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TheWaterbug
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Please check my water/fertilizer math

This year I bought an [url=https://www.amazon.com/gp/product/B00065266U/ref=oh_details_o00_s00_i01]Add It 5016-HV fertilizer injector[/url] to use with my drip system, and I've been filling it with [url=https://www.liquinox.com/about.htm]Liquinox Grow 10-10-5[/url].

According to the Liquinox label I'm supposed to dilute one Tablespoon into one gallon of water, or a ratio of 1:256.

The 5016 is a 1 pint dispenser, and the [url=https://fertilizerdispensers.com/services/pdf/ai_AFI_2000_I-O.pdf]PDF manual[/url] says it empties in 35 gallons, for a ratio of 1:280, or just about right.

My corn patch is ~25' x 12', and I have four 25' lengths of Drip-a-long hose running its length, with 1 GPH drippers every 18". So I have 100' divided by 1.5' = 66 drippers. So if I run the system for 30 minutes, I should get 33 gallons through the injector, which should just about empty it.

The Liquinox label says to apply "once or twice per month," so if I fill the injector every two weeks, that'd be right on target.

Right? Or did I miss something major in my calculations?
Sunset 23/USDA 11a, Elev. 783', Frost free since 8,000 BC. Plagued by squirrels, gophers, and peafowl, but coming to terms with it!

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TheWaterbug
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Posts: 1064
Joined: Mon May 02, 2011 9:15 pm
Location: Los Angeles

And then on the watering side of things, I keep reading that corn typically wants "one inch of water per week."

If my patch is 25' x 12', that's 300 sf, or 43,200 square inches. If I multiply by 1 vertical inch and divide by 231 cubic inches/gallon I get 187 gallons, which suggests that I should run the watering system nearly 3 hours/week, which seems like a lot of water.

The top 1" of soil in my patch is pretty dry, but if I dig down a foot or so it's quite moist. I attribute that to the drip system, since I'm not spraying water all over the place, and thus have very little evaporative loss.

We get zero rain between ~May and September, but we do get some morning fog/dew, and the leaves are wet in the mornings. Temps have been in the mid-70s most days.

Everything [url=https://www.helpfulgardener.com/forum/viewtopic.php?p=260843#260843]looks really healthy[/url], so I'm inclined to leave things as they are, but I'm just wondering if I'm interpreting the "typical" requirements correctly and doing the math right.
Sunset 23/USDA 11a, Elev. 783', Frost free since 8,000 BC. Plagued by squirrels, gophers, and peafowl, but coming to terms with it!

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