How to Line a Wooden Planter Box for Your Garden

You can get a lot of great wooden containers for cheap or even free. These can be anything from old soda crates to tool boxes. And they can be turned into a quaint DIY wooden container planter for use indoors or outside. Repurposing wooden containers into planters can make a rustic and organic design statement. Plus, its an eco-friendly choice to give new life to something that mightve just been thrown away.

Before planting in a painted box, check to see whether the paint contains lead. You can use a simple lead test kit found at many hardware stores. Edible plants grown in a container coated with lead paint can absorb the heavy metal. And lead paint chips can pose an environmental risk. Even low levels of lead can cause health problems, especially in children.

Wooden planter boxes are a classic and charming way to grow flowers herbs vegetables and other plants in your garden. The wood provides an attractive, natural look. However, without proper lining, a wooden planter can cause issues like soil erosion, rotting wood and dried out plants.

Lining a wooden planter box properly is key to protecting the wood and helping your plants thrive Read on for tips on the best materials to use and how to line planters for optimal growing conditions.

Why Line a Wooden Planter Box?

There are a few reasons why it is recommended to line a wooden planter before filling it with soil and plants:

Prevents soil erosion. Unlined planters can develop gaps over time where soil will leak out between the wooden boards.
Protects the wood from rotting. Direct soil contact encourages faster decay of the wooden sides of the planter.

Retains moisture. Planters are more prone to drying out, especially in hot conditions. A liner helps maintain evenly moist soil.
Allows for drainage. Excess water needs an escape route to drain out the bottom to prevent soggy soil.
Provides a smoother surface for roots. Fabric liners give roots something easy to cling to as they grow.

Extends the life of your planter. A proper liner shields the structure from damage while growing your plants.

What to Use to Line a Wooden Planter Box

There are a variety of effective options when choosing a liner material for a wooden planter:

Plastic Liners

Plastic planter liners are widely available and affordable. Look for:

Heavy duty polyethylene plastic sheeting

Thickness of at least 10-15 mil for durability
Size that fits your planter’s dimensions with extra to overlay the rim
Drainage holes pre-cut in the bottom

Plastic sheeting is the simplest liner to work with. Just place it in your planter, trim any excess material and start filling with soil.

Landscape Fabric

Also called weed block cloth, landscape fabric is an excellent liner choice:

Allows water drainage while blocking soil
Made from polypropylene or polyester material

Can be cut to fit any planter shape and size
Reusable from season to season
Biodegradable options are available

Make sure the fabric you choose is rated for landscape use and not burlap. Measure and cut fabric to size before lining your planter.

Pond Liners

For the most durable liner option, consider using pond liner:

Made of thick polyethylene or EPDM rubber
Withstands weather, sun exposure and soil acids

Can be shaped to fit into any planter design
Helps prevent wood rot with robust waterproofing
Provides insulation to maintain soil temperature

For a custom fit, you can use a heat gun to mold pond liner to the exact contours of your wooden planter box before filling.

Geotextile Fabric

As another robust choice, geotextile fabric is commonly used by landscapers:

Woven polyethylene material prevents soil erosion
Allows proper drainage and aeration

Naturally resistant to rot and degradation
Can be cut to size for any planter
Works for multiple seasons before needing replacement

Look for landscape grade geotextile fabric with good permeability to line your planter box.

How to Line a Wooden Planter Box

Lining your wooden planter box is a simple process:

Measure the interior dimensions of your planter box – length, width and depth.
Cut your lining material several inches larger than these measurements on all sides. It’s easier to trim off excess than to have a liner that’s too small.

Place the liner inside the planter, pressing and molding it to contour to the sides and bottom.
Trim any overlapping edges with scissors or a utility knife so the liner lays flat.
If needed, use a heat gun to soften and manipulate plastic or rubber liners for a smooth custom fit. Be careful not to melt the material.

Check that liner drainage holes align with those in your planter box. Add more if needed.
Fill the lined planter with good quality potting soil suitable for your plants.
Start planting! Your liner will help retain moisture and nutrients.

Tips for Choosing a Planter Box Liner

Match liner durability to planter longevity. Short term planters can use plastic sheeting while permanent planters need pond liner.
Check that the liner material is non-toxic if you are growing edibles. Certain plastics can leach chemicals.
Allow excess liner to drape over the planter rim to prevent soil escaping between boards.

