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[Alan Haigh <alandhaigh@gmail.com>]

In an article published in the summer edition of Pomona, Jim Fruth used a statement I made on this site and and posed it as a question to him, which it was not.  I just thought I'd set the record straight because I disagree with the fundamental tenet of his article and to the way he evaluated the observation that blueberries often thrive in near neutral soil.

 

He suggested that blueberries could only do well in neutral soils if the calcium was somehow "deactivated".  He seems to be saying the the entire rhizophere has to provide the blueberries equally the iron they need that is often tied up by calcium.  In other words that iron availability has to be homogeneous throughout the soil.

 

My theory, which has already been tested successfully in surface applications of sulfur to correct iron deficiency in pin oaks in alkaline soils by Carl Whitcomb, is that only a fraction of the soil profile has to have available iron to serve the needs of  acid loving plants. 

 

In the case of blueberries that I have seen doing quite well in soils with a pH well into the 6's, I believe that the fact that these plants are well mulched may be the key to their vitality.  As the mulch decomposes acids are released that free up adequate iron for the blueberries to get all the iron they need.  This is the simplest explanation, so until someone researches a contradicting explanation, it I'll run with it.

 

As far as the substance of Jim Fruth's article that I disagree with, at least in the conditions where I establish blueberries, it is his assertion that one should wait a year to plant blueberries in alkaline soils.  I would never waste a years growth to acidify a soil (the suckers take long enough to establish as is), and if the blueberries appeared deficient in iron in spite of amendments made at planting I would spray them with some kind of soluble iron.  This has never been necessary at sites that I amend with ample peat moss and granular sulfur, but it is what Cornell recommends when blueberries are incapable of acquiring iron from recently planted blueberries in amended soil.  They do not recommend waiting a year to plant.