and what is the cause of sagging leaves? solution?

so transplant from a jiffy cube to a gallon at 1 to 2 weeks? then when do I transplant to a 3/5 gallon? and I rinse the jiffy cubes with tap water, is that ok?
kennedy63 Reviewed by kennedy63 on . New to growing, general indoor questions 1. I am starting seeds in a jiffy seed starting cube, how soon should I transplant into a larger container, and when I do, what size should I transplant to? 2. Are heat lamps bad? or lights sold at home depot specifically called "Plant Lights" bad? I bought a plant light and it was blue and killed my 2 inch tall seedling in one night. any info? 3. I bought fox farms "Grow Big Liquid Plant Food for vegetative growth" when should I start feeding a new seedling with it? the package says Rating: 5