Gardening costs money.
You spend some part of this money buying planter boxes. But it would be nice if they last for a long time. So how long will your planter boxes last? Is there some way to know this?
Wood planter boxes last from 3 to 30 years depending on the wood and treatment. Metal planter boxes last from 20 to 40 years. Plastic planter boxes may last up to 50 years. And concrete planter boxes last 50 to 100 years when maintained.
In this post, I’ll help you understand how long your planter boxes will last. I’ll also give you steps on how to increase the life of your planter boxes. And tips on selecting the right planter box based on your needs.
How long do wood planter boxes last?
Wood planter boxes can last 3 to 30 years, depending on the type of wood used to build them. Untreated lumber can last 3 to 5 years before it rots.
There are wood types that are resistant to rot, such as redwood, cedar that can last 15-30 years in ideal conditions. Some more examples of such wood are cypress, white oak, teak, mahogany, and black locust.
I think the best wood for planter box is cedar wood. It is durable and has a natural resistance to rot and insect damage. The natural oil in the wood acts as a preservative and improves the lifespan of the planter box.
Pressure-treated wood can last 30-40 years, but I don’t recommend those because the treatment could involve toxic materials. This is not a good option, especially if you’re going to grow vegetables in the planter box.
The wooden planter box could get expensive depending on the type of wood that has been used to create it.
How long do plastic planter boxes last?
Cheap plastic planter boxes could last 1-5 years as they may break down because of the heat and cold. Recycled good-quality plastic can last up to 50 years without problems.
Plastic planter boxes are one of the cheaper options compared with materials such as metal, wood, or fiberglass.
How long do metal planter boxes last?
Metal planters can last 20-40 years depending on the type of metal being used. Steel could rust faster than galvanized metal. Aluminum planter boxes could last several decades before they get some oxidation problems.
Metal planters can be expensive compared to wood or plastic planter boxes. But they will last a long time and that should offset the cost.
How long do fiberglass planter boxes last?
A fiberglass planter can last for 10-50 years, depending on the material used and the maintenance of the planter. It’s one of the most durable and lightweight materials you can find for a planter box.
It can be expensive compared to a planter box made from plastic or wood.
How long do concrete planter boxes last?
Concrete planter boxes can last for 50-100 years without problems. They will need some maintenance, but that should be minimal.
Stone planter boxes are another option if you’re looking for something that will last almost a lifetime with minimal maintenance.
You will need to spend a little more money on such stone or concrete planters compared to other materials like wood, plastic, or fiberglass.
How to make planter boxes last longer?
The life of the planter box will depend on the material used to build it. But you can take certain measures that would help improve the durability of the planter box.
1. Line the planter box
You can use material such as plastic, newspaper, cardboard, landscape fabric, or wire mesh to add a layer at the bottom of the planter box.
Lining the planter box can help prevent pests and diseases from reaching your planter box, especially when made with wood.
Plastic liners can keep moisture away from the planter box only if you set it up correctly. Ensure the liner sticks to the planter box.
If there is any gap between the liner and the bottom of the planter box, it will cause moisture buildup and speed up rotting.
I asked fellow gardeners which methods they prefer to improve the life of their planter box. Below are the results. 35% think it’s a good idea to ensure good drainage so the planter box can last longer. 30% also prefer to line the planter box.
2. Paint the planter box
Use paint on the inside and outside of the planter box to increase life. This is especially useful for a wood or metal planter box that rots or rusts because of moisture.
The paint can help reduce the chances of water reaching the wood or metal. Use a waterproof and/or rustproof paint and one that would seal the planter.
It’s best to use an organic, non-toxic paint, especially when you’re growing vegetables in the planter box.
You can also use an organic wood sealer that will coat the wood and make it waterproof. It will also protect it from pest problems. Some examples of such sealers are linseed oil, hemp oil, SoySeal, and Soapstone sealer.
Check out the section below where I show you how to apply the linseed oil solution to waterproof the wood planter box.
3. Clean the planter box
It’s good to maintain the planter box at least before every growing season and maybe the end of the growing season. Cleaning the planter box will help improve its life.
You can remove the potting soil and liner before the growing season every year. Clean the planter box using a solution of 1 part bleach or vinegar mixed with 9 parts water.
Let it stay in the planter box for 1 hour and then rinse the planter box well with water. Keep it outdoors so it can dry before you reuse the planter box. This will help remove any pests or diseases in the planter box.
This is also the best time to check the planter box for any cracks, discolorations, leakage that you may need to fix. It’s also good to check whether the liner has deteriorated and needs a change.
If you do this before the growing season, you can add fresh potting soil and start growing plants. If you do this at the end of the growing season, you can store the planter box in your basement or garage until the next growing season.
4. Move the planter box indoors
It may be beneficial to move the planter box indoors to improve the life. You can do this at the end of the growing season before winter starts.
This may only be possible if you’re using small planter boxes that are easy to move around. Or planter boxes that you have placed on moving trays.
