This contest specifically requires everything to fit in a 50cm cube, so I thought a lot about how to configure my plants vs. my lights. I was on the fence about putting plants in the middle surrounded by lights or lights in the middle surrounding the plants. Lights in the middle won out because this gives me more surface area on which to grow plants when they're young. In either configuration the leaves will crowd each other at high density, but I'd rather this happen when the plants are more grown and solve it by harvesting overlapping leaves vs. when the plants are young and some are possibly too crowded to grow at all. And, I really like the idea of a crazy bright LED ball in the middle:)

I want my grow chamber to:

Keep the roots in nutrients/water/air at the right ratios Provide the right amount of light to the leaves Make it easier to control things plants care about. At a minimum, we want to make sure temperature is OK, the roots don't dry out, and the lights stay on

Here's a useful overview for size etc. requirements for Outredgeous Lettuce.

I experimented with Cardboard Core Composite Fabrication, and I'm still excited by it. But, my results were pretty messy (I think my resin might have been too cold) and I gave myself multiple headaches. So, I'll wait until it's warmer and experiment more with this outside:) I've included a couple photos of what it looked like in case you're curious. If you experiment with this, please do so carefully and share your results!

What I ended up going with was part of a 27-gallon HDX storage tote with a piece of plywood + garbage bag liner as a divider + barrier to reduce the size to only 19 inches in length (we're a bit shorter on width and height). You can leave this out or do a smaller, partial-height divider if you're not specifically trying to use this grow chamber for this contest; with a smaller isolated chamber, you can place all the fans electronics etc. inside for a neater look and easy stacking (be careful to properly isolate electronics from water / fog).

The plants themselves live in part of a 12-gallon HDX storage tote. I used a pull saw + utility blade to cut it down to ~8.5 inches in height, and I used 2 of the 4 top corners as legs, attaching them with 3 screws each. The legs create room below the tote for the water reservoir + atomizer.

After cutting the 12-gallon tote to height, make holes in it for your net pots + foam collars using a 2" hole drill. Err on the side of more grow sites: you can always leave them plugged up to grow fewer.

You'll finish the grow chamber by lining the interior of the12-gallon tote and the lid of the 27-gallon tote with aluminum foil. Spray on adhesive and then put the foil against it, duller side facing the adhesive. The foil prevents us from wasting as much light: it reflects a lot of what hits it back to the plants. Poke holes with a pen and then use your fingers to tear / fold the foil away from the 2" openings, and you're done building your grow chamber!