Urban Garden Oasis Design Planter Help

[AndyFellows]

Hi Everyone!

Looking for some help with my garden design. I've attached a picture of what were looking to do. This is in the middle of an industrial estate to provide a space people can get away from all the concrete and grey. I have to get this started this month but have a few design questions to resolve before I can.

The total size is about 17m*13m

Key question and expense will be the planters and im struggling to decide what material to make these from. The intention was treated kiln dried wood but the prices are so high just now. These planters are 90cm high and wide all joined together for watering purposes. Are there practical affordable alternatives other than concrete?

 

[Marck]

Greetings, welcome to the Forums.

Would it be possible for you to attach your file as an image?

 

[DirtMechanic]

Sheet tin or a osb wood product called smart panel will stretch a dollar

 

[AndyFellows]

Thanks nice to be here, theres a photo below:

These are big external planters and the skin for them would need to be able to hold a heavy weight of soil, small trees and bushes, cant see sheet tin or OSB being strong enough and OSB wouldn't last long?

 

[DirtMechanic]

I suspect you are looking at structural walls tied together internally, braced to each other. I suspect that it is zoned land and you will find a connection to a structural wall construction permit need which involves an engineer. Every 90 cm horizontally you will be supporting at least 1 metric ton of earth if not 2 when wet especially, so call it 3. If that wall pushed over you would not have time to escape the speed at which that pressure would spring the mousetrap over on you. Since you will not be digging supports in, a self reinforcing box design laid upon the earth seems likely.

 

[AndyFellows]

Thanks for your response. These are free standing planters sitting on concrete, not tied into walls. Can be a little lower at 70cm if 90cm is too onerous. At the moment we are looking at timber frame 3*2 squares every 1m with 38mm thick scaffold boards to clad it with plant liner internally. Looking for other options since this is timber and labour intensive.

 

[DirtMechanic]

Thanks for your response. These are free standing planters sitting on concrete, not tied into walls. Can be a little lower at 70cm if 90cm is too onerous. At the moment we are looking at timber frame 3*2 squares every 1m with 38mm thick scaffold boards to clad it with plant liner internally. Looking for other options since this is timber and labour intensive.

I do not know how you can beat poured concrete. You might want to ask a concrete supplier about the name of the mix you are looking for because I doubt it has to be high strength though it probably will have some type of wire or thin rebar in it. Protip: here rebar diameter is measured in 1\8" inch increments of thickness. Thus a #4 rebar has 4\8" thickness or is 1\2" thick. Like wise for #5 rebar. you may be able to use just remesh wire like they make tomato cages with or a #2 or #3 rebar and those thinner metals are far more economical. You may need it just around the top, or maybe just the middle and top. The remesh would go in like a fence in the middle of course. The rest is sand and gravel with just enough portland to hold it together. Personally I would add some lime to help it not break from shrinkage but those locals know the needs of the environment where I could not speculate. I would think a steel remesh reinforced thickness would be far thinner than you suspect. Thus it would use far less material than you would suspect. The concrete contractors have reusable metal forms these days so they are in a position to barely charge for what would have been a great deal of form wood.

 

[Marck]

Consider using concrete 'cinder' blocks. In the U.S. they are available in different colors and shapes. There must be similar materials in the U.K. They can be joined with mortar, filled with concrete, and/or reinforced with rebar. The also take stain and paint well if another color is desired. I've built low raised breads, only 20 cm tall, and left the hollow blocks open at the top and filled with soil. These pockets make great cubbyhole planters for herbs, succulents, bulbs and other small plants.