so happy I found a Craigslist post for these. They say they are BPA free and #2 recycle food grade. $15. I figure I can cut them in half and get two large planters out of each. Just can't find healthy food grade planting pots anywhere so this seems like a great answer. If I knew someone who owns a restaurant I could probably get plenty recycled. This is the next best thing I think. They are blue barrels which the web says are industry standard for transporting food products. Can be painted on outside with spray paint suitable for plastic or screen them with lattice to make more decorative. If cut horizontally can then be put on wooden frame and use as raised planter. Or cut the other direction to make two deep planters for larger plants.

You will also probably see these 4 letters imprinted just under the triangle "HDPE" High-density polyethylene www.hdpe.com

Same material that's used to line a landfill, used for Bamboo root barrier, and a array of other gardening products.

When I cut them in half, I make them into Sub-Irrigated Planters. The reservoirs are used to hold water only, no ballast rocks needed. The reservoir top is made from 10mm sign material called Coroplast. Drill 4 holes thru it and insert micro-fiber polyester material for the wicks, this way water can travel upward farther up the soil column. The reservoir is filled using a 3/4" PVC pipe ending just above the soil line and ending just below the reservoirs top.

By drilling 8 to 16 holes thru the sidewalls you can do vertical gardening at the same time, then the top can be planted with more plants.

Caution: Do not let the cut containers that are empty, sit in the sun, or the cut edges will start to curl, I've even had them get almost square looking viewed from the top.

The following photos are similar to a 55 gal barrel cut in half, they are made from the same material HDPE, but are black in color. Each is able to grow 8 vertical planting holes and anywhere from 1 or more plants in the top, depending on the mature size's of the plants






The SIP tub planter, pictured above has 15 salad greens planted in it.

@thunderbear thanks very much for all the great info!

I have this one out at the back of my house away from public gaze . The colour is a little loud but I never bothered to paint it . I modified it to work on the Earthbox type wicking system. It holds quite a bit of water and only needs topping up every few weeks. You can see the overflow holes near the bottom. This year it's going to be planted with early potatoes, Home Guard variety.