Chemical root pruning


Does anyone have experience using Spinout, Microkote, or a DIY version on potted plants? I was thinking about giving it a try.


I have used Microkote with pawpaws. Just painted the interior of 14-inch deep Treepots.

I was very pleased with the results - it absolutely eliminated root circling and there were a lot more lateral roots off the taproot in these trees versus non-treated pots.

I didn’t have a large sample size, but it also appeared these trees had more vigor when planted in the ground.

From my experience, if your goal is to eliminate root circling in trees, Microkote totally works.


Thanks for the feedback. I plan on giving it a try. Probably the DIY version with Kocide mixed with paint because I have some bigger pots I want to use.


I just googled this kocide version and came up with this -

is that the idea or do you have some other notes?


That’s basically it. I found some info on tropical fruit forum. The link above looks like they just copy and pasted that info.


I’d be interested in using this, too.

Does it “persist” after transplanting? In other words, if I grow a tree this way and then eventually put it in the ground, will the edge of the rootball still have some of the chemical on it,and keep the roots from growing out into the native soil?


I read quite a few threads on the other forum and from what I gathered it’s not soluble and not translocated through the plant. It just kills when the root touches the paint. I’m by no means a chemistry expert though!


I don’t think so. I think rather it’s the opposite effect - you have more root tips so more surface area to “explore” the native soil.
I’m 3 years out from planting trees grown in Microkote pots and see zero issues that I can tell.’
99% of the paint stays on the pot, you might have a tiny bit come off on the root ball which you can remove.

To Travis’s point, they say the copper does not actually get taken-up by the plant.
KSU reported pawpaws showing copper toxicity symptoms when they tried a copper paint, but my trees were in the pots for a year+ and looked very happy the whole time. Maybe KSU was using higher Cu concentration or something, or longer time in the pots.


Has anyone worked out a recipe for this using kocide?


I mixed up some. I went with what I found online that the spinout had 13 oz of copper hydroxide per gal. So I just divided 13/0.46 (percent copper in Kocide)=28 oz of Kocide per gal. I thinned it out with a little water too.


Thanks Travis, I might just try that out.


I coated some pots for my pepper seedlings. It’ll be interesting to see how it works. I’m going to start them soon and not plant until late May. So they stay in the pots awhile and usually get rootbound. I tried fabric pots last year, but my problem was the roots grew into the neighboring pots because I had them crammed in a tray.

It obviously made a mess doing the painting.


What did you mix the copper with ?
Latex paint ?
Other ?


Yeah latex paint. It was some plain white I had leftover from a house project. I bought another gallon of the cheapest I could find for some more. I’ll see how that works.


You might find herbaceous/annual plants don’t respond well to the coating.
Not an absolute but just a heads up


Well I just found one paper that suggests peppers might not respond well to copper or take longer to come back. It looks like it’s been successful with other annuals and vegetables though. Maybe I won’t go all in with them just yet and trial a tray first.


Would this root-pruning paint work well on apples or pears? I am planning my grafting, and how to handle afterwards in nursery beds. I might pot everything to hold it until next fall. OHxF333, G41, G890 stocks, maybe others.