Grape vines are both decorative and useful additions to the garden. They provide a way to green up fences and walls that would otherwise look dreary. They can pour over archways or patio covers adding a Mediterranean design to the landscape. They also offer tasty fruits that are good for you and handy to eat since they come in bite-sized packages. For people who love their wines, there are many different wine grapes to feed the hobby of wine making.
There are also so many different varieties of grapes that most areas of the country can find a good selection to match almost any climate. But one thing that can take the fun out of growing grapes is discovering that your rich, green leaves or swelling fruit is covered with a white or gray powdery blush. This is mold or mildew, a fungus that grows on grapevines. It will not hurt you to eat grapes with mildew, but the fruit isn’t very pretty and the flavor can be affected. Severe attacks of mold can damage the health of vines.
Although you can spray your vines with fungicides, there are two better, organic ways to stop mildew or mold on grape plants.
The easiest way to avoid the problem is to plant American varieties. It is the European grapes that are most prone to developing mildew problems. Even in hot, dry areas, mold can still be a problem. If you can find varieties that will suit your taste, opt for naturally resistant plants like most of the American grapes.
The second way to stop fungus problems is something I learned while in England many years ago. Sulphur dust is a low cost treatment that is perfectly safe to use. It can be applied as a dry powder or mixed with water and sprayed. Do not apply it when temperatures rise over eighty five degrees Fahrenheit. And make sure you wear gloves, eye protection and even a mask. The dust is an irritant. My eyes burnt badly for a whole day when I decided to just add a little more to one missed spot and didn’t bother putting on glasses. Don’t do it!
Sulphur dust is best applied right after flowering as the tiny fruits begin to swell. Cover leaves and fruits lightly. Sulphur is said to be a good way to combat mites and other garden insect pests, too. It does stop mold and mildew on grapes. And it is organic.