Dormant Oil Question

Perhaps the best way to get things going here is to start getting some questions and answers posted, and I have one I really do need some help with. I think Scott was hoping this site might be a little more advanced than others and that it cater to more experienced fruit growers, so I sure hope he and others will forgive me for asking what I am sure is a beginner level question. But here it is.
I have always used “Volck Oil Spray” from Ortho as my dormant oil spray. Last night I learned that my Lowes store now carries Bonide “all season spray oil” instead. Both of them list mineral oil as the only active ingredient. (Volck @ 97% and Bonide @ 98%). I really have 2 questions: 1) Is either of these 2 significantly superior to the other? Main question is:
2) Since plain Mineral Oil- they type sold in the Wal-Mart pharmacy for example- is much cheaper than the dormant oil, I am wondering if it is possible to simply USE regular mineral oil as a dormant oil? or is there something in the 2-3% “inactive” ingredients that are required to make the volck and bonide dormant oil mineral oil work properly (perhaps a sticker or emulsifier, etc). I suspect if I just pour similar amounts of mineral oil into my sprayer, it won’t mix with the water…but I don’t know.

Whew, that is ONE LONG POST just to ask 1) are Volck and Bonide dormant oils roughly equal and 2) can I use plain mineral oil as a dormant oil? Thank-you.

Hi city man,

I mentioned this on the other thread but to repeat I like newbies, having learned a lot myself trying to answer their questions. The only thing is the GW site was getting a bit out of hand with traffic, posts scroll off before I even see them. So, newbies are great but too big a crowd gets hard to handle, for me at least.

Re: oil, most mineral oils are similar, but the viscosity can differ between them so they are not exactly the same. Nearly all spray oil sold these days is mineral oil. It works fine for either dormant or in-season spraying. I have used it for dormant spraying myself, several different brands.

My feeling about dormant oil is the higher viscosity the better, as the oil will smother better and longer if its thicker. So I usually use soybean oil which tends to be a bit thicker. Golden pest spray oil and Stollers nat’ral oil are two brands I have used.


I think the above will answer some questions about substituting an oil marketed for food for one manufactured to use as a hort-oil. I believe that answer is no because whether the oil is mineral or vegetable it needs some extra processing to mix with water and spread evenly when applied.

I hope beginner questions will be welcome here, if only because they inspire me to return to the basics to make sure the foundation isn’t rotting as my brain cells diminish.

The article I provided a link for doesn’t go into much detail about how the greater refinement of oil is essential in order for it to be used on growing plants. I believe if oil takes too long to evaporate it begins to kill leaves, so you have to make sure you don’t cross the line in your desire for more smothering power.

I like the above article because it suggests that oil is not so benign as often perceived and some consideration should go into the decision of applying the stuff for the untargeted organisms that are killed in the process, including pest predators.

If you don’t have a history of mites or scale in your orchard there really is no need for oil unless it is part of your program to control certain fungus, as I think Scott uses it for. If you are using synthetic fungicides this usage would seem redundant and potentially harmful to me.


Two years ago, I had some scale on some apples, so last year I used All Seasons Dormant Spray oil in January and I had no scale last year. I sprayed it again last month as a preventative with the old adage that an ounce of prevention is worth a pound of cure. I just planted a Double Delight nectarine from Bay Laurel and the lady at Bay Laurel warned me that this variety is susceptible to leaf curl, because of its large showy flowers and recommended that I spray for it. Although I don’t have peach leaf curl in my orchard, I purchased some Liquid-Cop, which I plan on adding to the All Seasons next January, just as a preventative. I figure it can’t hurt. Have you guys ever heard of large showy flowers encouraging peach leaf curl?

Thanks, Scott, for making this newbie feel welcome! I completely understand your original comment and was in no way offended. In spite of your incredible level of knowledge, you have never, ever came over as condescending or impatient with us beginners. Besides, even though I was asking similar questions not that long ago, even I get a little weary of inquiries like, “what is the best kind of fruit tree” and “how deep should I plant my apple seed to grow my own apple tree”. ha. But I’m not far from there myself, so I can’t say much!

Anyway, thanks for the dormant oil info. One last Q. You mentioned using soybean oil. You also mentioned some brand name products, so I assume the ones you mentioned have soybean oil as the main ingredient, but I am wondering if it is possible to use regular (cooking) soybean oil as a money saver? (I think I just asked one of those dumb beginner’s questions! ) thanks.,

The cooking oils don’t have an emulsifier in it so they won’t mix into water unfortunately.

