Correcting Hydrophobic soils - Ask Extension
My husband used a potting mix from bags for our raised bed. It will not absorb water; it looks wet but is totally dry 1/8" under the top layer. I've ...
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Correcting Hydrophobic soils #145504
Asked August 06, 2013, 2:33 AM EDT
My husband used a potting mix from bags for our raised bed. It will not absorb water; it looks wet but is totally dry 1/8" under the top layer. I've read Extension publications including, Using Wetting Agents (Nonionic Surfactants) on Soil from N Carolina. Years ago an Extension Specialist told me for a potted plant with this problem to use a small amount of soap or detergent and really squeeze the mix to change the surfactant aspect (water absorption) of the mix. BUT this is a lot of mix.
I tested a mixture of 1/2 my clay soil and1/2 the potting mix; it seems
better but if it dries out might it again be an issue, as indicated in
the publication?
Where and what Wetting Agent is available for use in a raised bed? Or should I remove all and start over with a garden compost mix?
Thank you!
Where and what Wetting Agent is available for use in a raised bed? Or should I remove all and start over with a garden compost mix?
Thank you!
Multnomah County Oregon
Expert Response
The trick with potting soil is to use hot, even boiling water to do the initial wetting. It is not the best mix for a standard raised bed unless it is pretty small. Also, not all potting mixes are created equal. The more peat moss in the mix, the more acute the problem. Mixing it well 50% with your soil is a good compromise. If peat dries out it shrinks and becomes difficult to water. At this stage if it is not planted, go ahead and put it in a wheelbarrow or the like and use the hot water, then mix in soil and refill. Any wetting agent will not address the problem of letting it get too dry again.
