Powdery mildew can survive through the winter even in cold temperatures. You might notice that it comes back year after year or always infects plants in a certain part of your garden. Indoor plants like African violets, begonias, ivy, jade, kalanchoe, and poinsettia commonly get powdery mildew. [2] X Trustworthy Source Missouri Botanical Garden Oldest botanical garden in the U. S. and center for botanical research and science education Go to source

Most fungi that cause powdery mildew grow during spring and fall since they don’t do well in temperatures over 90 °F (32 °C). Prevention tip: Allow your plants to dry out between waterings and check that indoor plant pots have good drainage. You should also avoid misting the plant or soaking the leaves.

Prevention tip: Leave the recommended amount of space between your fruits, vegetables, flowers, or plants. Read the plant container or seed pouch for the recommended amount of space. If plants have a lot of dense foliage that’s causing crowding, prune them back regularly.

If you’re dealing with powdery mildew on squash vines, it’s probably late in the growing season and the plant will have already produced squash. In this case, you don’t need to remove the leaves or treat for powdery mildew, since the squash aren’t affected. In general, you don’t need to cut off affected limbs from deciduous trees since the powdery mold doesn’t really damage them. [6] X Trustworthy Source Penn State Extension Educational organization dedicated to delivering science-based information to people, businesses, and communities Go to source

If your plants are drought-stressed or the temperature is above 90 °F (32 °C), wait to apply the horticultural oil since it can stress your plants too much. Horticultural oil treats the fungi on contact, so you may need to apply it again as the plant puts on new growth.

Choose an anti-bacterial mouthwash instead of a whitening or fluoride mouthwash.

It can also help to rotate the varieties you plant every year.

You don’t want to spray too often or baking soda will build up in your soil. This can strip calcium and magnesium from it.

Since milk leaves a cloudy or white film on the surface of the leaves, you may want to skip it for houseplants.