Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, June 16, 2007
“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
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
• 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.