Amazing !!!!! They are still alive !!!

If you do nothing else do not give them any more miricle grow that stuff is death to MJ. They look good to start and then take a slow train to deathsville. You got the setup going good envest in some hydro nutrients, they don't cost much for how much you need.

You need good water and yours has not killed them yet. Look at the sticky at the top of page for R/O and distilled water and cal-mag plus. It will help alot.

You need a meter PPM or EC and good nutrients so you can give them what they need. The good thing with hydro is if mixed to strong you can water it down but a meter helps to know what your doing.

Lights are another thing and I will just say this. The bigger the light the bigger the buds. .

When to change light ? It's really up to you. You should have 4 sets of branches. About 8 to 12 inches. However it depends on the size you want them to be. They will double in size by harvest so if you want 4 feet you flower at 2 feet or so.

In the next stage put some good nutes and light to them .

Let's us know how it's going.