3-step plan for limiting fungal diseases in next year’s garden
Question: We had a terrible issue with different plant diseases in this year’s garden. So many of our perennials and vegetables developed spots or mold on the leaves. I know it was a really wet spring and that makes this sort of thing worse, but is there anything we can do now to reduce our chance of diseases next year?
Answer: Plant pathogens appear from time to time in every garden, even when the gardener puts in his or her best effort to keep them in check. However, there are some steps you can take to help reduce your chances of developing many of the more common fungal diseases.
Some pathogens, such as powdery mildew, leaf spot and early blight, are more common than others. And some are more destructive than others, too. While there are certainly pathogens that can kill plants, there are many others that only damage the plant aesthetically but do not impact the overall long-term health of the plant. In my own garden, I don’t worry too much about diseases whose impact is only on the aesthetics of the plant. Instead, I focus my attention on the pathogens that are more destructive.
Plant pathogens that live in the soil (soil-borne) can be very persistent and difficult to control, but they’re very predictable. If you have them one year, you’ll probably have them in subsequent years, too. Pathogens that spread via wind, water and insects are often more unpredictable and problematic since we don’t know they’re coming.
It’s important to recognize that, when it comes to almost any disease organism, a little prevention goes a long, long way.
Your first line of defense against these issues for next season is this simple three step plan:
Plant only resistant varieties. This all-important step essentially designs the pathogen out of the system. By choosing vegetable, herb, fruit and flower varieties with natural resistance to pathogens, you’re reducing your chances of ever facing the disease to begin with. For example, if you’ve battled powdery mildew on your bee balm plants in the past, only plant selections of bee balm with noted powdery mildew resistance in the future. For nearly all pathogens, there are varieties of plants bred to be resistant to that particular disease organism. When you purchase seeds or plants from a local nursery or catalog, any disease resistance should be noted on the packet or tag. Seed catalogs often have a “key” to help you determine which veggie varieties are resistant to which pathogens. Do your homework and pay attention to this information. It can save you a lot of trouble down the line.
Maximize air circulation. Many disease organisms are fungal. Fungal spores thrive in wet conditions. They reproduce more rapidly and are more problematic on plant foliage that’s wet or during periods of high humidity. By spacing plants properly, and thereby increasing air movement around them, fungal issues can be slowed or stifled. Give your plants plenty of room; don’t over-stuff your garden.
Employ good cultural practices. Cultural practices are all of the things you do in your garden. From pruning and fertilizing to watering and harvesting, cultural practices play a huge role in promoting — or discouraging — diseases of all sorts.
For example: Water plants during the morning, whenever possible, to allow enough time for the foliage to completely dry before nightfall.
Clean your pruning shears after working on diseased plants. A simple application of a spray disinfectant or a quick dip in a 10% bleach solution is enough to kill most plant pathogens on pruning equipment.
Don’t over-fertilize plants. Succulent, tender foliage is more susceptible to certain fungal attacks.
Avoid working with wet foliage. Fungal spores spread easily from plant to plant on water droplets clinging to your skin or clothes.
Regularly inspect plants for signs of disease. Remove infected foliage and discard it in the trash or bury it to prevent further spread.
Beyond this three-step plan, there’s little you need to do to prevent diseases in next year’s garden. If we have another wet spring, fungal issues will undoubtedly crop up. Don’t panic about them; most do not spell certain death for plants.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to [email protected] or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.