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dwighthe

Raised bed dries out too quickly.

dwighthe
8 years ago

In an earlier tread kimmq posted the following

"2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up."


I have a 4X11 ft concrete block bed that dries out too fast. Three seasons ago I originally filled the bed with 1/3 vermiculite, 1/3 peat moss and 1/3 compost(cow, cotton burr and chicken litter). From the beginning I've had problems keeping it uniformly damp all the way to the bottom of the bed. In dry weather the bed will dry out all the way to the bottom and is then is very hard to re-wet. I've added leaf compost each year. I recently tried the procedure that kimmg recommended above and all of the water ran out in less than 15 minutes. I also filled a jar half full with dirt from the bed and shook it up with water. It separated out with about 10% sand, 30% of what appears to be organic matter that sinks and about 40% floating material.


I also sent a sample to the Louisiana extension service. The results showed very low nitrogen, but high to very high phosphorous, potassium, calcium, and other minerals

Kimmg's recommendation with fast draining soil is to add more organic material. I don't see how in this case this will help. Most organic material will add to the excess minerals that I already have, and in any event the bed is already 70% or more organic material. I can add peat moss but if the bed dries even a little the peat moss is extremely hard to re-wet.


Can anyone suggest a fix?


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