Plant watering

David R. Hershey dh321 at PGSTUMAIL.PG.CC.MD.US
Sat Jan 13 01:02:38 EST 1996

Most devices that automatically water potted plants use subirrigation. 
The simplest method is to set the pot, with drainage holes, on a
subirrigation mat and keep the mat wet. The pot will absorb water to make
up for that lost by the plant. A good subirrigation mat can be made from
Pellon, available at fabric stores. It needs to be washed in a washing
machine first to remove toxic fire retardants. A strip of Pellon can also
be placed in the bottom of the pots and allowed to protrude from the
drainage hole. The protruding strip can also be allowed to hang into a
reservoir of water, so no mat is required. The irrigation solution is
often a fertilizer solution so the plant receives fertilizer along with
the water. 

Commercial greenhouses often use a spaghetti-tube system which uses 
thin black polyethylene tubing with one or more tubes delivering water to 
the top of each pot. The system is turned on daily with a time clock or 
can be activated by a spring-switch which activates it when a pot loses 
weight. A solenoid valve is used to control water flow.

David R. Hershey
Snail mail: 6700 Belcrest Road #112, Hyattsville, MD 20782-1398

Adjunct Professor, Biology/Horticulture Department
Prince George's Community College, Largo, MD 20772-2199

Email: dh321 at

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