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Eugene, OR

Hi, This has probably been posted here before but I just ran the numbers for the amount of water required for 2" of water per week and figured I would post the multiplicaton factor for others to use. Turns out I was overwatering a bit so it may be useful for others as well.

To calculate the amount of water required per week to meet the 2" requirement, multiply the area of your patch in sq. ft. by 1.24676. That will give you the gallons per week required for your patch.

square feet x 1.24676 = gals per week

Obviously the 2" per week isn't set in stone and will vary for your soil type but 2" seems to be a good rule of thumb for newbies like me to go by so we don't drown our plants.

Good luck everyone!

Brian

7/28/2004 3:51:57 PM

Western Pa.

I've always heard you need at least 1" per week. By placing a jar, coffee can, etc. out and running your sprinklers you can easily figure out how long your pump has to run to get 1". My high pressure sprinklers would have to run 1 hour for 1/4" of rain. A good rain guage cann also be had for around $10.

7/28/2004 7:23:28 PM

Eugene, OR

Good point. I'm using t-tape so the jar would never fill up! I had no clue how much water I was using, which is why I ended up doing the calculations in the first place. 1500 feet of high flow t-tape lines at 40 gph per 100 feet means I was watering a bit too long!

7/28/2004 10:12:52 PM

Western Pa.

If you get the rain we're getting, the jar would fill up fast! I have about 1000 sq. ' of dripline this year (plus some melons and tomatoes), and I have found that if I dump 100 gallons of water, the ground appears good and damp.If summer ever gets here, I have an additional 100 gals if the first doesn't seem to be enough! It's always good to dig up a ball of soil and give it the squeeze test. It should be damp, but not wringing wet. Too much water can be worse than not enough!

7/29/2004 1:36:36 AM

Western Pa.

Forgot to mention the 100 gals is for 4 AG plants, 2 melons and a dozen mater plants!

7/29/2004 1:38:08 AM

Montoursville, PA

Nearly every Bio-Product lays claim to using substancially less water and fertilizer. If one uses such products one should surely come up with factors to cover these claims.

Further making watering interesting is that T-Tape on the soil still has some evaporation. Underground watering loses very little to evaporation. This needs factored in.

All of these and other comments need to be factored into the humus content of the soil. High humus less water. Low humus more water. Clay and sand as mentioned above are quite different. I suspect this is why no absolute charts abound for us to follow. The squeeze test is still as good one as is the dampness on the back of the hand found a few inches into the growing medium.

Most growers are more observent or will become more observent than most garden article writers would ever know from their desktops. Touch, feel and squeeze while watching the leaves. Most should learn in half a season or less what is good for their specific patch. An inch of water per week would not be a bad place to start. What to do then when mother gives you six, in six hours???? Yep we have that to deal with too.

12/1/2004 11:11:22 AM

Follansbee, Wv

Fortunately I am blessed with fantastic drainage. Even after the 12+ inches of rain Ivan dumped on us, I was able to walk on the garden the next day. Even a scoop with a shovel produced no pooling water in the hole. The soil was definately wet, but not muddy. Of course the slight slope of the ground doesn't hurt!
I'll be experimenting with watering amounts this spring, hopefully with a new drip system, revised with the recommendations of Doc. Thanks again Doc.

12/1/2004 6:59:45 PM