Outdoor To Indoor Hydro

I recently transplanted two 2 month old outdoor plants (purple urkle) into my power grower. They seem to be doing fine. The new growth is nice and green. the only problem is that the lower leaves on both plants seem to be turning yellow. i keep my ph leveled out with lemon juice and aim for 5.5-6.5 at all times. im using General hydroponics flora series nutes.

One more quick question. How did going from soil to hydro work. i just tried it because i didnt want to wait on seedlings and some how they have continued to grow for about 5 days . How is this Possible?

If its the older growth going yellow, its probably natural and don't worry about it. Is the plant still in soil? or a new hydro medium? a transplant from outdoors in should be fine as long as if you plan on changing medium, gently shake off as much of the soil as possible and water in well to the new medium. Give it a week and she should be back in full swing.