I prefer Polyon and use a 10-12 month 18-4-9 with micros.  I have used it on at least 5,000 field grown and potted plants over a period of 8 years.  It is superior to Osmocote because Osmocote releases its salts based on moisture while Polyon releases based on both moisture and temps, the latter factor is what you're after.  When the plant is dormant during cold soil periods and needs little to no nutrients, Polyon shuts down.   

As far as I'm concerned is safe. Don't pay attention to everything you read. Do your own research and test,  then draw you conclusions.
I test my soil regularly every 5-6 year. I use Cooper 2-3 times a year in 2005 the copper levels in my soil were medium (Normal) in 2011 also medium. My fruit test in 2011 showed no pesticides or fungicides detected in the fruit. I'm nor required to do these test but I do them because my family eats what I grow.
If you apply according to label I feel I'm OK. If you are going to be out there spraying every week then you may be asking for it.  I think there is some use allowed of Copper in organic farming.

 There is a lot of panic out there and people repeating what they read in a web page or an article. The fact is that in a wet summer like we had last year if you don't spray you get a lot of disease probably worst than copper.

Yep, if someone on the internet says it and it's repeated, then it must be true.

Thank you for those words of wisdom, and rational thoughts.

Kocide is effective and been used for ages.

Mark   

I'm new to avocado growing but the pruning I've been doing since they went in last year has paid off in a nice balanced profile with thick ever increasing trunk girth and that concerns me about yours.  It sure is leggie which suggests too much shade and/or nitrogen and/or a poor root system.   I'd take it back a couple of nodes at the top to induce lateral branching.

Good luck,
Mark

I've been trying to figure out if certain plants can alter pH, or even absorb some of the chemicals added to city water.

Curious, what harmful chemicals are you talking about and exactly what harm are they doing to your faves?

The only "harmful chemicals"  I have in my well water is very high amounts of Mg and Ca bicarbonates.  Bicarbs really aren't harmful in terms of plant health..... just influential regarding element antagonism and a nuisance regarding bicarb salt buildup in and on pots, evaporative wet pads, etc.

I'd be concerned that your companion plants would be robbing your faves of nutritional elements and moisture.

Mark

Thanks, considering I grafted that plant last year on pencil sized rootstock, never before having done veneer and cleft grafts....I'm damn proud of it.  The trunk is about 1" girth and the graft is so solid I can't see it anymore.

I agree, it's hard to beat a Reed for size, taste, and texture.  I mail order them SoCal farms but they're hard to find and when you do find them, they're very pricey!  If you have any sources for Reed fruit I'd love to have them.

March 2012, I grafted Reed to a 6 month old Florida seedling that I started from seed and it has set quite a few fruits.  Veneer graft is super strong and thick.  Per the grower "norm", I'm inclined to pull all fruit to let the "energy" go into roots and foliage but to me that decision depends on plant health, foliage/root mass, and vigor.   Except for the impending summer heat which starts soon and lasts until September, my greenhouse avocados have the best of conditions.  IOW, they're not stressed and have a robust root system thanks to the custom backfill and RootBuilder pots.  New foliage output has just begun after spring foliage drop.

Input appreciated!   And as an aside, if you need info on the merits of root-tip termination/training, I'm your man.   







Thanks,
Mark

Yep, ammonium sulfate would be an excellent choice and one I use often.  Buy it by the 50 lb. bag size at feed stores.

I had many acres under drip irrigation in San Diego, where the soil was very sandy. Still very beneficial, you just need to use more emitters as the soil is not absorbent. Also you can use micro sprinklers for better soil coverage. Low pressure systems don't mean you necessarily have to use drip emitters.

Good advice.  I run miles of drip and paired my emitters with my soil profile which is heavy clay loam - 1/2 gph and 1 gph, mainly Woodpecker brand.  He could probably get by with 5 gph.  Many other factors are at play like well volume, psi, etc.   Pro advice is needed to design the system correctly unless it's for home use.

Hello All;

Why is My Lilla Avacado Tree Leaves Turning Yellow & Falling After Neem Oil App?
How can i reverse the effect & is Neem Oil Safe ,  i saw some bugs eating at the leaves & applied a lil neem oil & today some leaves look Droopy & yellow & the fall to the Touch.

Should i try to hose off the remaining leaves to get rid of the neem oil ?

Thanks for your help..Ed

You need to use extra virgin neem oil.

I applied Actosol   http://www.arctech.com/actosol.htm  over12 months ago its Humic and Fluvic acids. If it does 1/2 of what it says.....