Pick a neutral color liner like black or brown to remain hidden behind plants.
Make sure the liner doesn’t have its own drainage holes that could clog those in the planter.
For large planters, line just the bottom rather than all sides to allow some natural moisture loss.

Maintain Your Lined Wooden Planter Box

A properly lined planter will last for many years. Here are some tips for keeping your planter in top shape:

Inspect periodically for liner tears or gaps where soil could escape. Repair as needed.

Refill soil that sinks over time to maintain proper plant coverage.
Keep the planter attached to a drip irrigation system for easy watering.
Monitor soil moisture and only water when the first few inches become dry.

Fertilize plants according to package instructions to nourish through the liner.
Replace plastic liners annually as they become brittle. Use rugged materials like pond liner for longer duration.
Keep the planter protected from harsh weather with a covered location or winter storage when not in use.

Lining your wooden planter box takes a small upfront investment of time and materials, but pays off with healthier plants andsaved wood integrity for seasons to come. Try one of these effective liner options to start reaping the benefits!

Preserving Wooden Containers

You can make your wooden planter last longer by sealing it with a chemical. This is only necessary if you’re only growing plants for looks and not for eating. Apply it to both the inside and outside surfaces of the planter.

If you want to eat your plants, though, you should stay away from regular wood sealers because they often contain harmful chemicals that can seep into the soil and be absorbed by the roots of the plants. For containers that will grow food, there are some wood preservative treatments that are safer than chemical wood sealers:

People think that paint-on products with acypetacs (a common brand name is Cuprinol) are safer than chemical sealers. Chemical sealers will work, too, but the wood will need to be cared for more often.
Boron salt-based water-based preservatives are thought to be safe; they are usually used in paint or gel form. But they don’t stick well to wood and need to be reapplied often.
Linseed oil, which is made from flaxseed, stays good on wood for a long time but takes a long time to dry. Stay away from things that are mixed with solvents, like mineral spirits. Also, keep in mind that linseed oil can catch fire before it hardens.

Selecting Wood for DIY Planters

Wooden planters dont 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.

The right kind of wood and proper care, on the other hand, can make wooden boxes last for many years. Here are some types of wood that won’t rot or get damaged by bugs or other things:

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 dont 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’re going to use pressure-treated wood, you might want to only put ornamental plants in your containers.

Also, never build a planter out of creosote-soaked railroad ties, whether the plants will be edible or just for looks. This oily preservative contains hundreds of chemicals that can cause many adverse health effects.

The Spruce / Adrienne Legault

Lining Wood Planter || DIY Garden

FAQ

What to line a wooden planter box with?

– Pond liner or geotextile fabric provides excellent durability and helps prevent wood rot. – Measure the interior dimensions of your wooden planter and cut the pond liner or geotextile fabric to fit. – Place the liner inside the planter, ensuring it covers the bottom and sides completely.

Do wooden raised beds need to be lined?

Many experienced gardeners recommend lining raised beds for these reasons: It provides insulation for the soil and helps control temperature fluctuations. It helps with soil retention. It separates weeds from seeds.

What do you put in the bottom of a wooden planter for drainage?

One of the best things to put at the bottom of a planter for drainage is broken pieces of pot. You can use any unwanted plant pots or chipped crockery for this – simply smash them up into small to medium-sized pieces. Adding a layer of broken pieces of pot like this will prevent compost loss out of the drainage holes.

How do you line a wooden planter?

A mix of campanula, sedum and clovers would grow well in here. You can use this process to line wooden planters of any size. The one I’ve lined today is 60 by 40 cms, but I have also lined an 8 metre by 2 metre raised bed with a mixture of compost bags and rubble bags. That was 4 years ago and it’s still going strong.

Do you need a liner for a planter box?

Pro tip: If you have a deep planter box, it’s best to use a liner to encourage good drainage as the potting soil may compact due to its weight. It’s also useful to put a liner if you’re going to place the planter box on grass. The other time you may need to use a liner is if your planter box is just a wireframe.

How do you line a planter box with plastic?

Plastic sheeting is a fantastic option if you want a more durable liner. Attach it to the interior of your planter box with staples or adhesive. Just be sure to make holes for drainage in the plastic. Most plants will rot and die if left in water for too long. Click here for this product on Amazon.

Should I line my planter box?

Here are some benefits you can enjoy if you line your planter box: The liner will enable you to remove the plant from the pot, allow the roots to drain correctly, and then replace it when you’re planting in a pot or planter without drainage holes. Liners protect the soil from extreme temperature fluctuations.