I water my roses with Epsom salts dissolved in water. It provides magnesium and sulphur, I just read. There are pros and cons -- the cons mainly being don't use too much or that would be detrimental.

Perhaps the tomatoes benefit from epsom salt just as roses do.

Rose

A tablespoon sprinkled in the hole won't hurt. You can also dissolve it in a gallon of water and pour it in the plant hole or use it to water the plant.

That said, as is with all fertilizers or additives, it is only worthwhile if the plant needs it.

I used Epson salt last year as advised by someone on the GW and I had the best and the most tomatoes I've ever had.I will use epson salt from now on.
moonphase