Today's Paper News Sports Obits Events Classifieds Digital FAQ Newsletters Contact us

Ask a Master Gardener: What happens when we get too much rain?

by Peter Sutter | August 12, 2023 at 4:00 a.m.

What a summer we are having weather-wise.

Some of us were in a severe dry spell, others in the area were not so bad off. Now it is just the opposite and I am about to float away. A lot happens when you have so much rain in that short of a time. Here are some of the things that take place during a "soggy" spell.

Diseases: One of the problems heavy rain causes is that it creates a humid environment. It also splashes the soil on the foliage causing fungal and bacterial diseases to reach the leaves. Here are some wet weather diseases that may afflict the garden.

Powdery mildew: I haven't seen much powdery mildew this year because of the dry weather. Powdery mildew is a common disease caused by excessive rain. It looks like a white powdery growth on leaf surfaces and infects new and old foliage. Leaves generally drop prematurely. Wind carries powdery mildew spores and it can germinate even in the absence of moisture. Sunlight and heat will kill off powdery mildew fungus or an application of neem oil, sulfur, bicarbonates, organic fungicides with Bacillius subtillis or synthetic fungicides.

Fire blight: Fire blight is a bacterial disease that affects fruit trees, such as pear and apple.

Iron chlorosis: Iron chlorosis is a wet weather disease which prevents roots from taking in enough iron.

Lack of sunlight: The overcast conditions that occur during and after heavy rains will reduce the sunlight that reaches your plants. If you have many overcast days coupled with soggy soil, it can end up stunting the growth of the plant as it cannot create sufficient food.

Loss of soil nutrients: If you're growing plants in-ground in your garden, the heavy rains can wash away the soil. It will also leach out the nutrients and beneficial micro-organisms from the soil. The lack of nutrients will stunt the growth of your plants unless you reinvigorate the soil by adding organic compost and fertilizer. Nitrogen is one nutrient that is effected by the wet weather so it is important to replace it.

Pollinator reduction: When there are heavy rains, the pollinators like bees and other insects are unable to move freely among the plants. This means they won't be able to pollinate your plants. This can be a problem when your plants have reached the stages of flowering and growing fruit. A lack of pollinators can harm the potential growth of fruit on your plants.

Drowning roots: The most common problem of too much rain is the same as over watering. The water can soak up the soil and drown the roots due to a lack of air circulation and oxygen. This attracts bacteria that can cause root rot. This means roots will not be able to supply the required nutrients to the plant.

Injured roots: The heavy rains can also end up damaging the roots of your plants. The injured roots can attract pests and harmful bacteria that will damage or kill the plants. Some of the soil may wash away and expose the roots. Such roots can become an attractive food source for pests, fungal and bacterial diseases.

Cracked fruits: The heavy rains can end up providing too much water to plants too quickly. The fruiting plants that receive too much water can get the problem of cracked fruits. The plants that tend to have this issue due to over watering include tomatoes, radishes, melons, cabbage and squash.

A bright spot is the heavy rains can help avoid trouble in the future. Look for depressions where water stood for days and level it out with additional soil. Look where excess, unwanted water flowed and correct it by adding drain pipes or swales to redirect it to a more desirable area. Or consider adding a rain garden to capture and drain runoff instead of letting it wash away. These can be most attractive and environmentally-friendly. For areas with poor drainage, make note to build raised beds before planting there or plant only plants that can withstand periodic "wet feet."

Happy gardening!

Peter Sutter is a lifelong gardening enthusiast and a participant in the MU Extension's Callaway County Master Gardener Program. Gardening questions can be sent to [email protected].

Print Headline: Ask a Master Gardener: What happens when we get too much rain?


Sponsor Content