Love triangles? Not you! Raised garden bed design with triangles? Absolutely! You like the look of a spaceship design or a Star of David with composite plastic timbers for edging. But when you're planning your garden landscape edging, how much soil do you need? When you do your raised garden planning, remember that in a closed garden space with garden edging, you need less soil--though the soil you do use has to be high quality.
Generally speaking, for raised gardens with triangle landscape edging, you need 60 to 80 cubic feet of soil--just enough to fill the triangles to the top. For a single triangular raised garden bed design with a second tier, plan 18 to 20 cubic feet of soil. Don't forget that with your soil you need organic compost, so don't fill the space between the garden landscape edging with soil.
You don't like love triangles...but your plants in your Star of David raised garden bed design seem to be carrying on a romantic intrigue. Wisteria Lane, anyone?