Pure interior acrylic/latex water based paint, 1/2 interior acrylic/latex water based paint:1/2 water. 1/3 interior acrylic/latex water based paint:1/3 general purpose gyprock joint compound:1/3 water.

The 100% paint caused some back die back, I think because it was totally impermeable and the bark rotted.

The 50:50 paint:water brushed on very thin and lasted only 1 year before chipping and flaking.

The 1/3:1/3:1/3 mixture worked great. Good consistency to paint on in decent thickness, no real die back so I think it is a bit more permeable letting the bark breath some and the critters really don't like the taste and protected me from sun scald too. So far it seems to be standing up better durability wise as well.

Hope this helps someone.

P.S. In case you missed it I have updated my "My Backyard planting experience (so far) - Zone 4a/b Quebec" post with a 2014 year summary review for my northern fruit experience thus far.

Also, in a previous thread someone mentioned adding insecticide & fungicide also. I don't remember anyone mentioning how much insecticide-fungicide to aded.

Any suggestions/
Thanx
Mike

For the pre-mixed I took my paint mixing can (just a 28oz can left over from diced tomatoes). I put the pre-mixed compound and filled a half circle in the bottom of the can (eg. If you filled the entire bottom of the can to 1/2 inch, instead I filled only half the bottom of the can to 1"). Then I poured in paint to fill the other half up to the level of the joint compound. Thus at that point I had a 50:50 mixture. Then I eyeballed and just poured in some water and stirred, poured a bit more and stirred until I had a slurry that hung nicely to the stirring stick but was not too thick nor too thin. Approximately the same consistency as the undiluted paint.

Really it is not a real science and I don't think the exact proportion is that critical. If I was to start with dry joint compound I would probably mix it with water per their instructions to get a thick mud, then do what I did above, shove the mud to the side to make a 1/2 circle, add paint to get to 50:50 and then enough water to make it easy to work with.

This mixture dried in about 40-60 minutes on a sunny day at 0-2 degrees Celsius.

I guess that although I rail against it, I am becoming part of the "Google it" generation where it is easier to send an electronic shout expecting someone else to already have the answer rather than taking the time and energy to figure it out myself.

Not happy with myself

Mike

I suppose you mean Label rates per gallon,

I was thinking to measure the PH of the paint & joint compound (but how?).

Paint and joint compound might have a VERY high PH which would tend to neutralize the fungicides & insecticides, No?

Mike

FROM A "HOW TO" SITE: Most paint has a pH range of 8.0 to 8.8. The acrylic polymer used to make paint becomes unstable at a pH below 7.5.

FROM THE CALIFORNIA RECYCLING SITE: --->
New latex paint has a pH between 7.5 and 9.5. Paint tends to lower in pH during storage. Adding amines or ammonia can restore the pH.

FROM USG & NATIONAL GYPSUM : pH @ 25 º C ~7.5-9

Mike

This is something I hadn't give any thought to. I guess it would negatively impact organophosphates (maybe). I don't think it would be an issue with some and sulfur may well be improved by it. I'll look into this when I get some time.

I have a PH meter and could be used on the solution, but it would tell you nothing, my water, paint brand, etc. Plus I'm not mixing any up till the summer, all are fine now.

It seems that way, but it's not. Using a roller doesn't allow you to get down real close to the ground. A brush (although a bit slower) is the best way to apply it. I actually try to pull back some loose soil right at the trunk and paint as far below the soil line as is easily practical for borer deterrent. Also if you use the joint compound / paint mixture the product is too thick to efficiently apply with the roller. Brushing it on pushes and pulls the material up under loose bark bits and really covers things over nicely. It really doesn't take too long and gives you an opportunity to really see and inspect under your trees.

If someone had like 30 or more trees it would probably make sense to look at other methods, but for most of us brushing works best and is fairly painless.

I tried a few brushes but prefer a glue/flux brush for maneuvering around branches, crevices, and soil line. I kept my mix thick with consistency of cake batter.

"permeability" is totally anecdotal. All I know is the four 1 year old whips I planted and painted with 100% latex paint in the fall had the bark rotting and peeling come early summer and every one died. The peeling/rotting bark was ONLY under the painted area, 1 cm above the paint the bark adhered well to the trunk. Now it is possible that all those trees died over the winter by themselves and then the painted area just sped up the decomposition process, I don't know. I am also in a damp area so maybe that did not help. All I know is that none of the whips painted at the same time with 50:50 mixture of paint:water, or 1/3:1/3:1/3 paint:water:joint compound died nor had the same issue with peeling/rotting bark under the paint.

Myself, from now on I am not painting young plants like that with undiluted latex paint.

