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Gray Mold

What is gray mold? It is a fungus that can affect any part of the plant and is one of the most common diseases found among bedding plants. This disease will easily infect plants that are already damaged or beginning to die. Moisture is one of the main causes of gray mold. The wetter your plants are, the more susceptible they are to becoming infected.

How to Identify Gray Mold

  • The symptoms of gray mold depend on the type of plant and environmental conditions, but generally spots that appear water-soaked will form on the leaves.
  • These spots will then change color from gray to brown, eventually covering most of the leaf and causing it to wilt.
  • Under really humid conditions, grayish webbing may appear on the leaves. In this webbing are structures that contain spores.
  • Petals, stems, and buds can also be infected.
  • Eventually, all of the infected parts of the plant will be covered by a fuzzy gray growth.

How to Control Gray Mold

  • Remove the infected plants and destroy them.
  • Clean thoroughly between your plants so that the disease cannot infect your other plants.
  • You can try using foliar sprays with cultural controls on your plants to prevent further infections.


  • Handle your plants carefully when transplanting and pruning. Gray mold usually attacks wounded plants, so avoid harming your plants.
  • Keep your plants dry. Avoid overhead watering and watering late in the day. Give your plants time to dry off after watering them during the day.
  • Space your plants properly to encourage good air circulation.
  • Remember to clean between your plants. Remove any debris, including cuttings and dead leaves.


I bought a spider plant all

By ruthe Fitzsimmons on March 9

I bought a spider plant all of the leaves are yellow and the tips are black and appear to be bent like an edge.
Could you please help?

It sounds like your plant may

By Almanac Staff on March 10

It sounds like your plant may be getting too much sun. Move it to a cooler spot in the house; be sure it is not close to heat vents or on top of the television.

I have peonies that seem to

By Twiggs1221

I have peonies that seem to have this gray mold on the leaves. It hasn't turned brown or wilted the leaves, but I've noticed that my hydrangea that is next to it doesn't look too good. I have 3 others in my gardens and they all look great still. Could whatever is on the peonies have affected my hydrangea too? Its not as green and lush as it should be and the edges of the leaves look like their browning. I live in zone 7 and my peonies are well passed bloomed. I usually wait til fall to cut the foliage down. Should I have cut that down sooner? And do you think I should move the peony because it is rather close to the hydrangea? When I put the hydrangea there it wasn't as big as it is now.

It's probably powdery mildew

By Almanac Staff

It's probably powdery mildew from humid conditions. It isn't pretty but it won't hurt the peony this late in the year. Cut it back in the fall and dispose of the leaves. Make sure your peony has good air circulation next year. It may be a good idea to move it away from the hydrangea. Go to our peony page for more information.


I have a question about my

By Sande Sanders

I have a question about my garden and I think it is probably related to this article about gray mold. I recently moved to a northern California coastal town. Long growing season, very temperate climate. I'm living in my RV and am surrounded by asphalt, so I container garden, allot. I'm trying to keep the pots wet enough so that the plants don't wilt from the heat, but its humid here.
My sage plants turn yellow and get brown spots. My squash gets spots, turn brown and die. The gray webbing takes over. yuck,but the plant keeps trying. I have tomatoes near the squash, one looks like it rotted from too much water, but I don't water until the top few inches are dry. That's every other day here.
Any suggestions? I thought the plants were getting sunburned, maybe that's the damaged entry point for the gray mold. Some one suggested shade cloth. But doesn't that seem weird with tomatoes?

Vegetables and herbs can

By Almanac Staff

Vegetables and herbs can suffer from various problems due to high humidity, high heat, too much/too little water, etc. Too much water can cause sage leaves to yellow and form brown spots, but so can high temperatuers, etc. Sometimes squash gets downy mildew, powdery mildew, or white mold. Tomatoes can also get white mold, powdery mildew, root rot, etc. For some disease information, see:

In general, make sure not to waterlog the soil, and check the drainage at the bottom of the containers--be sure the drainage hole(s) are not blocked. Temperatures might get very hot if your containers are on asphalt, so a shade cloth during hot afternoons might be helpful, or positioning them to get partial shade in the afternoon. You can also add a little mulch on the soil surface--but keep the mulch from directly contacting the main stem of the plant, in case the humid air might encourage disease. Avoid overhead watering, which can encourage disease--water the plants at the base, or use self-watering containers.

If you could set up a fan to blow gently on the plants for a few hours each day, that might help to avoid diseases in humid weather. The more (gentle) air circulation, the better.

Some of my gladiola's florets

By jamil

Some of my gladiola's florets did not open/ bloom on the top found them empty from indside. Is it a disece or under fed? Thanx.

It sounds like your gladiolus

By Almanac Staff

It sounds like your gladiolus may have had thrips. They feed on the shoots and flowers.

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