How do I stop the bottom of a wooden planter box from rotting?

I used to watch my beautiful wooden planter boxes slowly surrender to rot, their bottoms turning soft and dark after just one season. It felt like a betrayal—I gave them soil, water, and sunshine, and they repaid me with decay. But then I realized: the problem wasn’t the wood; it was how I treated it. So I rolled up my sleeves and became the doctor my planter boxes needed.

First, I raised them off the ground. I placed a few small plastic risers or even flat stones under each box to let air circulate beneath. This simple trick stops moisture from being trapped against the wood after rain or watering. Next, I drilled more drainage holes than I thought necessary—about four to six half-inch holes across the bottom. Water needs an escape route, not a pool party in my planter.

Then came the liner. I lined the entire inside with a heavy-duty landscape fabric, but I made sure it didn’t block the drainage holes. The fabric lets water through while keeping soil out, preventing that wet, rotting sludge from hugging the wood. For extra stubbornness, I added a one-inch layer of gravel or pebbles at the very bottom before adding soil. This creates a buffer zone so the wood never sits in damp mud.

Finally, I sealed the wood—but only the outside and the bottom edges, not the inside where soil contact happens. I used a non-toxic waterproof sealant designed for planter boxes, applying two coats and letting them dry thoroughly. Now my planter boxes stand tall and proud, their bottoms firm and dry after months of rain and watering. The secret? Listen to your wood. Treat it with care, give it an exit for water, and it will thank you with years of loyal service. Your planter bottom doesn’t have to rot. It just needs a little love and a lot of drainage.