Following the successful placement of 120 square feet of black plastic, on level ground according to the link below, I have a rougher terrain to cover which is uneven. What materials are used to weigh down a space, when it’s uneven? I think I have a flexible light old hose for the perimeter which could bend to the contours of the ground, but it might need some weight. I also have to carefull not to tear the plastic.
The remaining 10×11 plastic will drop easily onto an 8×15 square feet of the bed, inside a larger space, with a space cushion to tend to some perimeter flowers on two sides, and a side with a garage and pathway on the other sides.
The challenges of wind blowing up the edges, and a bit of sloping down, with some interest in what rain might do to the first space of 120 square feet, and a need to rest from the extreme heat, make me consider delaying with imminent rain forecast in west end toronto.
Your flexible, light-weight hose sounds like a good idea for the perimeter of the black plastic but as you mention it may need more weight in some areas. Various items can be used for this purpose including stones, bricks, wooden planks or landscape/garden staples available at garden centres and hardware stores.
Good luck with your project.