leaf prob

definately not a mold ... when you water do you pour the water on top of the leaves too? It looks like salt build up from your fertilized water. Get rid of the miricle grow stick, it's not a tomato plant. You can buy a good organic fertilizer from your local grow store, cheap fertilizer causes a magnesium (salt) build-up in the soil which will start to yellow your leaves (the bottom leaf on the 3rd picture has yellowing to it)
 
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