Wednesday, July 18, 2012

Wilting in the Rain...

It’s hard to believe how much rain we’ve received over the past few days. Especially when compared to this time last year. The ground is soaked and in landscape areas with poor drainage, prolonged saturation can often lead to a variety of plant problems. One of the more common symptoms of these problems is wilting in the rain…

Excessive soil moisture...
(like all the rain we’ve received) flushes oxygen from the soil. Plant roots need O2 to take up water and nutrients. In the absence of sufficient O2 plants often wilt – despite the presence of soil moisture. One of the prime reasons gardeners use raised beds is to help remove excessive moisture from the root zone. Also, amending soils with various types of organic matter can help provide an optimum balance of aeration, drainage and water holding characteristics. Raised beds and amended soils are the most effective means of dealing with the “monsoonal rains” we often receive.

Soil-borne diseases...
can become another major problem during periods of prolonged saturation. Fungal pathogens like pythium, phytopthora, fusarium, rhizoctonia and thalaveopsis (all bad guys) thrive and reproduce best under waterlogged conditions. Fungi need a water film to spread and O2 stressed plants are more susceptible to diseases – creating a “perfect storm” of environmental conditions (forgive the pun). Plants infested with a root disease often have a wilted appearance even though there seems to be plenty of water in the soil or pot. 

Of course the response of most gardeners to a wilted plant is to apply water. However, under these conditions, watering may only make matters worse. Monitor conditions closely and don’t over-water plants that seem to be wilting in the rain…

1 comment:

David said...

I'm having to bring in my potted agaves each afternoon and running a fan on the very wet ones. Some can take it, but some are the 'keep me dry or else' types.
Nice we don't have drought to worry about.
David