Soil Alkaline 7.5

john77_2010August 25, 2012

I have several citrus trees in my backyard: Minneloa Tangelo (darwf - planted 8 yrs ago), Washington Navel Orange (darwf - planted 8 years ago), Nagami Kumpuat (planted 8 years ago), Lisbon Lemon Tree (three years old)and two Black Mission Fig trees (planted two years ago). All these trees in the back yard are not over 4 feet tall. I have been following the prescribe water schedules accordingly. Recently I tested the soil with a meter and its reading was 7.5+ Alkaline. I have a desert landscape in my front yard and my mesquite tree (planted it when it was a twig now 40+ft tall - planted 8 years ago), cactus, ocotillo, agaves grow beautifully and rapidly with new growth every where but in my backyard my fruit trees are struggling to grow more than an inch or two with proper watering and quarterly food delivery. New growth and leaves take place at a very very slow rate with many 0-7 fruit per year. Every spring the trees start with tons of fruit but they all fall off within 30 to 60 days afterwards. In the passed I have used a product sold by Garderner's World call Dispursel (qtrly application)(it is similar to gypsum) and it helped my citurs trees in my other homes to yeild boxes full of citrus fruit when my trees were not yeilding any fruit but in this home's backyard the citcus trees are not doing too well.

I called several nurseries in town and they advsied me that the soil is too alkalinized for citrus which like it around 6.5. They told me to add soil sulfur or if I drank coffee to add the used coffee grinds around the trees. Does coffee grinds really work to lower the alkaline from 7.5 to 6.5?

How much soil sulfur should be added to lower the 7.5 level to 6.5 and how frequently should this be applied?

Could you share with me how to help my trees grow at a better rate than an inch or two per year for the past 4-5 years. I have had cirtus trees before and planted them before in my other houses and they have taken off to grow 20 feet tall. I live right next to South Mountain (Phx AZ) and so the soil needs some conditioning compared to my other houses which were cirtus orchards before the houses came in.



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Adding sulfur works but it is slow reaction(weeks to months). B/c it requires bacteria to breakdown elemental sulfur to make acid. And once its used up you have add more.

Have you researched folar sprays. A lot of forum members recommend Foliage Pro. With this you can directly feed your tree via leaves rather than roots where an alkaline soil/water supply would lockup nutrients to citrus trees.

    Bookmark   August 25, 2012 at 5:29PM
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When you planted the citrus trees, did you pay attention to what variety of rootstock the trees were on ? For Arizona desert condidtions, the variety of rootstock is a bigger factor in the vigor of the tree than what variety the scion is (above ground portion that produces the fruit).

"Dwarf" trees on "Flying Dragon" rootstock are a generally poor choice for in-ground planting in Arizona. The rootstock doesn't do well at all in alkaline soils and even if provided appropriate soil is slow growing as well as "dwarfing". Most of the other rootstocks on trees offered at local nurseries are a variety of trifoliate (C-35, C32 and Carrizo are the most common). Although not "dwarfing", these rootstocks are best in California conditions, which is where the trees were most likley propagated. They have difficulty with Arizona soil and will need ongoing special treatment to thrive.

If you buy new citrus trees in the future, it is worth it to search for trees on Sour Orange roots. Lemon and grapefruit trees also do better on their own roots here compared to C-35 or Carrizo.

For the trees you already have planted, yearly application of soil sulfer and working in organic material will help with ongoing pH issues. Applying foliar spray containing manganese and zinc and soil application of iron and magnesium in the spring will help with pH induced mineral lock up.

    Bookmark   August 26, 2012 at 12:41AM
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Thank you for the feedback. I am at a loss as to the root stock of the trees and how it plays a huge part in AZ especially in ground planting. I bought the trees at Baker Nursery (40th street and Thomas)and they recommended these citrus trees for my backyard since I was looking for a citrus trees that would not grow as big as regular citrus trees but the salesperson never said anything about root stock or these trees struggling to grow in AZ. I am not sure where Baker Nursery gets their dwraf citrus trees.