Moving the planter box to your garage or basement will protect it from the cold and problems such as cracks that can result. This is especially a problem with wood, metal, and concrete planters.
You may need to move the planter box indoors during the growing season as well. This could happen if there’s going to be a heat wave or cold spell during the spring/summer.
The extreme change in weather can damage the planter box made from wood or metal that can expand and contract.
5. Use a thick planter box
This is especially useful when your planter box is made from wood. The thicker the planks used to make the planter box, the longer it will last. The thick planks will not bend or crack fast.
The wide planks will also help as there will be less seam between them. This reduces the amount of moisture that can stay in such seams after watering. So the planks will take much longer to break down due to rot.
You may have to spend a little more money to get a good-quality and thick planter box. But it will be worth the price as it will last a lot longer than cheap, thin ones.
6. Raise the planter box above ground
One of the common problems with wood planter boxes is the bottom rots first. This is because the bottom is in contact with the soil or grass all the time.
When you water the planter box, the draining water will be absorbed by the soil that remains in contact with the bottom of the planter.
So the best way to avoid this problem is to raise the planter box above ground so it does not touch the soil.
You could get a planter box that is placed on a stand. Or you could use bricks/concrete blocks to raise the planter box above ground. It’s sufficient to raise the planter a couple of inches above the ground.
Make sure that even after the planter box is raised above the ground, it has good drainage. The drainage holes at the bottom should not be blocked because of the material placed below it.
7. Ensure good drainage in the planter box
One of the common reasons for damage to the planter box is moisture collecting on the sides or bottom. It’s best to provide good drainage in the planter box so the excess water does not collect.
Use good potting soil in the planter box rather than garden soil. The potting soil is light and has the right texture to retain sufficient moisture but drain out the excess.
Garden soil could contain clay that will cause the moisture to remain in the planter box for a lot longer than required.
Your planter box should have sufficient drainage holes at the bottom. Make sure that the drainage holes are of the right size and water is drainage properly. Otherwise, you may need to drill the drainage holes yourself.
You can add material such as coco coir, dried leaves, milk jugs, terracotta pot pieces at the bottom of the planter box as filler. Such material helps create pockets that encourage good drainage from the soil.
How to choose a planter box that lasts long?
If you’re planning to buy a planter box for your garden, you can pick one that lasts long depending on certain criteria.
If you want a planter box that would last a very long time, you can choose one made with stone, concrete, or metal. These materials could last 50-100 years when maintained.
The drawback would be they are heavy and you won’t be able to move them around easily. They make sense to use in your outdoor gardens at a permanent spot.
If you want something light yet durable, you could choose a fiberglass or plastic planter box.
The least durable would be a wood planter box that could last 3-15 years, depending on the type of wood it is made of.
Cost of the material
The price of the planter box could be the deciding factor for some. Materials like concrete, stone, fiberglass, and metal can be expensive.
A planter box made from plastic or wood would be a cheaper option, depending on the type of material used.
Climate of your location
If you have a dry climate, you could use a wood planter box for several years without problems.
But if the climate is humid, the wood planter box will rot a lot faster. It makes sense to pick another option like plastic or fiberglass instead.
If you’re using the planter box in a location that gets too hot or too cold, a stone or concrete planter is not suitable, as it will conduct the heat or cold to the plants.
But if the climate conditions are moderate, these materials will work fine for your planter box. They would retain the heat for the plants longer during the cold season.
Plants you want to grow
The type of plants you want to grow would also decide your planter box. A wood planter box works well for plants that need less frequent watering. So the wood will not rot quickly.
If you’re growing vegetable plants or plants that need frequent watering, it’s best to use plastic, fiberglass, or galvanized planter boxes that can handle such moisture without problems.
Availability of the planter box
There could be planter boxes made from plastic, wood, and metal that are easily available in your location.
And planter boxes made from fiberglass, stone, or concrete that are harder to find.
Or you could find wood planter boxes made from untreated lumber but not from maple, teak, or mahogany.
So your choice could get limited by the type of planters you can buy from the garden centers, nurseries, or hardware stores available in your location.
How to waterproof a wood planter box?
Waterproofing a wood planter box can help increase its life as it keeps the moisture away from the wood for a longer time and prevents rotting.
It will protect the planter from the moisture because of watering and the rain if you keep the planter outdoors.
A simple option is to use a mixture of linseed oil and mineral spirit in a 50:50 ratio to create a waterproof sealer.
The linseed oil helps waterproof the wood, while the mineral spirit will help thin the linseed oil and make it easier to apply.
Mix it in a cup and you can apply the solution to the planter box wood with the help of a paintbrush. Apply it inside and outside of the planter box.
Give it a good coat so all areas are covered. The wood should soak up the solution as you apply it.
Once the finish is applied, keep the planter box outdoors so it can dry out before use. This can take 1-2 days depending on the weather and how warm it is.