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Omaha, Ne.

What kind of pump would need to run a sprinkler for a 20x30' patch. This one
Shurflo 86-8398 Water Pump Revolution has 3 gph would this be over kill or to weak? Thank's

1/21/2012 6:11:54 PM

Omaha, Ne.

oops 3 gpm

1/21/2012 7:51:24 PM

Greenfield, Mass

Well 3gph would sure be too weak, but 3gpm could do alright if on the right timer.
It depends a lot on how you set up the sprinklers.
A 20/30 plot is 600sq ft. One inch of rain on that would be 144*600*1 = 86,400 cubic inches. Which is about 374 gal (if I didn't screw up the math somewhere).
So if you want 1" of rain per week you need to run the pump for only a total of about 17 min a day
Depending on your sprinkler setup you may reduce the flow a big, so you should re calibrate based on the tank level change.

1/22/2012 9:12:21 AM

Greenfield, Mass

* "a bit", not "a big"

1/22/2012 9:13:49 AM

Menomonie, WI (mail@gr8pumpkin.net)

Something is wrong with the math..17 minutes at 3GPM is 51 gallons a day. 51 x 7 is 357 gallons. This won't give you one inch of water a week. I think you would have to run it atleast 30 minutes a day to give you 700 gallons a week.

1/22/2012 9:25:38 AM

Greenfield, Mass

humm... maybe I should run through it backwards:

357gal * 231cu in= 82,467cu inches of water a week
20ft*30ft= 600sq ft
600*144=86,400 sq inches of garden
82,467cubic inches of water/86,400sq inches of land= 0.95448 in of rain
Looks like I rounded off something somewhere, but it's close
700gal would be nearly twice that

But anyway, that pump with a good timer seems like it would work well, and be able to handle a larger patch if you wanted to expand.

1/22/2012 12:19:45 PM

Ashby, MA

Doing my own calculations for my own garden I realize that I need to step up the amount of water this year. I have one question. When considering the size of the patch in the calculations should we reduce that number early in the season since the plant is not taking up the entire patch? Or should we be consistent and water based on the size of the total patch even early in the season?

1/23/2012 9:32:18 AM

Greenfield, Mass

I've yet to grow an AG myself, but I'd say it depends on your sprinkler setup. If your watering the whole patch for the whole season you'll want to make sure the parts that are used are getting the 1 inch (or whatever you want) a week. If you add sprinklers (or misters, or drippers) as it grows you'll want to work out how much land your watering at a given time.
I think it would be best to water the unused ground to some degree. It doesn't need as much water, but you don't want it to dry out. If it kept moist you'll germinate weed seeds and can pick them out before the pumpkin gets there, also some moisture will keep the soil healthy (i.e. worms, and microorganisms). But you don't want to over water as that will lead to nutrients leaching out.

1/23/2012 10:14:58 AM

Omaha, Ne.

Thanks everyone learned a lot

1/24/2012 10:08:21 PM

Greenfield, Mass

A thought I had last night (I'm still not an expert):
the highly controlled watering setups are more for a fruiting plant; so the pumpkin doesn't explode. With most plants a more infrequent watering is beneficial as it stimulates root growth (in dryer conditions roots grown down in search of water). I suspect this is true of AG's as well. So it may be best to only water heavily once or twice a week before fruit is set.

1/25/2012 8:24:21 AM