Anyone else want to chime in on their experience? Have you painted newly planted 1 year old trees with undiluted latex without issue?

Well as I said I was starting this project from scratch and not everybody is detailed in giving instructions. Back in 2012 I did a search and came up with 3 types of recommendations from the internet, straight latex paint, diluted latex paint, mix diluted paint plus joint compound. Did not know which was best so tried all 3. Don't understand why I could not find any comparison of the 3 options at the time and I have to be the one to do the testing but there you go.

Heck even now if you take a look at google search for ''paint fruit tree trunk''
1st link:
https://utextension.tennessee.edu/publications/Documents/SP307-G.pdf
University of Tennessee and no mention of dilution. In fact they say ''Use paint full strength for maximum protection.''

2nd link http://fruitgrowersnews.com/index.php/magazine/article/painting-tree-trunks-protects-against-rodents-borers
all 3 options are discussed and the Cornell university guy says ''we applied the paint at full strength''

3rd link from 2012 post here on Garden web: http://forums2.gardenweb.com/forums/load/fruit/msg0115085916619.html
''Paint does not need 50/50 with water color can be any you choose. 50/50 limit to make more paint volume.''

4th link:
https://answers.yahoo.com/question/index?qid=20101104170435AADGz8P

No mention of dilution.

5th link:
http://urbanext.illinois.edu/ (name redacted due to garden web spam blocking) /issue_07/winter_05_11.cfm

University of Illinois does not mention dilution. ''Apply the paint using a brush or other materials such as a sponge in order to get a thick coat for better protection.''

6th link:
http://www.starnursery.com/chemicals/specialty-products/white-latex-tree-trunk-paint-1-quart.html

No mention of dilution.

So of the top 6 google searches done TODAY, 3 have university agriculture guys not mentioning dilution or saying to use full strength and the other links mentioning full strength or not mentioning dilution either.

So I think it is pretty clear that not everyone dilutes. Having done the test of the 3 options in my particular environment (zone 4a/b, wet and cold fall - winter - spring, clay soil), I am going with paint:water:joint compound from now on and hopefully someone can take something from my experience when they are trying to decide what to use.

I'm just sharing my experience on what worked for me, explaining where I screwed up and what went wrong so others can learn from my mistakes.

Eg. in heavy clay don't amend your planting holes. Many references say mix up to 30% compost or good soil into your planting hole with the rest being the natural soil. Others say no amendments. Well this year I found that a 4' hole I dug and did the 30% mix had shrunk! 2 years later now, around the whole outer diameter of the 4' planting hole was a crack 1/2 to 3/4'' wide all the way around where the soil in the planting hole had shrunk and contracted away from the surrounding soil. Yeah, a 3/4'' air gap is not bloody good for roots trying to cross! Essentially I think that tree is going to be a giant root-bound plant. I tried to mash up the soil but as i said that hole was 3' deep and 4' wide so not the easiest thing to do. I'm hoping the worms will finally fill in the air gap and roots will cross. But learn from my mistake, NO AMENDMENTS (at least in clay soil), just put your compost and the like on the top of the surface and the nutrients will find their way down.

>>So I think it is pretty clear that not everyone dilutes<<
Yes, you've shown me.
I think most do here, unfortunately it hasn't worked out for you.

Here is an old publication on use of exterior latex and insecticide: http://ucanr.edu/repositoryfiles/ca2304p12-65471.pdf

They other mystery variable is the acrylic/vinyl ratio used to make the synthetic latex. Acrylic is more desirable for protection because it is less permeable. However, it is also more expensive. Generally, the more expensive exterior and quality interior latex paints have higher acrylic and might account for some bad experiences when used on trees. Therefore it would be better to use the cheapest, low quality interior latex paint if you are concerned about negative effects from paint. However, it is just a generalization that can't be confirmed because paint manufactures don't like to reveal their formulas beyond epa/msds requirements.

"The fungicide might be toxic to the tree?"

I would be surprised if it was. Some paints use chlorothalonil as a mold inhibitor. As you know chlorothalonil is also used as a fungicide on stone fruits. Even if a fungicide were mildly phytotoxic to the tree, the bark probably wouldn't absorb enough compound to cause a problem.

Chlorothalonil, like many insecticides is stable over a wide range of pH and will not degrade in paint.

Cool, good info, sounds like we have a mix now!

I don't know. It was just speculation on what could possible cause issues. There are number of different compounds I've seen mentioned in various literature on paints, so it can vary from product to product. In any case, it's the dose that makes the poison. I don't think the manufactures would be of much help. I imagine they would simply tell you not to use it on trees because it was not formulated for trees. Of course that don't mean anything.