Here’s what you need to know about creating a DIY wooden container planter.
Selecting Wood for DIY Planters
Wooden planters don’t have as long of a lifespan as plastic, clay, or concrete containers. Eventually they will start to rot from holding damp soil and being exposed to the elements. Plus, the nails and any other metal hardware used to make them can start to rust and corrode. However, wooden boxes can last for many years if they are made from the right kind of wood and cared for properly. Here are some good types of wood to use, as they are fairly resistant to rot, insect damage, and more:
CedarRedwoodCypressTeak
While you can also use scrap wood to build a planter, think carefully before using pressure-treated lumber. Some older pressure-treated lumber is preserved with arsenic, which you don’t want to use for edible plants. It will be stamped with a CCA (Chromated Copper Arsenate) label. Although newer pressure-treated lumber should not contain arsenic, it still has chemicals to preserve it. So if you’ll be using any pressure-treated lumber, you might want to reserve your containers for ornamental plants only. Moreover, never use creosote-soaked railroad ties for any planter, regardless of whether it will contain edible or ornamental plants. This oily preservative contains hundreds of chemicals that can cause many adverse health effects.
Preserving Wooden Containers
If you’ll be growing plants in your wooden container that are strictly ornamental—not for eating—then you can apply a chemical sealer to the planter to extend its life. Apply it to both the inside and outside surfaces of the planter. However, if you plan to eat your plants, avoid conventional wood sealers because they usually contain unhealthy chemicals that can be released into the potting soil and absorbed by the plant roots. Fortunately, there are some wood preservative treatments that are safer than chemical wood sealers for containers that will grow edibles:
Paint-on products that contain acypetacs (a common brand name is Cuprinol) are considered safer than chemical sealers. But the wood will need to be retreated more often than with chemical sealers.Water-based preservatives based on boron salts are considered safe; they are generally applied in paint or gel form. However, they don’t bond well with wood and require frequent reapplication.Made from flaxseed, linseed oil has good wood preservative properties but takes quite a long time to dry. Avoid products that are mixed with solvents, such as mineral spirits. And be aware that linseed oil is flammable before it dries.
How to Build DIY Planters
When starting with an existing wooden container, there are just a few steps to get it ready for plants.
Tips for Growing in Wooden Containers
Once you’ve created your wooden planter, here are some tips to help ensure its longevity, as well as the success of your plants.
Elevate the planter on pot feet or small blocks of scrap wood if it will be sitting on a wooden deck or patio surface. This will prevent trapped moisture from affecting the underlying surface and create space for the planter to drain. At the end of the growing season, empty the container of the plants and soil. Store it in a dry place for the winter. Apply a fresh treatment of your preferred sealer at least annually. The soil in smaller wooden planters will dry out fairly quickly. So be sure to monitor them closely, and water the plants as necessary. Large wooden planters can be very heavy. Consider using a lightweight fill material at the bottom if your plants won’t take up the full space with their roots. Use a commercial potting mix, rather than ordinary garden soil, in your planter. Potting mix has the nutrients that your plants need. Plus, garden soil generally doesn’t have as good of drainage, which can rot your wooden planter and impact plant health.
