Question about changing soil

Ok here we go. I have a friend who is growing and asked me this question and I have no idea what to tell him. He has 3 seeds from bag (good shit too...:thumbsup:) that he is growing in 10" pots with Miracle Gro moisture control soil. He is worried about the soil having enough nutes to last through flowering. He says he is gonna veg for about 4 weeks before flowering but wants to replace the soil with the same type when it comes time to flower. Would this be a good idea for him to do? I know that every transplant is gonna give the plants some trauma but if done carefully would this be a good idea? Basically using the soil hes got and then replacing it with new about a week before flowering. I have seen a couple of MG moisture control grows and the plants look fucking beautiful during veg, nice happy plants, but never thought about flowering. The bag says its good for 3 months but naturally after watering the nutrient content is going to diminish. He does not have any kind of meters or testers and just wants to grow this way for this grow until he can get the correct shit to check everything. Stinky feel free to chime in here hun..i know you are the head gardenologist (like that word huh?...:thumbsup:) here amongst many others:)Anyone for some input here? Thanks all who reply.:thumbsup:

When you transplant you don't 'change' the soil; you are simply putting the entire rootball with all the old soil still attached in a larger pot with fresh soil.
The roots need to be able to keep growing as the plant grows larger.
Personally I distrust Miracle Grow soils because they are peat-based and contain fertilizers that you willl have a hard time getting the feeding schedule right because of. Oooh that was awful grammar, lol, but i'm too baked to go back and change it.
The Miracle Grow organic is not that bad if you add some extra perlite to it, but a quality potting soil is a wonderful thing.
You still will be giving liquid fertilizer during bloom. Flowering cannabis feeds more aggressively than the ferts in that soil will be able to provide for, and at the wrong ratios of NPK. The amount of Nitrogen in pre-ferted soils isn't great for flowering; it can lead to leafy growth and not as much bud.

Thank you Stinky..:thumbsup: Have you ever tried the moisture control soil? What do you suggest as far as liquid ferts during bloom? knowing that moisture control is being used.

I've never used a moisture control soil but for bloom I'd go with a mostly-organic fert such as pure blend pro bloom that contains plenty of humic acids. These organic acids are the good stuff in compost, and will help prevent the dreaded interactions between the soil ferts and the liquid ferts that can lead to lock-outs later on. Bonus, it's pretty cheap as ferts go.

Thanks Stinky. I had actually planned on using the MG myself when I do decide to grow but I think I will go with the organic like you suggested. Is the pure blend pro bloom something that home depot would have or walmart, or is it specialty order stuff?

You can only get botanicare stuff at a grow shop. While you're there, check out the better soils they have. MG is kind of a 'eh... this is all they have' option.