Steven,
Did your paint mix with castor oil work in detering voles?
Where did you buy castor oil? Was your mix 1:1:1 paint, water, castor oil? If it worksped, I may as well paint all at once.
Maybe someone will find this helpful. I have whitewashed my trees with lime whitewash about a week ago. Ordered it online from Lancaster Limeworks. 1 gal prediluted whitewash was about $30 and will probably last me 5 years.
I am not sure how effective it is against rodents… It will wash off the trunks eventually.
6 Likes
I read somewhere to use only flat interior latex but can’t remember why.
If I remember correctly, you can use any interior paint as long as it’s light colour that can reflect the sunray. Using interior paint is because it doesn’t have UV protect additives added in. This is in my memory so far, others may chime in
1 Like
I was focusing on flat vs semi gloss or gloss. The article I read said use flat only.
1 Like
If anyone claimed use flat paint only, I must point out that the rest of the world do not even use paint(they use lime, mud mixtures…), and the trees still grow as good as the trees are painted in Flat white paint.
1 Like
Wouldn’t the concern with a higher gloss paint be that it might prevent the tree from breathing properly (I’m not sure that’s the right way of putting it but I think people will get what I mean)? So the point about using flat latex paint isn’t that you couldn’t use something like lime, whitewash, etc., but that you wouldn’t want to use something that would create a more impermeable barrier?
2 Likes
Flat latex versus glossier latex i think would create the same physical barrier…both are latex that will create a film with, I would think, the same permeability.
I would think the sheen difference only affects the surface of the cured paint.
Notice I said “think” a lot 
1 Like
Similarly high “think” level on my end. But checking it out a little, it looks like flat latex paint is significantly more permeable than semigloss (due to lower binder-to-pigment ratios). Not sure exactly how this is measured, but something like five times as permeable according to this site:
https://www.dulux.ca/diy/tips-tricks/common-problems/filler-shows-through-the-paint-(4)
In fact, semi-gloss latex appears to be significantly less permeable than flat alkyd (oil) paint, though significantly more permeable than semi-gloss alkyd:
2 mil polyethylene (medium density) 0.4
Epoxy-polyamide (gloss) 0.14
Alkyd semigloss 0.57
Latex semigloss 4.98
Alkyd flat 19.9
Latex flat 27.0
For reference, a rating under 1.0 indicates that the paint forms a vapor barrier.
I don’t know whether semi-gloss latex paint is impermeable enough to create a problem for the tree, but it seems like there’s a pretty good argument for going with flat latex.
6 Likes
Wow that’s awesome info.
Yeah I was thinking this permeability question should be answerable.
Thanks for the research.
Now I wish I hadn’t used semi gloss!
Remember, the paint has to be mixed with water 1:1, so how this will affect the permeability?
1 Like
My first paining tree trunks were 4-5 years ago. I think I did it undiluted. No damage to the trees that I could see.
So, yesterday, I did another round of painting. I felt 1:1 water/paint was too diluted. So, I ended up 70% paint 30% water.
Flat, white, latex paint.
5 Likes
Like JinMa said the higher gloss paints are less gas permeable.
The same goes for outdoor wood paint. The higher gloss paints have more binders. Those binders give it a gloss effect. But also have the largest effect on water and gas permeability. So higher gloss paints tend to be more weather proof (all else being equal)
Mud, clay, lime etc are quite breathable. Interior latex is also quite breathable.
The special versions for walls you want to clean (kitchen, staircase halway/ spots where people touch the wal with dirty hands etc)
Have more binder. So you can scrub them with water, without scrubbing of the paint. This also makes em less breathable.
If the less breathable paint becomes a problem probably depends on many factors. Diluting it thinner might help. brand etc might make a difference. Probably tree age/species matters to.
Just safest easiest and usualy cheapest to use the flat or lime based interior latex. (cheaper is usualy better, since they use more lime. Since lime is so cheap)
1 Like
Glidden gripper undiluted has worked fine for me…but I don’t have the time/desire to mix with water (or drywall compound like John at Fedco), so I just slap it on. I doubt it has to be an exact science especially if a thicker paste made by mixing with drywall compound is acceptable. We just touch up when/where needed but it’s not often.
Just curious, Have you ever actually painted any tree or you just told us what you have found out from Internet?
if painted a few trees i topworked. to avoid sunburn.
if been/spoken to someone, who paints their trunks who told me he did that to avoid winter damage. (the sun could heat 1 side of the trunk, the difference in temperature in winter would crack the wood according to him)
if done that myself on my own tree’s a few years ago. Did not bother the next year, and haven’t noticed a difference.