    Bookmark   August 26, 2012 at 7:05PM
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The best thing you can do for your citrus in the high pH soils of AZ is to apply chelated minerals a cupla times per year. In the 7.5 plus pH range citrus cannot absorb the "normal" minerals they need from the soil, unless they are chelated. FYI in the Rio Grande Valley of Southern Texas they grow citrus in soils of 8.5 pH with water of 8 or more; it is costly, as they must put chelated minerals, especially iron. I would also put a good quality foliar fertilizer every 15 days; I like Bayer Bayfolan Forte; others here like Foliage Pro... there are lots of good ones; but the tree absorbs essential minerals easier through the leaves than through the roots in high pH soils.

    Bookmark   August 26, 2012 at 11:46PM
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Thank you I will try the things you mentioned.

    Bookmark   August 29, 2012 at 1:46AM
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I forgot to ask where can chelated minerals and Bayer Bayfolan Forte be purchased in Phoenix AZ or online?
Thank you again. I am very grateful. :)

    Bookmark   August 29, 2012 at 2:07AM
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Don't know the answer to where to purchase in AZ; I get mine in Guatemala.

    Bookmark   August 29, 2012 at 11:55AM
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Ebay is your friend.

Iron is the only micronutrient that is problematic to deliver in a usable form in alkaline soil. Iron doesn't work well as a foliar spray and is horribly staining. I've never seen the proper chelate offered in an Arizona nursery, which is curious. Ferriplus or Sequestrene 138 is what you want, although they are a bit expensive. Follow the directions for soil application. The stuff will stain anything it touches red if it gets wet. Late winter ~ early spring is the most critical time for iron deficiency. There is actually plenty of iron in most Arizona soils, but the combination of cold winter soil and alkalinity totally locks out availability, especially for some rootstocks. Only the chelates in Ferriplus or Sequestrene 138 are effective at pH > 7.5, other chelated products are intended for areas that don't have our alkaline soil issues. The problem subsides somewhat as the soil warms.

Zinc, manganese and magnesium are also common problems in winter alkaline soil but are easily and very cheaply cured with simple foliar sprays. Zinc sulfate and Manganese sulfate are cheap on Ebay. Magnesium sulfate is epsom salt, available at any drug store. Zinc and manganese can be applied together, magnesium is best on it's own. Wait at least a few days between applying the zinc + manganese solution and applying the magnesium. Magnesium works very well as a foliar spray, but also works well applied to the soil. Zinc and Manganese work much better as foliar sprays.

For Zn + Mn, mix a solution of ~1/2 teaspoon of each mineral salt in a gallon of pure water. Purified water from a vending machine is much preferable to local tap water. It helps with absorbtion to add 1/2 teaspoon of urea per gallon to the mix, if available. Spray the leaves to runoff after sundown. Application 3 times a year works for me. Early spring application is the most important.

There are premixed, all-in-one micronutrient products available at nurseries and garden centers, but in my experience it's worth the effort to order the chemicals to make the proper application, separate from competing minerals. It is much more effective. The chemicals are cheap, just a bit of hassle to order.

Here is a link that might be useful: Ebay Ferriplus vendor.

    Bookmark   August 30, 2012 at 3:13AM
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pgde(Tucson Zone 9)

John: For soil sulfur calculations see below. Available cheaply at Ace Hardware here in Tucson in large bags (30 lbs I think). Other chemicals available on eBay. I use Iron sulfate (used to use chelate but it got too expensive), zinc, Epsom salts (from CVS) and Arizona's Best Citrus Fertilizer. I apply all of the above 4 times a year. Labor day will be the last fertilizer before winter. While I haven't posted any recent pictures, do a search on my name to see the results. Will probably take some on Monday and post them. Best of luck.


Here is a link that might be useful: Soil Sulfur Calculator

    Bookmark   September 1, 2012 at 9:57AM
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