Small Space Garden Project

I started a garden project for my small space, to have a vegetable garden on my condo balcony. The garden is a “grow bag” garden based on Larry Hall’s Kiddie Pool Grow Bag Garden System. The idea is that porous grow bags are filled with potting mix and sit in 2″ of water in a basin. The original design uses reusable Walmart shopping bags in a kiddie pool with 2″ of water. There’s a hole cut out at 2″ up the side of the basin to allow overfill water to drain out in case it rains. To keep mosquitoes from breeding in the water, you can fill the basin up 3″ deep with pea-sized pebbles. The water only comes up 2″ so the water is below the top of the pea gravel.

My take on the design was to build a rectangular basin to hold 2 rows of grow bags, and to put it on my condo balcony, maximizing my usable space. I would line the basin with a thick plastic pond liner to hold the water. I also wanted a stand for a rain barrel which would supply water to the basin. There would be a float valve (like you have in your toilet tank) in the basin to regulate the flow of water into the basin automatically. If the water level falls below 2″, the float valve would allow water to flow into the basin then shut-off when the water level reaches 2″.

This is the space where I want the grow bag garden to go.
This is my original design I drew in SketchUp, a 3D CAD program. I designed it originally to use (5) 20-gallon grow bags.
Here is the lumber I bought at Home Depot to do the job. I used a total of (2) 2×6, (11) 2×4, and (1) 4×4
I cut all the lumber first, then I started building the frame of the grow bag box.
I spaced the floor decking of the box with just screws to make a gap, in case any water got through the pond liner, I wanted it to drip away.
The grow bag box and rain barrel stand are done!. Next step: pond liner.
I decided at some point that I would rather have (11) Walmart reusable shopping bags as grow bags, instead of (5) 20-gallon bags. I also decided I needed casters (wheels) so I could move this box around and clean underneath it.
Here is an “exploded” and “cut away” view of my design, showing all the components from the box, to the liner, to the pea gravel, to the Walmart grow bags.
I cut the 7′ x 10′ pond liner to fit and doubled over the edges and stapled it to the sides.
The grow bag planter box is done! The casters were a HUGE improvement, a really necessary idea. You can see the pond liner is doubled-over on the edges and stapled to the box.
I filled up (9) Walmart reusable shopping bags with homemade potting mix, and folded over the edges to keep the handles out of the way. I was surprised, each bag holds about (7) gallons!
The pea pebbles are in the grow bag box now surrounding the grow bags and the water level is below the pebbles. Take that, mosquitoes! No standing water for you! You can see the sides of the bags are soaked because they’re wicking the water out of the bottom of the box.
All done! All (11) grow bags are in the box with the pea pebbles. Now, I just have to plant seeds and wait for vegetables to grow!

Make sure you also check out my Garden Progress page to see how the vegetables are doing!