Welcome to the group.
Do not worry. The group can give several good tips that will help to get the plants back to a healthy green.
I do not know for sure how many plants you have going but it looks like two tall ones. The reason the plants have so many leaves that are turning yellow is that the plant is already larger than the soil and soil micro-organism can handle.
My first suggestion is to transplant to a larger pot using a decent soil. Those pots look like a standard 1 or 1 1/2 gallon size and they should've been in a 3 gallon about 3-4 weeks ago. And, a 5 gallon pot would have been better.
Phytoplankton also brought up the lights. Definitely think about ways to raise and lower the lights or raise the plants up closer to the lights as they grow. I can see sections of the plant where the nodes are closer together which is better than the sections where the nodes are several inches or more apart.
Occasionally I end up with a couple of plants that are too tall and I will end up topping them and then transplanting into the final size pot 2 or 3 weeks before putting them into the flowering tent. I would pick a spot about half way up and cut there and then transplant. Topping them just before transplanting will make the transplanting process a bit easier. You could try rooting the portion that is cut off if you want and maybe end up with a clone.
Good point. A suggestion is to pick a line of fertilizers you will feel comfortable with and start to us that. At first treat the plants as if they are showing a deficiency of both.
I agree with Phytoplankton even though a fellow Michigander says otherwise
. He does live on the other side of the state and all that. But then they have some excellent craft beer breweries over there which is a positive
.
Picking up on some of basics first will tell you if going down the rabbit hole in a soil type of grow will be helpful or not. Many growers end up with good quantity and quality just using the basics. Learning the basics first help understand and use the more technical aspects of growing.
@NewbieRick, tell us a bit more about the soil mix you are currently using, whether you already have a line of fertilizers picked out, and do you have a watering schedule or a way of telling when it is time to water.