North American Fruit Explorers mailing list at ibiblio

["Donna &/or Kieran" <holycow@cookeville.com>]

I have always used borax from the grocery, but it didn't seem to help the 
chestnut crab last year.  Since borax is so water soluble, it might have 
washed away in the few months we had good rains.  So I was interested when I 
read about spraying with Solubar I think it was called, you just spray it 
when the fruit is tiny and that's all the boron the crop needs that year.
   I'm sure either way I'll keep applying the maxium rate of boron on the 
garden and non fruiting trees every year for several more years at least. 
The absolute maximum rate for boron is 4 lb per acre, but if you 
accidentally overlap a row with the tractor or spreader or broadcasting, 
you'll kill everything in that spot.  So Neil Kinsey says in practice the 
max rate is 2 lbs per acre.  That's 11 lb per acre of borax.  This is why I 
sprinkle it like fairy dust, it's very hard to figure out how to spread 
something so thinly.  The fertilizer dealers mix these small quantities into 
lime or fertilizer for even spreading.
   Boron deficiency is common or rare depending on where you are.  It's 
extremely common in the southeast in red and yellow clays, but Florida is 
also desperately short.  On the other hand, in dry areas out west they 
aren't likely to suffer much from boron deficiency.     Donna, TN Z6

P.S.  Keep boron away from walnut trees, it's bad for them.