If painted a bunch of dubble grafted interstems last year. Not for sunburn reasons, but because i was planting them out in a heatwave. And was curious if the paint would make a difference in % of take. In the end i saw no significant difference in the just parafilm and parafilm + interior paint group. Although admitently it was a small sample group. (20 ish)
I had a small “feeling” the less light from the paint gave me a little more callous on those i “checked on” could have been coincidence, and it was callous outside so probably did not contrubute to the graft taking)
You can stil see the leftover paint here,
I do have less experiance than some/most around here. Since im still reletivly new to fruit tree growing.
This means that virtually everything if done. I first searched on the internet. If not been growing tree’s pre internet age. Im not sure, but i think i wasen’t born till after the internet.
Although i have not run a comparison on high glos vs glos vs flat paints. I thought the mechanisem (increased amount of low gas permeability binder for more gloss) was something worthwhile to add.
If i have 0% practical experiance (ie never done it myself) i mention that in my reply 
when in doubt always feel free to ask me for proof/explenation or more information
2 Likes
I’ve noticed that you are very good at searching for info from the internet and summarize your research in a concise manner. That is skillful.
It would be nice to let readers know where you get your info from (your sources) as some people may want to look into it further. Also, as you know, many sources on the internet is questionable. Some experienced growers here may be able to point that out if necessary.
Not everyone like to do research. You have done a good job in helping members here. Like any good research, citing sources and give credit where credit is due is a nice thing to do.
1 Like
Thanks for the compliment?
Hard to cite sources from memory
Most of my reply’s are from memory, and unles i mention “i don’t have any experiance” in it. I have actualy done the things.
I do however usualy first research and look up information. Until i think i understand the underlying mechanisem. With a lot of things there is no “1 way that always works” it’s usualy determining which way works best in what specific situation. “Understanding” the underlying mechanisem helps a lot with this.
Than i “practise” and do the things myself.
Explaining underlying mechanisem even though i have experiance.
I belive however just saying “i did this, and it seemed to work” is not always that helpful. And can somtimes give people low sucses. Since their situation might differ vastly from yours. So even though it worked for “me”, it is no garantee that it would work for some-one else.
To me this could be summerised by
“sharing experiance vs sharing knowladge”
you seem to suggest (although i could mis-interprete) that when i see a question, i start googeling and then type a respone. Without having any real world experiance. This is simply not the case.
Im not just researching other peoples questions.
I did however had a lot of the same questions over the past years. Looked for information and “awnsers” and started experimenting.
Citing sources and giving credit
When i can easily find a source or if i had to look it up to be sure if i remembered corectly i post that source in my reply.
Some are hard to find back though. And typing a reply “explaining” the underlying mechanisem already takes a lot of time. Looking up all “origional” sources. Than checking if your giving credit to all the right people (and not just people who got the information from some-one else) becomes incredibly tedious and takes a long time.
It’s a forum, not a scientific journal
I think you should expect people to cite all sources and credits in a post in the guides or reference section of the forum.
But your expecting to much from people to do all that extra work for a reply on a forum.
In the end this is a forum, not a scientific journal. The person asking the question should have some responsibility to verify or compare advise. Or take the risk and “trust” it, and see what happens.
I have even written a topic, trying to help people to find information themselfs. Or to help them find information to verify if given advise is “good”
Accuracy of information on the internet.
You make a verry good point, not all things on the internet are true. And it is hard to judge the accuracy of somthing without seeing the source that origionaly listed the information.
I have writte a reply in another topic about this here.
In the end the forum works in part due to multiple people “checking” others advise. And speaking up if they disagree or adding their own contribution.
2 Likes
That’s great research, now go back and find out how permeability affects the health of a tree in regards to painting trunks. It stands to reason that you want a tree to be able to have wounds dry out, but I’m pretty sure that the point of suberin is to reduce permeablity.
From wiki, “Suberin is found in the phellem layer of the periderm (or cork). This is outermost layer of the bark. The cells in this layer are dead and abundant in suberin, preventing water loss from the tissues below.”
The leaves certainly need access to the atmosphere, but it seems that trunks may be OK without it. Otherwise university guidelines probably would be more specific about what paint to use given how often it is used by commercial growers in southern areas to prevent sunburn.
My hunch is that If trunks are young and green they have chlorophyll and may benefit from permeability. The chlorophyll has to be serving a purpose and it can’t function without gas exchange.
2 Likes
it’s not a university source.
but it seems even the trunk “breathes”
I also notice that water non pearmeable but gas permeable grafting tape (like parafilm M), leaves the bark nice. But non gas pearmeably tape can leave bark black and discoloured. Tree’s seem to be fine. but the black bark worries me. If this would also happen with really old bark, i have no idea.
You could experiment and paint the whole trunk with a high glos outdoor paint. But im not willing to risk a whole mature tree to find out if the more expensive paint is oky to use. Ill just stick to the low binder cheap stuff.