Following are screen shots from the Wisconsin PBS video about sack planters on the parking lot of a Salvation Army pantry. I have added further explanation and comments about this highly productive and inexpensive way to grow vegetables in the city.
A layer of gravel is poured into the bottom of the sack to create a base. I would add a layer of pourous nursery fabric or plastic screening to prevent soil from seeping into the gravel base. This retains air space between the pieces of gravel.
Position a can (with the top and bottom removed) in the middle of the sack on top of the gravel base. This will act as a mold or form for a gravel column that will go from the bottom to the top of the sack. Add soil until level with the top of the can mold.
An alternate method is to create a center core for the gravel column by using a piece of window screen material rolled into a round column shape to form the core. The screen retainer would rise from the gravel base to the top of the planter in one piece.
What is not quite clear in the video is that she lifts the can out of the soil at the bottom of the sack. The gravel stays on the bottom of the planter. Now reposition the can on top of the first soil/gravel layer, fill with soil around it, add gravel and repeat this procedure until reaching the top of the sack.
The planter is complete. Here you can see the gravel column that facilitates flow of water from top to bottom throughout the sack planter. Equally important are the pore spaces between the pieces of gravel that provide all important oxygen to the root system.
I have other ideas on using this basic system to make vertical planters like these even more productive and durable. Stay tuned.
Most helpful instructions. Thank you.
Now, how does one water this sack planter?
Posted by: H2 | February 07, 2012 at 04:05 PM
It seems like we have rehearsed this. You ask the good questions about things that I fail to cover. ;-)
Top watering with a can or hose (use a soil probe to check the soil moisture first). http://bit.ly/xkYlDK
Top watering! Who would believe I said that? Judging by the quality of the plants I see in these sack planters, the center "oxygen column" makes the difference. See the Send a Cow videos in today's post. http://bit.ly/AgTw9p
Posted by: Greenscaper | February 08, 2012 at 10:12 AM
The kids in today's post show it all. Thanks for the answers, Bob...
Posted by: H2 | February 08, 2012 at 06:04 PM
My pleasure Heidi. I look forward to getting past my medical issues to be able to work more with children of all ages. We can learn much from kids who have not yet learned to be spin doctors and bull-throwers.
Posted by: Greenscaper | February 09, 2012 at 04:17 PM