Plants need water to grow, but too much water can be as bad as too little, and in some cases, may lead to more problems. For the last few years, Brown County gardeners have been presented a unique set of challenges due to too much rain. While some rain is good to keep the garden watered, heavy rains almost every day can lead to some serious garden issues.

Much of the work of absorbing water and nutrients from the soil is done by root hairs — tiny hair-like, single-celled projections from the root surface. Excess soil moisture reduces the amount of air in the soil. This is a big problem because roots need air. While not big photosynthetic powerhouses like leaves, roots do breathe, and it is important to have oxygen present. Also when a plant receives too much rain or is overwatered, the large soil pores, fill with water, preventing roots from exchanging gases. Typically, the soil pores drain quickly, however, if there is nowhere for the water to go, the pores stay filled and roots start suffocating and dying. Of course, without roots, the plants start wilting. Sandy soils that drain quickly have fewer problems. Heavy clay soils, which are typical in an urban environment, have fewer soil pores, and retain more moisture, leading to more plant death. Two things you can do is mulch to keep plants from drying out when there is no rain, and avoiding too much nitrogen.

You should be on the lookout for is disease. When there is a lot of rain, conditions are ripe for the spread of diseases, especially fungal and bacterial diseases. The rain will splash the disease up from debris in the garden or from plant to plant, and the fungus will begin growing on the plant. Frequent rain and high humidity can also lead to blight spread.

Powdery mildew is also a concern, especially on cucurbit plants such as cucumbers and squash. You can identify it just from the name — you’ll see powdery white patches on leaves. These will eventually turn yellow and brown and potentially damage or kill the leaves. Downy mildew is another white fungus that appears on leaves and plant parts. It looks like cottony fuzz up close. Both of these can affect many plants in the vegetable garden and landscape, so you should be on the lookout.

Another rain-soaked problem in the garden is nutrient deficiency. With the root hairs dying the plant’s ability to take up calcium and other nutrients is limited. This problem arises about midsummer. Plants in the vegetable garden grow fast and require soil nutrition to keep healthy. The growth of the leafy, green part of the plant depends heavily on nitrogen. When the plant has a nitrogen deficiency, it starts mobilizing the nitrogen from older leaves to feed the new ones, basically killing off the old to feed the new. However, excess nitrogen can make plants sink so much energy into growing leaves and stems that they don’t have enough energy to bloom or set fruit. You have to find the right balance. The University of Minnesota suggests you use a moderate amount of nitrogen fertilizer early in the season, before plants bloom (this goes for both vegetables and flowers), then side-dress with a little bit of high-nitrogen fertilizer (such as urea or blood meal) after blooming has started.

Another nutrient problem with all the wet weather we have been having is – calcium. A common issue with tomatoes, and several other fruits including peppers and squash, is blossom end rot. Calcium is an important part of the cell wall structure in plants. When that breaks down due to a lack of calcium in the fruit, tissues can be damaged and result in the black damage we see on the end of the fruit. This deficiency of calcium can come from a few problems, including lack of calcium in the soil, too much nitrogen fertilizer (makes the plant grow faster than the calcium uptake can supply), too little water (calcium is brought into the roots with water), or damage to the roots caused by excess moisture.