Lime sulfur shelf life

My bottles of lime-sulfur spray always precipitate white, hard flakes that settle in the bottom of the bottle a year after opening them. Unopened ones have kept several years. Is there a way to salvage the bottles that precipitate like that? Would heating it on an outdoor burner work, or is that too dangerous? At any rate, once you open a bottle, use it generously, or give the rest away, as it will be no good the next spring.

I’d heat it in a water bath and stay upwind. Stir as necessary; it’ll either go back into solution or it won’t. It’s my guess (emphasis there) that if it does redissolve it’ll work fine.

That water bath is a good idea. Thanks. Anyone else ever tried this?

Problem with a water bath is that it limits the maximum temperature your mix can reach, and you may need to go higher to get where you need to be.

In researching where to try to find more, I found the following online comment on the pet dip version by the manufacturer:

If a precipitate or crust occurs with the dip, immerse sealed container in warm water for 15 minutes and shake well before use.

So it would seem it doesn’t hurt it to separate like that. As hard as it is to find the stuff any more, I would hate to have to throw it out. There are 37 states that Peaceful Valley of CA can’t ship to, and in CA and NV one needs a commercial license to get it. Yet the pet stuff one can bath animals in. Go figure!



I tried heating the precipitated bottles of lime sulfur with no luck. Finally got rid of them.
Today I ordered some pet dip. It came in 16 oz. bottles, which if you use at the weakened strength of 2 tablespoons per gallon would give me 16 gallons of spray. That is way more than what I need, but since it doesn’t keep after the bottle has been opened, I figure I might as well spray everything I can but the apricots. That would be cherries, plums, apples, blueberries, gooseberries, currants, grapes for sure, but how about pears, filberts, Carpathian walnuts, butternuts, chestnuts, honeyberries, blackberries, raspberries, Cornelian cherries, kiwis, Schisandra? Is there any point in spraying them, especially the non-bearing ones? I use a trombone hand-pump sprayer because of steep terrain, so that’s a lot of pumping. Some items were sprayed with Kocide copper last fall, so should I also use lime sulfur this spring or is that overkill? Things seem fairly healthy, except the raspberries and tree cherries. Refresh me on what the outside temperature should be when I spray them while still dormant.


I’m surprised your bottles don’t last so long. I think my current 5-gallon jug is 5 years old. Some precipitates but there is still lots of liquid stuff left.

They will definitely go back into solution if you heat them for long enough and high enough temps, but it is a potentially dangerous proposition I have so far passed on.

on lime sulfur shelf life, 1910, the national nurseryman:

properly handled lime sulphur preparations apparently can be preserved indefinitely. Ordinary changes in temperature have little effect on them. But they are very sensitive to a number of influences. Continued exposure to air, for example, results in the development of a crust of solids of varying thickness. This is prevented by cutting off the exposure to air either by an oil covering or by immediate storage in tight closed vessels filling them completely. When the crust does develop it can be skimmed off with a fine screen and readily redissolved by heating either in water or in the concentrate itself.

in another note in the same journal, “oregon agricultural college” recommends the same 1 to 10 to 1 to 12 dilution for lime sulfur “just as buds are swelling” which is pretty neat since that’s the same ratio on the label of my orcal lime sulfur today

go ahead and ignore all the stuff in the journal about lead arsenate… but it’s great that lime sulfur is basically safe (other than for the applicator) and still effective at the same rates for over 100 years


Thanks. I guess I will try adding a bit of oil to the bottle if I have leftovers to store til the next year.