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Phoenix, AZ

Lime in the form of Calcium Carbonate, I understand, is not as available to plants as others forms of calcium. Is this true?

In my case, I have 6400 PPM of Ca in my soil and is the major cation with no Mg, K, Na ratio issues. It is also confirmed that I have significant amounts of natural lime in my soil, per the lab I use here in Phoenix. I have tested this myself by putting pure Citric Acid on my soil, add water and watch a little volcano form. However, my soil sits currently at a Ph of 7.1.

My plant initially took up all nutrients fantastically and was confirmed by a foliar test. After 45 days, the plant started to lose energy and leaf burn developed. Another foliar test confirmed that my Ca had dropped WAY off from 6.5% to 1.6% (see my diary). What I am trying to do is eliminate all possible issues causes.

I am thinking that "maybe" the initial good growth came from the way I set up my pit. What I did was take a 2 FT X 2 FT area around where I was going to plant and I added in Citric Acid. I did this only to adjust the Ph down. However, I am wondering if by doing this, I allowed the calcium to chelate and create Calcium Citrate. This form, I understand, is very available to plants. Would this have allowed the uptake so well intially? Then as the roots outgrew the 2 FT square area, they found calcium to be unavailable?

It was such a great looking plant and now it has lost so much energy. ANY thoughts on this is appreciated.

4/29/2006 11:56:55 PM

[email protected]

Humic acid in soil does chelate all mineral (metallic) elements in soil in time. So while Calcium carbonate is not chelated in the form of limestone as delivered, it will in timke "chelate" none the less. It's a slower process. But it's a process that has worked quite well for a long time. If a soil is naturally low in soil or we just want to push more clacium at a plant, there are also chelated calsiukm solutions available to do that. But they won't correct acid soil issues.

4/30/2006 12:22:42 AM

Phoenix, AZ

Another thing, my soil was covered for 15 year with plastic so it was pretty much dead with no OM. I only in the last 14 months added significant OM.

Also, in the time I have been trying to grow pumpkins here in Phoenix, I have always had problems with low calcium levels in my plant even though I have plenty in the soil.

4/30/2006 12:49:55 AM

Chico, Ca

Sounds like you need to consider spraying with liquid calcium.We fertigate through the overhead misters. Calcium does not translocate in the plant.

4/30/2006 11:23:49 AM