Sulfur for overwintering
 

The time of the year is approaching, summer dormant plants are starting to wake up and winter dormant plants are starting to slow down and begin their dormancy.

Some will go in the fridge, and I have a pretty crowded fridge this year after some impulse purchases last spring, so I thought of giving the plants a little extra protection by sprinkling sulfur, a tip I’ve read from dahlia and carnivorous plants growers.

Does anyone do that to overwinter their orchids? Whether it is on catasetum, or orchid tubers. Sulfur is a great fungicide but I don’t hear that many orchid growers mentioning it, so it makes me wonder if there are phytotoxicity or desiccation risks when applied to orchids.

I overwintered cypripediums in the crisper drawer of a fridge. Bare root in plastic bags, with no other treatments.

My dad used a sulfur evaporator in the begonia greenhouse during winter months, in order to limit mildew attacks. We did not need to do this in the orchid greenhouses.

What does it do? Is it just fungicide?

Sulfur is a fungicide. The most effective preprations have the largest surface area per volume - fine powders, often sold as flowers of sulfur.