The growth stimulator will not give it what it needs to grow. End of week two I start 1/4-1/2 strngth ferts. Or the start of the third set of branches. which ever comes first. Thats when the plant starts needing those ferts. Just start the ferts low and work your way up to the "recommended amount". Always be watchful if using cheaper types of fert. such as Miracle grow or schultz or something along those lines. Those tend to be a little too strong from what I've seen from people using it.