After cutting mine down and looking at roots. The bottom of soil was moldy or bud rot. On both plants. The reason for this was, no air getting to bottom to dry up the water. My first 2 grows I had wire fencing under it and everything went fine and roots looked great after harvest. This time I just used a couple of 2x2 about 8" long, thought I moved them around enough so they wasn't always in the same spot. It didn't work. If I was you I would transplant or get something under them so air flow can get to the bottom of pot. Transplant might delay growth for about a week, but if your roots are moldy now, your in for a beating.
When ya think about it, just common sense if no air gets to the bottom, water will not dry up. I will still stick to my watering routine, because the first 2 grows were great. I will just have to put the fencing material on the bottom from now on. The bottom I made was just a peice of plywood, whatever size you think your plants will fit on. i used a 4x4' peice of plywood to cover bottom of box then cut plastic to cover entire peice of plywood Then run 1x2 or 2x2 about 6" apart all the way across plywood, then attach 1/4" square fencing or chicken wire. The 1/4' is stronger, so I used it instead of chicken wire. Attach to the 2x2's. That should leave you about 2" of space from the fencing to the plywood. sit plant on top, water will hit plastic and drain. I have a 2x4 just laying on one end of box for a slant. Excess water drains to the front, where I keep a towel to soak it up.
Might be able to look at roots and just put back in same pot. Read some on transplanting before you do anything. There is a good way to hold the plant when turned upside down, you tube will show alot. Get them up off them pans though, my earlier post saud to use 2x2 to keep off the floor. Didn't work, using fencing did. If you do decide just to look at the roots. Read about how they are suppose to look. I remember reading something about root lock or nuet lock. Something about if pot was to small for the plant, the roots will look a certain way. That way when you check your roots out, you will be able to tell if it should be transplanted.
Ton of work, but I would transplant right away and put something under them for air flow. Might delay growth a few days, but 5 gal pots might have problems. Might have difference in quanity too. I used these potato sacks, not sure on gal. size I figure around 20. Both grows avg. about 3 to 3 1/2 oz. off each plant dry. On these last 2 I got 67 grams on one and 75 off the other. I also threw away the bottom potion of both. It was where the majority of visible mold was and I'm getting spoiled, I thought it was to much work for about a half oz. of popcorn buds that were prone to get mold. The rest of the plant in cure now and no sign of mold. Haven't smoked any yet, It's a clone of what I'm already smoking. Should be just as good,,,lol GL
Make sure you follow through on posting results, curious to see if I can get away with a smaller pot. Fox farm is expensive, when you use almost a bag per plant.
Thought I would add this since I have had trouble with all 3 of my grows. Check leaves on plant about every 2 or 3 days for mites or mold. If you find it right away, it's easy to control.