You have a couple things happening here. First, the soil appears to be getting too dry. You do want to thoroughly soak the soil then allow it to dry out about 3/4 then rewater. You don't want to let the soil dry out to the point that the roots dry out as well. You want the outer layers to get dry while the inner layers, where the roots live, to stay just moist. This is something that every grower has to learn through trial and error if they don't have an experienced person present to show this.
Second, it is critical for the plants to have "fresh air". This means the air within the grow space (your tent) must be sucked out with a centrifugal fan and exhausted outside of the space where it could be pulled back in. Then fresh air from outside the grow space needs to be allowed to be pulled into the tent to replenish the heated and CO2 depleted air that is being pulled out. If you have your grow in the garage, that is good as it will allow you to do just what you need. In your grow space, you want fresh air that is around 75f all the time as that is ideal for the plants.
However if you are in a cold climate or hot climate, you will need to adjust the outside air to approximate temps before it gets pulled into the actual grow space. This should be easy enough for you do as you can use the garage as the adjustment zone for the air to be pulled in and acclimated to serve the plants. This means that You set your exhaust fan to pull air out of the tent and exhaust it out of the garage, either through the same window as the AC is or through another location that will lead out of the garage.
Then there needs to be some open ports somewhere in the garage that connects to outside so that as the air is removed from the tent, it will pull air into the tent through the passive holes at the bottom (just like a vacuum cleaner hose), and the air that is pulled into the tent causes air to be pulled into the garage from outside. You probably already have something like this set up for the AC if it is running. This cycling of fresh in and old air out can be accomplished with the one exhaust fan without issues.
Now that is part off the problem that I can see with your plants. Another problem appears to be a lack of magnesium as the margins of the leaves are slightly lighter green to yellow and the leaves are curling up like a taco shell. These are classic symptoms of magnesium deficiency, which is not at all unusual for new growers (and some older growers) to experience. I believe the issue is as much a lack of moisture as it is a lack of magnesium. But as you are in FFOF, I am assuming that you have only watered them and haven't done any kind of feeding.
I would recommend that you get some dolomite lime and sprinkle about 3Tbsp (I am guessing at the size of your containers as 3gal) onto the soil and work it into the soil so that when you water them, it will dissolve into the soil. The next thing you are going to need to do is look for some nutrients for going forward. That soil will only feed the plants so long before it becomes extinguished. That is usually around 5-8weeks I think, depending on how well the plants grow and use up the available nutrients.
At this point you need to decide if you want to go organic or synthetic with feeding. I believe the FFOF is set to allow you to go either direction. Each way has its own set of challenges. The easiest 2 ways to go are (in my opinion) Espoma organic fertilizers that come in pelletized fform that you can directly feed on top of the soil and water in each time you water. These have both the essential nutrients needed and all of the microbes needed to maintain the organic biozone in the soil.
Or if you want to go with synthetic nutrients, the 3part General Hydroponics Flora series is quite easy to work with and gives solid results. With the synthetic nutrients, you will have to maintain the pH of the solution that you feed with. This will require you to purchase a TDS meter and a pH meter so that you can get proper amounts for the plants.
Either way I recommend that you do some serious reading in our sections that cover that information.