7 Best Waterproof Liners For Planter Boxes (How to Use)

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

Do you have a metal or a wooden planter box that needs some protection against moisture? You’ll be surprised to see how many options you have when it comes to protecting your planter boxes. Waterproof planter box liners come in many forms. Here’s what you need to know to improve the durability of your planter boxes.


Garden planter plastic liners

Garden planter plastic liners by DeepStream Designs

What is a waterproof liner?

Waterproof liners are mostly made from plastic. They come in many forms from plastic containers to plain old plastic sheeting. In some cases, you can also get spray-on liners.

Liners are meant to protect your box from the constant moisture of potting soil. They are the best way to keep your planter from rotting prematurely if you’re using wood or rusting away in the case of metal. If used correctly, you should be able to get many more years out of your planter.


Types of waterproof liner for planter boxes

If you want to line your planter, you’re going to have to choose a liner first. If you’re a bit confused, consider one of the following options:

1. Plastic pots

Plastic pots are quite convenient. They can be placed inside other containers such as your wooden planter. This way you can remove the whole container when you need to water your plant and simply return it to the planter box afterwards. Your planter box will never be in contact with water if done correctly making it last a very long time.

Stallion 10cm x 27cm x 13cm Brown Rectangle Rattan Planter Case Box

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2. Plastic sheeting

If you want a more permanent liner, then plastic sheeting is a good option. Simply staple or glue it onto the inside of your planter box. Just remember to create drainage holes in the plastic. Most plants will rot and die if left to stand in water for too long.

plastic liner

Prolong the life of a wooden planter with plastic lining. Image credit: London Stone

3. Resin

It is possible to waterproof planter boxes by lining them with a cloth dipped in resin. As the resin dries, it will create a sealed layer that will protect your planter from moisture.

4. Fibreglass

This method is a bit more complicated and a little dangerous. Fibreglass will create a great finish that will protect your planter from moisture. Unfortunately, fibreglass can be dangerous if inhaled or touched while working with it so make sure you have the proper safety equipment.

5. Pond liner

Pond liner is another great option for lining planters. It can be quite difficult to work with. You will need to line the planter and then create drainage holes to keep your plants healthy.

Swell UK 4.5m x 6m Pond Liner (25 Year Guarantee)

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6. Varnish

Varnish is another effective way to protect wooden planters. Simply paint on the required amount of coats and you’re good to go.

Rustins Quick Dry Varnish Clear Gloss 250ml

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7. Spray-on liner

It is possible to get spray on plastic or silicone liners for planters. If you choose this option, you will need to prepare your planter before spraying on the required amount of liner. This type of liner does really well when used to protect wooden boxes, making them last so much longer.

Alternatives : Fibre Liners

It might be worth checking out these fibre liners that are ideal for planter boxes and hanging baskets. Whilst not 100% waterproof, they are a great way of lining planter boxes and flower pots.

10m Bulk Roll Co-Co Hanging Basket Liner (0.75m wide)

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Why you should line your planter boxes

There are quite a few benefits associated with lining planter boxes. Here’s what you can look forward to:

Improved durability

Plastic liners will offer your planters an improved lifespan. Without the constant moisture, it will take longer for rot to set in and destroy your planters.

Healthy plants

The correct amount of moisture will keep your plants healthy. If you have a planter that allows a lot of evaporation, then a plastic liner will be a great help when it comes to keeping your plants moist and in turn healthy.

thirsty plants in a lined planter

Thirsty plants will thrive in a lined planter. Image credit: @savoredjoy

Less rot

Planters will take longer to rot if protected by a plastic liner. Keep in mind that there will come a time when rot sets in, however. Some plastic liners don’t protect the wood completely after all.

More planter options

The use of plastic liners opens up the possibility of planters you didn’t even consider. These include coco coir planters and those without drainage holes.


Does a wooden planter box need a plastic liner?

Yes, wood planters will last much longer when lined with plastic. Plastic liners prevent moisture from being in constant contact with the wood. This in turn prevents the wood from rotting prematurely.

How do you waterproof a planter box?

How depends on the liner. If it’s a pot, simply place it inside the planter of your choice, if it’s plastic sheeting either glue or staple it in place. If you decide to rather go for the liquid version, you can either paint or spray paint it on.

What should I line the bottom of a planter with?

To prevent soil from falling out, you can place coffee filters or fine wire mesh over the drainage holes. You can also use a newspaper or cheesecloth for this purpose.

You might like: What can I plant in a flower box?

7 best waterproof liners for planter boxes (how to use)-min

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  1. Sarita
    February 27, 2023 at 6:44 pm

    I would love to know which linings are the safest for growing vegetables, from a microplastics and toxicity point of view.

    • Liz Berry
      June 6, 2023 at 11:50 am

      Hi Sarita, this is a good point and it’s tricky to find a waterproof lining that doesn’t contain plastic. I personally use coco liner, it’s made from natural coconut fibre and is really long lasting as well as food safe.


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