We have a TSC farm store and I will ask for potassium sulfate, but it would be in the granulated form, would it not? Miracle Grow is all over the place, in every store including the Canadian Tire, but we do not get a great variety of stuff, not like you do in the States. The place I checked is "the nursery" for Greater Toronto for fancy stuff and they did not have anything special like you mentioned, but they had some potassium product, not sure if it was sulfate in a 2 kg box. Need to look into it again. Then there is the problem of the correct dosage. The tomato food is water soluble, it has trace elements and the potassium number is very high. Do not know what chemical form though. I think it is a Miracle Grow product. Many times I feel like a poor cousin when I look at the stuff available in the States. It is probably the matter of "supply and demand", roughly thirty million of people spread over the second largest country in the world (although at least half of them live in Southern Ontario), as opposed to your three hundred millions plus. Thank you for all your help especially since I am a "tender bulb ignoramus". Bea in Ontario, zone 5