Building a Raised/Elevated Garden Bed for Senior Center
I was asked to make raised garden beds at my local senior center for my boy scout eagle project. Unfortunately I don't know anything about gardening, so I'm hoping I can get some help here.
They want 2 beds 8 to 10 feet long. And they requested that the beds are at least thigh height so that the seniors don't have to bend down so much. A raised garden bed that is that tall seems like it would cost a lot of money to fill with good soil though, would it be more reasonable to make an elevated garden bed?
Could I just make an elevated box out of pressure treated lumber put it on 3' posts and fill it with dirt? I'm a little worried that a box that is actually off the ground won't hold enough water though. It's going to be maintained by the seniors there and I don't want it to need constant watering or all the plants in it to die.
If I did make an elevated garden bed what would I use for the bottom? Would it be like a mesh screen?
Would you go with an elevated or raised garden bed?
If you think a raised garden bed is the way to go, what do I fill it with? Can I just use like a fill dirt for the base?
Thanks! Any other tips are greatly appreciated as well, I don't know what I'm doing :P