Proper drainage is the unsung hero of successful urban gardening. The arrangement of holes in your planter box bottom is crucial for plant health. The best method is not just about the number of holes, but their strategic placement.
For standard rectangular or square boxes, space holes evenly in a grid pattern, approximately 6 to 8 inches apart. For smaller boxes, a minimum of 3-5 holes is essential. Always place a hole at each corner to prevent water from pooling there. The holes should be between 1/4 to 1/2 inch in diameter—large enough to allow water flow but small enough to prevent significant soil loss.
Before adding soil, cover the holes with a permeable landscape fabric or a layer of small rocks or broken pottery shards. This simple step keeps the soil in while letting water escape freely. This strategic arrangement ensures excess water can drain from the entire root zone, preventing soggy soil conditions that lead to root rot and fungal diseases, giving your urban plants the foundation they need to thrive.