“Avoiding the Perils of Soggy Soil”

It has been a cool moist spring. As of the end of May we had not experienced any temperatures over 90º this year. Last year we had 36 days of 90º temperatures by this time. Sounds ideal for plant growth, doesn’t it? Well, it generally has been great. One issue, however, has been plants killed by soggy soils. As the temperatures warm up this month our plants will still be suffering the consequences of the soggy soils and root damage.

Despite our reputation for drought, San Antonio is just as likely to have periods of excessive rain. A two week period with rain everyday is not unusual. This spring has been quite soggy. In a period when the soil does not dry out for several weeks we can expect root damage. The small feeder roots are actually drowned. The channels and air pockets are full of water instead of the oxygen that the roots need to function and survive.

This problem is exacerbated if the soil is cool like it has been this spring. Cool (or hot) soil limits root growth and so drown roots can not be replaced quickly. The net result is that you have a vulnerable plant. Its injured, reduced root system cannot pull enough water up to the foliage when, suddenly, we get hot weather. The plant wilts or dies.

If the lack of oxygen does not kill the plant that has an injured root system due to soggy soil, root rots often do. Root rots are diseases usually caused by fungus that feed on the roots. Soggy soil is an ideal environment for the development of root rots. The symptoms are the same as any root malfunction – a tendency to wilt, leaf burn in mirror image patterns, leaf yellowing and leaf drop. Where the plant dies from root rot is often loose in the ground at the end. All the anchoring roots have been consumed.

To minimize damage to plants from soggy soils here are some of the guidelines to follow:

• Use plants that are well adapted to our climate and soils. In South Texas they must survive wet periods as well as drought.
• Use raised beds for plants that are especially vulnerable to drainage issues. Descriptions of the plants in books, container labels and seed packet usually specify the drainage requirements.
• Only fertilize healthy growing plants unless you know the symptom is caused by a lack of nutrients. Wilting is not a symptom of the need for fertilizer.
• Do not add compost or organic material to a planting hole. Compost is a great addition when incorporated over a large area, but it can create a non-draining well that damages newly planted root systems.
• Plants that wilt in soggy soil are suffering from root damage caused by excess water. Do not add water.
• Follow the watering recommendations for landscape plants. Excessive water is more likely to kill an established well adapted plant than drought.
• Containers must have high quality, well drained potting soils and adequate drainage holes for plants to flourish.