Install Moisture Barrier (Pond Liner) and Drainage Layer (Base Stone)

What happens here

A durable pond liner is meticulously installed along the entire inner surface of the planter that abuts the house. This liner acts as an impermeable membrane, creating a critical waterproof barrier that prevents any water from the soil or irrigation from seeping directly into the house's foundation or sub-structure. Beneath the pond liner and the future soil layer, a layer of well-draining base stone (gravel) is introduced. This gravel layer forms a crucial drainage system, allowing excess water to quickly filter away, preventing waterlogging and further reducing moisture exposure to the house. The presenter notes the benefit of "well-draining sand" in Michigan, implying that this drainage layer will effectively direct water away from the building.

Goal: Prevent moisture from reaching the house foundation and ensure proper drainage for the planter.