I’ve been gardening for more than 40 years. I’m particularly fond of vegetable gardening, although my wife is an avid gardener with flowers and decorative plants. Both of us, though, have confronted the challenge of various forms of fungus growing on leaves, and we’re both very hesitant about any chemical sprays. As a result, we’ve looked for and found organic and natural solutions.
There are more than 10,000 species of fungus in North America. Most present themselves as mushrooms, but a good many are mold. The fungus that affects plants is actually a form of mold. It appears as a white, powdery coating on leaves and quickly spreads. This is due to the way that a fungus reproduces: spores.
Spores are, essentially, microscopic seeds. They are about the size of a grain of pollen. Thus, a fungus can spread easily as the spores are carried on the wind. And that can be a real problem.
A fungus might first show up as a mold growth on cucumber leaves, but the spores will happily spread the fungus to other plants in the garden, and eventually to flowers and even trees in the yard.
One year I had a small orchard of apple trees annihilated by a fungus. By August the leaves had turned yellow and half of the leaves were on the ground. I didn’t lose any trees, but there were few apples and little growth that year.
Here are five natural ways to deal with fungus:
1. Trim affected leaves and plants.
Keep an eye on your yard and gardens, and the minute you see a leaf affected by what appears to be a fungus, cut the leaf at the base of the stem. If the entire plant seems affected, you may have to remove the entire plant.
Do not throw the affected leaves or vines in the compost heap. It’s nice to believe that the heat of a compost heap will effectively kill the fungus, but some spores will always find themselves on the top of the heap. The problem is that as you incorporate your compost into your garden or yard, you are spreading the spores. Either burn the leaves or place them in a plastic garbage bag and throw them out with the garbage.
2. Hydrogen peroxide.
Add one ounce of hydrogen peroxide to nine ounces of water, and pour the solution into a spray bottle. After removing any affected leaves, spray the surrounding plants and the affected plant with a liberal, misting spray of the solution. The hydrogen peroxide will kill and prevent further fungal growth. If you’re a bit squeamish about applying hydrogen peroxide to your fruits or vegetables, then you can use this approach on flowers and other decorative plants and use the next approach for your vegetable garden.
Keep an eye on the weather, however. After any rain, you likely should reapply the solution.
3. Acetic acid.
Sounds scary, doesn’t it? But in case you didn’t know, acetic acid is vinegar. Most store-bought vinegar has a 4 to 5 percent solution of acetic acid.
Vinegar is, in fact, a highly powerful, natural antiseptic. Combine the vinegar with an equal measure of water and put into a plastic spray bottle. Some people prefer the vinegar approach to hydrogen peroxide, but you can apply both to your plants if you want a little extra insurance.
I prefer this approach for vegetables and fruits. It’s easy to rinse off the vinegar before eating any fruit or vegetable. Reapply after a rain.
4. Baking soda.
Combine one quart of water with one teaspoon of baking soda. Add a half teaspoon of canola oil and a splash of dish soap and shake the bottle. Apply the same way as either the hydrogen peroxide treatment or the vinegar treatment.
One note: If you apply the vinegar solution to your leaves immediately followed by the baking soda solution, you may see some foaming. I’ve done this intentionally a couple of times to see if it was more effective, but there was nothing to indicate the combination was better than either one individually.
5. Change your garden location.
The simple fact is that a fungus doesn’t like bright sun. It prefers the cool shade of trees or other plants to grow and spread. Your garden location will be somewhat protected from fungus if it’s in full sun all day. My problem is that my current vegetable garden was started in bright sun and raised beds 30 years ago; since then, the surrounding trees partially shade it at times.
When to Go on High Alert
Certain weather factors encourage the rapid growth of fungus on plants. Humidity is a primary culprit. After any rain and especially a fog, be on the lookout for the sudden appearance of any fungus on your plants. It can take only a few days for the fungus to grow.
So, can you eat food with fungus? The answer is yes and no. Most fungus only affects the leaves of plants, not the fruits. If the tomatoes, cucumbers or squash look like they’re not affected, then just make sure to give them a good rinse in cold, running water. If they smell like mildew, toss them in the garbage.
Green, leafy vegetables are another story. A fungus causes a leaf to rapidly decompose. You’ll notice two things if you try to rinse some spinach, kale or lettuce that’s been affected by a fungus. For one, the leaves may dissolve in your hands as you rinse them. Worse, they may smell and taste like mildew. If a leafy vegetable is affected, toss it in the garbage.
Hopefully you won’t have a serious problem with fungus in your yard or garden this year, but if so, you now have the tools to battle it. Happy gardening!