Boron Application Rates


So I paid for a test on my homemade container soil, and it came up marginally deficient in Boron of all things, 0.5 /1.0 when it should be around 3-5.

I wouldn’t recognize a B deficiency from a hole in the ground, but I paid for the test so I might as well get the numbers right. So I’m standing here with overpriced Boric acid roach poison (99% Boric acid) I got from Ace Hardware.

What kind of application rates do you recommend for my 20 gallon containers? I’m looking for conservative, but not useless.

3lbs per acre :wink:
That’s what WSU says, unless the test indicates more. I’d like to see you convert that to 20 gallon containers now :slight_smile:

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A LITTLE BORON GOES A LONG WAY! I just did the calculations for a product I was using the other day (based on the recommendation from the manufactuer) it came out to .16 dry weight ounces / 2 gallons of water. Yes that is a point before the 16.

My Boric acid is about 3x more than Borax sooo… That works out to 1-2 grams for my watering can. Maybe 1/4 -1/2 teaspoon.

The WSU recommendation was of actual Boron. I think Borox s a little over 10% Boron.

Interesting that boron deficiency in pears manifests very similarly to pseudomonas. We have both problems in my area, I assumed it was the latter when my pear blossoms were wiped out this year.

The alternative application rate I saw was 12 mg per kg. So my 2000 mg Boric acid in the watering can spread over 10 twenty gallon containers would be about right. (I figure only the top 6-8 inches counts in the calculation).

Seems strange to apply supplement as a percentage of soil mass. Doesn’t the soil mass vary hugely with hydration?

I guess they figured a certain number of us gardened in containers. I saw a grape specific one that had a pound per acre figure for foliar application----but it works out to a gram per plant.

It’s an old thread but it might still be worth reading Boron deficiency / Blossom Blast?. 20 mule team is worth it.