Hey Al, Thanks for checking in. In response... 1) I am looking to water more to allow the media to not always be saturated and also for the nutrients to not build up and become toxic. I would like to be able to keep the nutrient levels consistent and allow the plants to dry up a bit. I am growing tomatoes and heard flavor is better when this occurs. 2) I am planning on two tomato plant rotations in the greenhouse...could do one, but refreshing the tom plants might be a good idea and would allow me to rotate varieties and work the seasons more efficiently. All input is truly appreciated, Al. Thank you.

Grizzman, I don't think I am overthinking it. I think you are thinking this problem through with a regular 5 gallon bucket in mind. A regular 5 gallon bucket for paint is highly unlikely to collapse like tbaleno's is collapsing under the described circumstances. Instead, it would cause a vacuum and not let the water out. I've not seen Home Depot's buckets, but Menard's (another big box store) buckets are practically translucent because they are so thin. I wouldn't be surprised if the manufacturer for both companies is the same. With flimsy enough walls, the walls will collapse before air entering the tube moves far enough. Once the walls are collapsed the pressure is stabilized as the air in the bucket is compressed. Unless the air coming in the tube is forced air (unlikely), then it won't make it up the tube if the bucket has begun collapsing. At least not enough to stop further collapse the next watering. As the collapse starts it will put positive pressure on the tube and not allow air to enter from there. You are absolutely right that a larger tube will speed up stabilization, but it first speeds up destabilization. It is then just a matter of whether the bucket walls can withstand the initial destabilization or not. Just judging from what was originally written, that the bucket is collapsing already, the walls are very thin and I have those Menard's buckets in mind. Maybe I'm incorrect and tbaleno has thicker buckets than Menards provides. Another thing that could be contributing to the collapse is the length of the tube. If it is too long AND the wall of the bucket is too thin, then that will also cause collapse before air can travel up the tube. Personally, I would be inclined to go with both, a sturdier bucket and a wider diameter tube.

TRT when you are setting up your lights check if you have a Taps Plastic near you and get mirrored plastic. Rip a 45 degree slot in a 2x4 at a length that will fit on the box and insert the plastic about 6-8 in high and reflect the light back and under your plants you will be surprised how much more light your plant gets and they can be moved as needed.

My understanding is you get more or less the same productivity from a container whether you plant 1 plant or 2. The 2 plants will compete and limit each other's output, so you don't get any more total tomatoes. But one advantage to 2 plants is you get twice as many early season tomatoes. That's because the first truss of tomatoes arrives at about the same time on each plant, before the plants have gotten big enough to crowd each other out. Also, if one plant gets a disease, you may be able to remove it and save the other plant. Having said that, I grow 2 cherries in a 15 gal pot, not a 5 gal pot, so your mileage may vary.