Wooden window boxes are an old standard in the industry. They are classy and beautiful, and come in many sizes and designs, with wide open options for customization. A standard wooden window box can be expected to last 3-5 years with regular care and treatment. If you are a little more of a handyman and stay on top of the box’s maintenance, then you can extend that to 7-10 years. If it's a window box made from cedar or cypress, and you stay on top of the maintenance, then you might be able to get up to 12-15 years of life out of a wood window box.
Regular maintenance includes checking the drainage each time you water to make sure it is not blocked causing the box to store excess water that can be detrimental to both the box and the plants. Checking the box inside and out for any signs of rot at the end of each season. If you find rot on one of these regular checks, then you need to remove it before it can spread. This can involve replacing an entire board or digging the rotten portion out of the affected piece, then filling it back in with bondo or other wood filler, sanding it smooth and then re-sealing with paint, stain, caulking, or clear coat. Even if you do not find rot, about every 2-3 years the box is going to start turning gray, or lose its luster requiring sanding and refinishing the box with fresh paint or stain. This regular maintenance and occasional repair can be time consuming and more trouble than the average DIYer would want to handle.
Another option for extending the lifetime of the box is a liner made of plastic, an insert that keeps the dirt and the majority of moisture from being in constant contact with the wooden box. Using a Liner in your wooden box allows you to have the beauty of the wooden box with the protection of the plastic box.
No Rot Window Box Alternatives
PVC window boxes made from composite plastics look and feel like wood and can be painted any color to match your color scheme. They are 100% bug and rot resistant and can be made in multiple configurations such as large ground planters, hanging or rail top planters, and window boxes. They are extremely versatile and will serve you and your home for a lifetime of gardening satisfaction. With over 1000 standard size and style combinations if they do not have a box to fit your needs then they can custom build it for you.