Winter Grow!

If your adding in a form of nitrogen to the medium that needs breaking down then yes bacteria can help. I 2nd LABS or lactic acid bacteria. however if your feeding a liquid nutrient regime then it is already available and does not need any breaking down and the addition of bacteria won't do much for how the plant absorbs the N, it might help in other ways in reducing shock or some other symbiotic relationship in the medium but for absorbing N not much. Less water till the plants get bigger, rot issue will start to from if its to wet and the medium will grow some nasty microbes if its left unchecked to long. Good Luck!

Dry back is always good. As long as it's not to the point of wilt. Dry back encourages roots to explore for water and food and the result is a more robust root system. It's similar in concept to air prune. It's normal for a plant to have some die back of it's roots. It encourages lateral root branching and exploratory growth. Not only that, but dry soil holds way more oxygen than wet soil, and that's why cannabis flourishes in soil on the dry side rather than always soaked. I've always been a hydroponic water culture grower, but I've recently decided to try coco coir. People always say coco is hydroponic, but it's really not in my opinion. DWC water pumps don't clog up with perlite and coconut fibers.... I know it's inert, but still. Hydroponic is roots suspended in water to me, or in rock wool or hydroton, or lava rock. Basically something that requires constant water flow. Coco is the same idea as rock wool, but rock wool won't clog a water pump so fuck off lol When my plants are full size in 3 gal fabric pots i have a consistent watering/feed schedule on my last crop. I fed on Monday. Each pot got 2 liters of nutrient solution. Tuesday, Wednesday, no water or food. Thursday's Each pot got 2 liters of water with calmag. Friday, Saturday, Sunday, no food or water. Then repeat the weekly routine. Worked well. Only prob i had was a salt build up in the soil which caused a plant burn around week 3 or 4 of flower which is why i recommend flushing between week 2 and 3 even if your plants seem fine. It's a preventative strategy which i think is a insurance policy against toxic salt build up and resulting plant burn resulting in reduced yield. You topped that plant pretty early. I usually top at the 5th or 6th node. Looks like she'll be ok though.