Do Wooden Planters Rot? 10 Ways to Stop Planters Rotting

By   | Last Updated :   October 29, 2021 | Filed In :   DIY & How To

Are you thinking of adding a wooden planter box to your outdoor collection? Wooden planters are quite popular but how can you prevent the wood from rotting?

Here’s what you need to know to protect wooden planters from rotting.

wood planter box rot

Will a wooden planter rot?

Wooden planter boxes aren’t always made from the most rot-resistant wood. This means that no matter how well you care for the box, it will eventually rot.

Fortunately, there are quite a few things you can do to improve the durability of your wooden planter.

How to stop wooden planters from rotting

Preventing rot in your wooden planters may sound quite daunting. Fortunately, it’s quite simple. Here are a few methods you can try to improve the durability of your wooden planter box:

1. Wood preservative

Wood preservatives are always a great option for preventing rot. You can combine this treatment with some of the other methods to make the whole process even more successful.

For this method to work you will need a wood preservative of your choice and a paintbrush. Apply the preservative as per instructions and you’re good to go.

Wood preservatives tend to have similar ingredients due to the worldwide regulations put in place. For this reason, which preservative you choose shouldn’t matter too much.

For the best results, treat the wood with a fungicidal wash before painting on the preservative. This will prevent mould and other spores from growing on your wood underneath the coating of preservatives.

Wood preservative is quite effective in preventing mould and algae from growing on your wood, but preservative isn’t the best at killing already established spores.

staining cedar planter box

Credit: Shutterstock

2. Plastic liners

Plastic liners inside your wooden planters will also help to minimise contact with moisture and keep wooden planters from rotting. Liners are usually used in combination with wood preservatives.

Liners are usually glued or more commonly stapled in place inside the wooden planter. You’ll have to make sure that there are still drainage holes by puncturing the liner directly over the existing drainage holes in the wooden planter.

Liners help with preventing evaporation in planters with too much airflow through them and keep the soil inside the planter. This is quite important in wooden planters that resemble a picket fence.

Plastic liners are usually made from thick plastic sheeting. This makes them strong enough to be manoeuvred into place without breaking. It also makes them more durable than thinner plastic.

3. Plastic inner containers

Plastic containers are very useful in wooden planters made from poor quality wood or those without drainage holes. The container can be removed from the planter before watering. This means that your planter won’t be coming into contact with moisture at all.

You can combine this method with preservatives and plastic liners to make sure the wood is even better protected. There are a variety of inner containers so you can choose one that fits perfectly inside your wooden planter.

Garden planter plastic liners

Garden planter plastic liners by DeepStream Designs

4. Planter stands

Another way to protect wooden planters from rot is by placing them on planter stands. Planter stands elevate the box and in the process prevent it from standing in the pooling water underneath it as water drains.

Planters that stand in water are more likely to rot. This is also true for planters that are in contact with a lot of moisture due to standing on a surface that doesn’t allow airflow underneath the planter.

Planter stands simply take all of these factors out of the equation by lifting the planter and allowing airflow underneath it.

5. Liquid sealants

If you don’t want to struggle with plant liners, you can also consider liquid sealants. Liquid sealants are made from silicone that can be sprayed onto the planter box.

You will need to properly prepare the surface before applying these sealants otherwise they won’t stick. Fortunately, this method is quite effective at preserving wood if applied correctly.

You can also still combine it with some of the other methods like the inner container to make your method of preservation even more effective.

6. Varnish

Varnish is also a very effective method of preserving wood. You have a choice for a clear varnish or stained one. Varnish not only preserves the wood against water damage but also brings out the natural beauty of the wood and preserves the colour.

Varnish can either be sprayed or painted on. Just make sure to pretreat the wood with a fungicide to remove any spores before applying the varnish. This way you can prevent any mould growth underneath the coat of varnish that can lead to wood rot.

7. Fibreglass

Fibreglass can also be used to seal planters, but it’s not the most preferred method. Fibreglass can be quite messy to work with. There is also a health risk while working with this substance.

If you choose to go with this method, make sure you have all the appropriate safety equipment like gloves, glasses and a mask.

8. Waterproof paint

If you don’t want your planter to keep its natural wooden look, then you can paint it with waterproof paint. Make sure to treat the wood with a fungicide before applying the paint, however. You don’t want any nasty spores that will ruin the wood and your paint job.

You can paint the planter box any way you like as long as you make sure that the paint you are using is waterproof. You will also need to paint both the inside and the outside of the planter for this method to be successful.

Do Wooden Planters Rot? 10 Ways to Stop Planters Rotting 1

Painting your planter box will help it last longer. Image credit: @casaredesign1

9. Placement

If you did everything you can for the inside of your planter, the next step is to protect the outside. You can do this by either using wood preservative, varnish, waterproof paint or planter stands.

Where you place your planter will also play a role. If you want the wood to last without messing with the outside of the planter, make sure to place your planter in an area that doesn’t get rained on or wet for any reason.

By keeping your planter away from external moisture, you can keep the wood looking good for longer.

10. Type of wood

If you have a choice, make sure to choose a wooden planter made from wood that is naturally rot-resistant. These planters can be made from woods such as cedar, ipe, oak and redwood.

Of these woods, cedar and redwood are most often used in planters. They are naturally warp and rot resistant which means that your planter won’t be bent out of shape if it accidentally gets a bit wet from watering your plants.

Final thoughts

If you follow one of the methods above or even employ a combination of them, your wooden planter boxes are sure to last quite a while longer. If you do yearly touch-ups and maintenance on your planters, you can even get more than 10 years out of your planter. A lot of it depends on the kind of wood you’ll be using, however, so make sure to choose wisely.

Happy planting!


Do I need to seal a wooden planter box?

Sealing a wooden planter will prevent the wood from rotting. This means that you’ll be able to use your planter for much longer.

What is the best way to protect a wooden planter?

The best way to line a wooden planter is by using a liquid sealant. These sealants sit flush with the wood and prevent any moisture from getting through them. Plastic liners have the disadvantage of not being attached to the wood. This means that moisture can get in underneath the plastic causing the wood to rot.

How do you fill a wooden planter box?

The best way to fill a wooden planter is in layers. The layer all the way at the bottom of the planter should allow for drainage. This means filling the bottom with something like rocks, gravel, broken pottery or even plastic bottles. On top of this layer, you’ll add mesh or something similar to separate the soil from the drainage layer. On top of the mesh add the potting soil of your choice. Now your planter is ready to be planted in.

You might also like: How to waterproof a wooden planter box

Do wooden planters rot 10 ways to stop planters rotting-min

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