how to convert pounds to an acre down to ounces per square feet?

I am trying to convert '4# borax per acre' to x amount per 10 square feet to spread under my peach tree.

I know I could ask google or something and get a quick answer but I would like to know the steps in order to get to the answer.

I'm assuming it's tablespoons by the time it's downsized to a smaller area.

Just so I don't go with my usual 'maybe a handful' method I thought maybe someone here likes math and can help me see the process.

...and I did try, there are 43,560 sq ft in an acre, 10,890 sq ft to a quarter acre, so that's down to 1# borax.
then I got lost.

thanks😊

and a cup of borax apparently weighs 7.2 ounces.
I'm hoping to end up with spoon measurements though.

Seems to me, I would start with how many square feet are in an acre which I was told is 2.2956 square feet.

Then divide the amount of Borax by 2.2956.

Once you get that amount that can be divided into cups or tablespoons, teaspoons, etc.

I hope that some math wizard will say yes that is right.

Sometimes I'm so grateful for the metric system...

4lb is approximately 1.8kg

An acre is 4047 square metres

So 1800/4047 is 0.44, so that's the number of grams you need per square metre. Which isn't far from 10 square feet, assuming you don't really mean 10ft x 10ft.

I'm guessing a teaspoon would weigh around 5g, so you'd probably only need fraction of a teaspoon around your tree.

Or maybe I'd just wash my glassware with some borax to shine it up a bit then sploosh the greywater around the tree.

Edited because some days I'm a total dumbass...

Here's the math...


  4 lbs              16 oz/lb                 64 oz
-----------   *  -----------------     =    ------------  
 1 acre         43,560 sf/ac          43,560sf

=>

  64               x
---------  =  ----------
43560          10

=>

64 / 43560 * 10 = 0.015 oz per 10sf

that's not much...fraction of a tsp, probably.

Easy in metric system:
4 lbs = 1.8 kg
1 acre = 4047 m2
1.8 kg/4047 m2 = 0.44 g/m2
10 sq ft is around 0.9 m2 so for this area you would use 0.9*0.44 g = 0.4 g

Specific gravity of borax is around 1.8 g/cm3 so 0.4 g  would be around 0.22 cm3. Measuring spoon has 5 cm3. Precise 0.22 cm3 would be difficult to scoop with a tiny measuring spoon. I face these problems when preparing test enamels for ceramics. In your case I would use 1/8 measuring spoon (0.625 cm3) per 3 trees.

For plants boric acid should be used, as borax has lower boron bioavailability.
When I was using boric acid for my pistachios I dilluted half a spoon in a 5 gal bucket and used it for watering one tree.

thank you all!!!
I knew I could count on  answers from real folks😊
Who needs google!

The 10 square feet per tree is really a 3 foot circle of bare dirt around my tree to try to deter peach tree borer larvae...squared off to 3 foot by 3 foot is 9 square feet but for my math I thought calling it 10 square feet would be close enough and I'm not up to figuring out square feet of a circle.

I'm happy sprinkling a scant teaspoon of borax now.

Judith Browning wrote:
The 10 square feet per tree is really a 3 foot circle of bare dirt around my tree to try to deter peach tree borer larvae...squared off to 3 foot by 3 foot is 9 square feet but for my math I thought calling it 10 square feet would be close enough and I'm not up to figuring out square feet of a circle.

You're welcome! Bonus formula for you - the area of the circle is pi times the radius squared 3.14*(1.5^2) - so it's roughly 7sf

I think the one lesson I really learned from all this is why they do NOT recommend that you use borax in your grey water system. A regular dose of just a teaspoon or two is soon going to add up in a small garden!

Benedict Bosco wrote:

Judith Browning wrote:
The 10 square feet per tree is really a 3 foot circle of bare dirt around my tree to try to deter peach tree borer larvae...squared off to 3 foot by 3 foot is 9 square feet but for my math I thought calling it 10 square feet would be close enough and I'm not up to figuring out square feet of a circle.

You're welcome! Bonus formula for you - the area of the circle is pi times the radius squared 3.14*(1.5^2) - so it's roughly 7sf

Benedict,
thanks for that formula...
so 3 sq ft less than my really rough estimate...might be using a half teaspoon.

Peaches can use the boron though.

Cristobal, I do have boric acid so could use it instead.....there are several peach trees so can experiment.

Burra Maluca wrote:I think the one lesson I really learned from all this is why they do NOT recommend that you use borax in your grey water system. A regular dose of just a teaspoon or two is soon going to add up in a small garden!

yeah, probably not good at all in a grey water system.
We have it on hand to spray lumber as insect protection...very concentrated compared to soil amendments.

for the peaches I think I'l mix with water to apply as I 'm not sure how I could sprinkle that tiny amount evenly?

Use some on your pear and apple too. Prunus are the very few genus that boron is mobile and gets moved to the fruits. Replenishing it helps with healthy growth and next year's fruiting. Boron mainly acts as structural component of the cell wall: B and calcium both bind to pectin with calcium forming tight binding for rigidity and borate crosslinking with sidechains of two pectins to provide elasticity. You will find boron deficient plants with stiff and puckered new growths. Strawberry is a good indicator too since the deformed fruits are very characteristic.

There are many types of boron products. Plants uptake boron mainly as boric acid as it is small and uncharged, through passive diffusion or mass transport with water. When using borax for soil amendment, it is more slower acting since calcium in the soil will buffer it. Rainfall can leach boron quickly, so if is better to divide the applications in spring to early summer. I only use boric acid for correcting emergency and the concentration will be calculated carefully by the case since it gets into the tissues readily.

I actually have dozens of successful stories bringing plants back to health using boron but I don't want to overstate it as some silver bullet. Sea water, or ground water in arid or semi arid area have sufficient amount of mineral boron, and fertile soil, alluvial soil have boron from organic matter.  My area is none of the above and I grow too much high demanding plants, making it more critical. Just like other things, add only when the plants need it.

May, do you apply dry or dissolved in water?
and what measure for your trees?

I really don't see deficiency signs as you describe but wanted to give the peaches a boost.

Good to hear your soil has sufficient reserve. If you just need maintaining, 1 table spoon for 100 sq ft every other year is enough. Dissolve in water and apply evenly with a watering can. When plants transpire and uptake the boron, the excess will accumulate at the tips of the leaves and when it rains, it washes out and recycles back in the soil (drip line!). In our climate, toxicity is unlikely because of the high rate of leaching.

For me, I did 5 applications each of 4 lb borax on one acre from Feb to June last year, based on my local rainfall/temperature pattern. So about 2 lb of net boron per acre and 3 months prior to that I already put down hundreds of pounds of lime and gypsum to raise calcium level.  It was kind of high rate because I need to get it deep in the soil profile. I don't need to this year. My oldest peach tree finally has hundreds of flower buds surviving -12F and multiple warm-ups and freezes, after 3 years of nearly zero harvest. It might be able to fend of plum curculio without any protection as well.

If you want to fo it organically, pomace, castings from worms fed with fruits, alfalfa pellets or manure from rabbits fed with alfalfa all have relatively higher level of boron, and other nutrients. A 50 lb bag of alfalfa pellet with 15% moisture and 50 ppm boron contains 1 gram net boron. It's analogous to treating anemia with iron supplements. If the situation is mild, correct it with diet; if severe, take concentrated form for speedy recovery.

thank you May!
I mixed a scant teaspoon boric acid in 2 gallons of water for each of my three largest trees.
Maybe should have waited for the next rain?