The wood you choose for your planter box depends on what you plan on growing in it.
What everybody is looking for in a wooden planter is for it to be long-lasting, with no wood rot, and attractive in appearance. So, let’s learn more about different woods and choose the right one for you.
The buzz words here are usually how attractive the wood is, how long the wood will last, and finally, its resistance to rotting.
For a planter box, durable and rot-resistant woods such as cedar, redwood, teak, cypress, or pressure-treated pine are good options. Cedar and redwood are naturally resistant, teak is durable and moisture-resistant, cypress is lightweight and rot-resistant, and pressure-treated pine is economical and treated to resist decay.
If you want your wood to last a very long time pick from Douglas fir, Cypress, and Chestnut. For buyers with an unlimited budget use Walnut, White Oak, and Black Locust wood. Teak is another expensive option that lasts really well.
When choosing your wood, remember that Cedar is a native American wood which makes it more sustainable and also Cypress. Both of these trees produce natural oils, making your planters attractive while also being resistant to insects and fungi.
Both Cedar and Cypress are also fairly lightweight if this is a consideration in constructing raised beds. See below for more information on the advantages of raised bed gardening.
What are you planning to grow?
- Decorative flowers and shrubs?
- Edible flowers and herbs?
- Vegetables and edible fruit?
Depending on your answer, read on to see what you should consider before deciding on which wood is best for your planter.
- For decorative flowers and shrubs, you don’t need to worry too much about the chemicals used to preserve the wood for your planter.
- If however, you want to eat things you have planted into it, then it’s time to think about the chemicals used to preserve that wood. The last thing you want is those chemicals in your belly.
Questions about the different trees often used in wooden planters are shown in FAQs below.
For now, let’s concentrate on how wooden planters survive for many years in outdoor conditions.
What wood treatments are used for wooden planters?
- Some planters are completely untreated and these need sealants annually so that they don’t leak water.
- Untreated wood planters can be lined to prevent leaks. This lining is also useful for keeping the wood preservative outside your soil.
- Pine is frequently pressure treated which stops rot but also causes shrinkage long-term.
- The wood from Cedar and Teak both has natural oils, which repel water naturally. Some gardeners recommend using Larch wood; this timber can be used untreated but take advice from your wood supplier on this.
- However, it should be noted that Cedar, Teak, and Larch are more expensive than Pine for example, so if your budget is tight, this should be a consideration.
How do I keep my planter box from rotting?
Wondering how will you protect your planters, like any outdoor furniture which uses wood, from rain and weather? If your planter is for decorative shrubs or non-edible plants, then this is less of an issue.
First use a commercial sealant followed by a preservative like paint or varnish, for long-lasting protection. This will help your planter to remain functional for 5 years or more.
However, if you want to grow herbs, lettuce, edible fruit or flowers, or indeed, anything that will go into your mouth, be aware that any commercial varnish you use may end up in your stomach. Makes you think again about what to coat your planter with, right?
- Use natural oils which repel water and are also not harmful to humans. Examples of these include linseed oils and hemp oil. They are not completely waterproof but water-resistant. Be aware that these two may slightly darken the color of your wood too, as they protect.
- Two coats of oil are better than one! The oil seeps in and a second coat gives even more protection. Apply after the first one has dried for a double layer of natural resistance to water.
- Beeswax is commonly used for many household activities and also on boats for its natural water-resistant qualities. Use liberally by applying with a cloth or sponge. A second coat will improve resistance and repeat annually. It is not heat resistant however and it can still be scratched.
Using any of these oils or wax means that you may need to line the inside of your planter as well. This adds extra protection from leaks.
You can purchase polythene of plastic as a liner from your hardware store – just remember to take the measurements with you. Eco-friendly gardeners prefer not to use plastic and to use landscaping fabric instead. Worms prefer this too and beneficial insects are happier with fabric too.
Can I use pressure-treated wood for a planter box?
Yes, you can, but it very much depends on what you want to plant into this box. Read on for pros and cons.
- This wood is very resistant to wood rot and also helps to keep insects at bay.
- The chemical treatment keeps it fairly weatherproof unlike natural pine, which will need a sealant in order to be used as a planter.
- Remember that pressure-treated wood has a chemical preservative. This is what helps the wood to be resistant to rot, but also insects and to make it as weatherproof as possible. If natural pine is used then it requires sealing, in order to ensure that it can stand the weather.
- Another problem with pressure-treated wood is that it shrinks. If pine is used, it is a very soft wood so it gets damaged easily when anything bumps into it.
How can I source cheap wood for raised garden beds?
Raised garden beds offer many advantages for gardeners. Basically, you are constructing an open box, whose base rests directly on the soil.
Raised beds with wooden edges are very attractive in a garden rotation plan, as they can have paths in-between. And it is very easy to assign certain plants to a different raised bed each year.
Another advantage is easy access for those with mobility issues. If you have knee issues that prevent you from bending, a raised bed is just what you need. You can sit supported in a wheelchair or on a chair while you garden. The flat top of the bed can be used to place pots, gloves seeds, and tools on the wooden edge as well as a welcome cup of tea!
Many plants appreciate the weed-free, deeper soil of a raised bed. You can space plants closer together than in a normal bed, because of the fertility of the soil and lack of competition from weeds.
Carrots grow perfectly due to the depth, the lack of stones, and they are super easy to pull out from the comfort of your chair.
When you are sourcing wood, it is a fact that everybody wants the cheapest price and the best quality wood. However, sustainability is also an issue affecting everybody nowadays.
Therefore, if you are buying new wood, then try to ensure it carries Forest Stewardship Council (FSC) certification. Remember that the best wood for sustainability is probably the wood that grows closest to you.
Get creative and recycle!
So another alternative is re-using old wood, which you can saw, chop and fashion into a stunning, raised bed area in your garden with easy access and improved crop yield.
Consider asking friends for old wood leftover, old furniture you no longer have use for, or buying offcuts from a local carpenter. Many websites provide second-hand sleepers, which make fantastic raised beds and planters.