Too much water drowns plant health

My three-year-old son stood looking out the window singing to himself: “Rain, rain go away, I want to come out and play, rain, rain go away.” I chuckled to myself and thought, “If he only knew how fitting that song was.”

With water being one of the most important ingredients of life, we are taught at any early age that plants need water to survive. However, many gardeners do not realize that overwatering is more deadly than underwatering a plant. Here is what you need to know about the recent rains and what you can do to keep your flowers and vegetables healthy and growing:

Light, water and air are the three main inputs needed for plant growth and development. Light is used to manufacture sugar to feed all the living cells in the plant. Air is used both above ground and below – but for two different reasons. Green plant tops pull carbon dioxide from the atmosphere during photosynthesis to create sugary food for the plant. Conversely, plant roots use the oxygen in the air in much the same way we breath for respiration.

Water is needed for a variety of reasons, including sugar production and nutrient uptake and movement in the plant. It is this air-water relationship in the soil that is being most affected by the recent rains.

Soil is formed from tiny pieces of disintegrated rock. From largest to smallest, these particles are sand, silt and clay. The next component is organic matter. It is the result of the decomposition of once-living plants and animals. The final, and most important portion of soil, is pore space. Pore spaces are areas in the soil not occupied by any of the above materials. They are filled with either air or water. Ideally, plants prefer to have a 50-50 mix of the two.

However, too much of either is not good. If there is more air than water, plants begin to wilt from lack of moisture. The drier the soil gets, the more likely the plant is to die. If there is more water than air, plant roots begin to drown and shut down from lack of oxygen. The wetter the soil gets for an extended period of time, the more likely the roots are to die. Often, overwatering and under watering look the same: Leaves that wilt and droop eventually turn yellow to brown and die.

So what can be done for an overwatered plant? The answer is not much. Because overwatering is a physical condition, the first step is to change the conditions. Allowing the soil to dry out as quickly as possible may help the plant recover. Short term, pull the mulch back from the stem and roots for a short time until the soil dries. Likewise, turn off the automatic irrigation system for several days to allow soil moisture to decrease. Long term, add organic matter to slowly raise the bed or planting area to help keep water from entering the bed from adjacent ground. Relocate flood-prone beds and gardens to higher ground that is not likely to flood or encounter water runoff. Finally, install some sort of French drain system that allows the water to be moved out of the area to lower ground after a heavy rain fall.

As a final thought, nitrogen is key for green growth and development. However, nitrogen is highly water soluble. Because of the excess rains, plants may benefit from a light application of a high-nitrogen, low-phosphorus, low-potassium fertilizer. Something like a 33-3-3 lawn fertilizer with no added chemicals, or nitrate of soda, which is 16-0-0. Use them sparingly and hope for drier weather.