden.help@jocogov.org.