And there's the rub, "claims", as in another sales pitch.  I'll preface this by guessing it was the urea that did the trick for you.  Most soils are very deficient in N. 

Here are a few myth busters about snake oils aka as non-conventional soil additives.  Believe me, wanting to believe the claims I've given many a try. 

Some of the best U. of Cali tropical farm advisors/authors weigh in, like Ben Faber and Gary Bender.  Excellent!

Snake Oil, Horticultural Myths, Horticultural Urban Legends, and Persuaders in our Industry
Jim Downer Ph.D. Coopera􀆟ve Extension, Ventura County

http://ceventura.ucdavis.edu/newsletters/Topics_in_Subtropics39882.pdf

The word about hundreds of non-conventional soil additives done by the U. of Wisconsin.

http://www.soils.wisc.edu/extension/pubs/2006noncon_with_ref.pdf

Mark

Mark do you know if by diluting the sulphur granules or pellets in water and doing a soil drench would be a quick way to acidify the soil or is that a quick way to kill the plants? The sulphur that I am using dissolves quite easy once it is hit with some pressure with a water hose.

Guess you could but be sure to check rates out.  Tables are available on  line that take into consideration your soil structure and composition, native pH, where you want to go and recommend the amount to apply.   I have broadcast sulfur pastules on lawns.  You  could also make up a drench for boom apps using wettable (sprayable) sulfur.  The danger is creating a nutrient antagonism affect and getting a drop in the pH so much so fast that  it actually burns fine roots and root hairs, especially if you're in sand.  Recommend you become familiar with this concept - http://www.totalgro.com/concepts.htm   

Green manure crops is also an option but it will take years of successive plantings and tilling to see any pH drop.   Before planting a commercial ag crop I planted yellow sweet clover, hairy vetch and elbon rye, the intent being to get somewhat of a biological soil plow going and add a bit of N as well as humus.

As an aside because I know it's gonna come up sooner or later.....I've found all of the so called "natural, organic" unconventional soil additives to be nothing more than high priced snake oils.  I do apply mychorzzial fungi before planting though.  MycoApply SolubleMaxx is what I use.  Whether or not it's making any difference remains to be seen.  Can't tell any difference between a control group when planting grapes.  My electron microscope crapped out so it's hard to tell what's going on, makes me feel good though (and makes the vendor feel even better). 

Lots of options........

Mark 

I'm exploring a few question about the subject:
First is the sulfur in fertilizers the same type of sulfur to acidify the soil. Several elements come with a good percentage of sulfur like manganese Temagtan. I use sulfur coated urea. Would that acidify my soil over a period of years?

Carlos, the sulfur found in fertilizers is a sulfate form and yes, it might lower the pH.   If it's not stated on the bag, recommend you call up the manufacturer and find out the CaCO2 ton/acre equivalency.  Anything over say......800lbs. is gonna be acidifying with an azalea food around 1,200 lbs.

It's my understanding that sulfur coated urea is acidifying.   Again, a moot point IMO as calcareous soil has a powerful buffering affect..... plus it all depends on your rootstock's nutrient uptake profile which is really what you should be focusing on.  Attached is chart showing that your choice of WI rootstock, Waldin, should have a low potential for Ca uptake (and N).  I've looked at your photos and see no indication of chlorosis.   Tissue analysis looks pretty darn good too.

Second:  too much of anything is bad. In my tissue analysis there is a line for sulfur and it can test high meaning it will have an adverse effect on the trees. I'm attaching the last test results so you know what I mean.

Not sure what that means.  Adverse, how? As in nutrient antagonism regarding other elements?

Third: I doubt we can add sufficient sulfur in our rocky soil to have a meaningful effect.

Yep.  There was a fellow who was determined to grow apple trees in calcareous soil near me, so he brought in huge tankers of sulfuric acid and broadcast it using large booms.  It was a short term affect and of course ridiculously expensive.  He gave up.

Fourth: Is there anything that can be applied with the irrigation water?

Sulfuric acid.  I use 78% battery acid bought from an auto parts store in 5 gal. bags and inject it with a Mazzei.  My use is to help clean out my emitters.  My well water is super high in bicarbonates.

Talk to Dr. Mark McFarland at TX. A&M.  This guy is a real pro when it comes to soil science.  Also, I know you have resources in Florida but their testing labs are excellent and cheap too.  http://soilcrop.tamu.edu/staff/mcfarland-mark-l/

Good luck,
Mark