I'm starting with a highland grow chamber for heliamphora and orchids. I know, I know, it's not Australian plants! Hey, what can I say, sometimes diversity is a good thing... My basement, with the furnace off but dehumidifier on stays at 63-64°f and about 53% humidity, I will monitor this as we get into the colder months and I finally let the wife turn the furnace on. I may also adjust the dehumidifier to increase ambient humidity slightly.
Below are the pictures and steps to the first part of the project, the rough build.
Part 1 - Rough build
I started by taking my lumber to school and having one of the woods classes cut it to the approximate dimensions I mention below. I build the table top/tray bottom out of convenience. The table top/tray bottom is made out of 2x4 lumber with the supports spaced every 20". The total size is 5ft by 3ft. The legs are made from 4x4 treated lumber since they will be in contact with the floor. They were cut to 32". I'm 6'3" so you can cut these shorter if you wanted. The sides of the tray will be made from 2x6 lumber and cut to 36". The front and back of the tray will be 2x6 lumber cut to 63". Build the platform and place is too down on floor. Place legs in corner of 2x4 frame and secure with 4" screws. It is best to pre-drill the 2x4s to prevent splitting and cracking. Try and make sure the cuts are as straight as possible and the legs as perpendicular to the table as possible. Make sure legs are parallel to each other. I may add some 2x4 reinforcement runners in the future, but I don't anticipate this setup weighing enough to be a concern. Tada! A table! But wait, there's more... Assemble the tray sides using 3.5" screws to make a box. You may find it easier to leave the back side off until the rest is secured if you don't have a perfectly square top... (Student work is free, but not always accurate, haha) The tray sides are 2x6 which means the board is 5.5" wide. I measured down approximately 1 3/8" on each side of the table and made a mark. Take a 4" screw and install it on your 4 marks, two on each side of the table. You can now place your tray sides on these screws to hold it while you attach the tray to the table. Using 3.5" screws attach the tray sides to the table. Make sure the screws are going into the 2x4 frame and not the 1/2" plywood! I would also recommend pre-drilling the holes to prevent cracking. The inside measurements of the tray are 3ft x 5ft x ~4in. Pick your favorite flavor of pond liner and place in the tray. I happen to get this piece free from a co-worker who had it laying around. Hopefully it doesn't have any holes...