Andrea and I had run out of room on our terrace with our potted garden, so we decided to go all in with a raised garden. See our other post for the construction of the boxes and arbors. When it came time to plan, we had to line the boxes with plastic to prevent chemicals from the pressure treated wood from getting into the soil. We covered the bottom with felt to act as a weed barrier.
This garden is going to take about 10 yards of soil mixture to fill. That's 20,000 lbs! 120 bags of garden soil from Lowes! 50 bags of perlite! And a bunch of compost that we will generate over time.
Since we are using pressure treated wood, we had to line the boxes with 6 mil plastic to prevent the chemicals from getting to the soil. Note, we wouldn't have to do this if we had used cedar or some other naturally moisture resistant wood. The felt paper in the bottom of the box acts as a weed barrier.