The new tomato plants were out today, and I couldn't resist, thinking surely, I had some large planters at my apartment. You guessed it, no planters, but I do have a cat. He's particular about the cat sand he uses, and fortunately for me, I had several of the "plastic" bags in the recycle bins. They're wide and fairly tall. When filled with soil and a plant is about the same size and a large planter. It looks kinda funky, but hey, the cat wasn't going to use them, and they was free.
I really love your idea! This is one very green way to garden! About the way they look. You can always wrap a recycled solid colored plastic bag around them!
Several years back, I also posted a tip about not using planters. Just the bag of soil! You lay the bag of potting soil on it's side then cut an X in what's now the top & poke some drainage holes around the sides & towards the bottom of the bag. Now plant your tomato or whatever, right into the bag filled with the soil. NO planter needed! When you water, place the spout of a watering can or the hose right into the X-shaped hole.