Please watch your feeding them during winter time. This is their rest time and they don't need fertilizer at all in their native soils. I did this because I have a problem with root rot at this time. I keep them too cold. Too costly for me to keep them at 75 or so. The sulfur lowers the ph so the fungus can't grow and they do live in that range in nature and I look at phosphorous more like a mineral supplement than a fertilizer which encourages strong root growth. Well at least that's the way I look at it that makes the most sense to me.
Hope it helps.
Stush