@rayrose, I don’t know why they say the flowers will encourage curl. I would wait until you get curl to spray for it.


After Scott told me in an earlier post about one of the soybean oil based sprays he used,I decided to get some soybean oil and make my own.Doing a fairly thorough local search of the major grocery stores and Asian markets,there was none to be found.
I may still get some online and try it,but after doing some more reading,it looks like one of the main ones used besides petroleum based,is cottonseed oil.This may be easier to find.
Here is a link to an article about dormant oils and some recipes.I might try the one using Castille soap. Brady

PS.After reading a few of the product labels,I found there are many that contain soybean oil,even as their only ingredient.I only assumed that Pure Vegetable Oil meant corn oil or some other. Brady


Neither have I heard the size of flowers has anything to with leaf curl. I can’t imagine it would make a difference since the fungus enters through the leaf buds to affect the leaf tissue.

Bradybb, that’s interesting and makes my question moot about could I just use soybean oil. I somehow thought it was readily available on all grocery shelves beside canola, peanut, vegetable, etc. Now that you mention it, I never actually looked for it. So much for that money saving idea!

That business about big, flowery trees making peach curl more likely is very concerning to me. I just now bought a double jewel zaiger peach which would fit that “big flowers” criteria. Peach leaf curl is the one (and almost only) malady I’ve never had in my little orchard, and thoughts of it coming in due to one new tree is very troubling. But I trust the judgment of those who say there is no correlation, so I suppose I don’t have to worry about it! THanks all.

Soybean oil is much more available than I thought.I just didn’t read the product label’s ingredients enough.
I agree also with Scott and Olpea,that the flowers shouldn’t be a factor with the disease.It isn’t called Peach LEAF Curl for nothing.I have a Nectarine that was infected last year and the flowers looked fine. Brady

thanks bradybb. but it sounds like without an emulsifier I can’t use it anyway. Oh well.

From what little I’ve read,it sounds like liquid dish soap acts as an emulsifier.It’d be pretty easy to make a small batch,using something like a glass jar and see if the soap keeps the oil and water from separating.Brady

If you are spraying on green, growing tissue I would test any home made formulations and wait a couple days before applying to a whole tree. Oil can be devastating to growing tissue- at least mineral oil can.

That’s a wise approach.I’d like to stay away from putting petroleum products on plants.The most common available manufactured oils seem to based on it though. Brady

I tried a little experiment and put about a cup of water,1 teaspoon of soybean oil and 1/2 teaspoon of liquid dish soap in a glass jar.After shaking and then letting it settle for about an hour,it was then gently swirled and the film from the water’s surface moved down.Under magnification I could see very small bubbles that contained oil,that filled the entire volume of the water.So it looks like the soap did help to emulsify the oil.It stayed this way for at least a minute and was easily brought to the same condition with light agitation. Brady

When I made a batch of Neem Oil spray, I used Dr Bronner’s Pure Castille soap as an emulsifier to keep it as natural as possible as I am unsure about using dish soap on my plants. It worked well. But I would test it out on a small portion nonetheless.

I sprayed sulfur on my dormant trees about a week ago. I had Nufilm in the mix so the sulfur is sticking to the trees real good now. I can actually see sulphur on the trees. I need to spray oil to control pear psylla soon. But worried about spraying oil when I can see a layer of sulfur on the trees. What should I do (other than hosing it off)? If I spray before buds break will it be ok?
Pear isn’t at bud break. Plum, apricot in bloom and peach just about to break. Appreciate your thoughts, comments.

After I read Scott’s use of soybean oil a couple years ago, I decided to use kitchen canola oil rather than petroleum-based dormant spray. I mixed it with some old copper powder, too, Bonide I think it was, but not sure. Bad idea. The oil separated, the copper powder didn’t dissolve and sunk to the bottom, then the sprayer failed, whether due to that or not I do not know. I ended up missing the spray window entirely waiting for a new sprayer to arrive. Not blaming anyone but myself, but from now on I will stick with tried and true, plus fresh chemicals.

I’m not sure how it might affect the Copper,but the addition of a little dish soap could help blend the Soybean oil into an

You can spray sulphur and oil together before the leaves are out. I hit my pears last weekend. Note lime sulfur is better for dormant spraying, that is what I use.

Hey one thing I learned not to do is lime sulfur plus Nufilm plus copper… it made a mess in the tank. I think the nufilm was the problem I have done lime sulfur and copper before without problem.

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