A raised garden bed is a great way to garden without putting too much stress on your back and joints. Garden beds keep your garden tidy, uncluttered, and improve the overall health of your plants.

The internet is crawling with DIY raised garden bed ideas, but know that some materials are best left alone when constructing your garden bed. You can customize your perfect design, but one question continues to play on a loop -- how long will it last? Most importantly, can you do anything to extend their life?

Understanding Raised Garden Beds

raised garden bed

Image credits: Alachua County via Creative Commons

Raised garden beds are great for older gardeners, those with limited mobility, and new mothers who want to continue working in their gardens. They're also good for your plants because they:

  1. Help control weeds
  2. Gives you complete control over the soil
  3. Prevents soil compaction
  4. Are easy to customize to suit your preferred material, height, shape, and color requirements
  5. Provide visual appeal

You can DIY your own raised garden bed from many materials, including galvanized steel, wood, and bricks. Although, there are several mediums to steer clear of such as: Styrofoam coolers, pressure treated wood, and cinder blocks.

How Long Will Your Raised Garden Bed Last?

The material you pick, the plants you grow, and your climatic conditions directly impact your raised garden bed's lifespan. Below is an overview of what you can expect.

1. Wood

wood raised garden bed

Image credits: High raised beds in organic vegetable garden via Flickr

Depending on the type of wood, a raised garden bed can last either very long or very short. Treated lumber beds can last 10-15 years, but because they're Alkaline Copper Quaternary (ACQ)-treated, they will leach some amount of copper into the soil that will eventually land on your plate if you're growing edible crops. This is why using treated wood isn't recommended.

It's better to use untreated wood even if it lasts three to six years, depending on the climate. When it comes to picking untreated wood, don't use pine as it has no resistance to rot or insects and can quickly decay. Red cedar, cypress, redwood, and oak are good choices.

You may have heard of composite wood, a popular landscaping choice. The lifespan of composite wood when it comes in correct with direct soil hasn't been tested yet, but according to experts, it is susceptible to cracks, mildew, and rot in mostly the same way as regular wood.

That said, if you live in a humid climate, avoid using wood as your raised garden bed material. This is because if the wood is put through moisture and doesn’t dry off properly, it will rot even faster than expected.

You should also avoid using wood if you're going to grow plants that need frequent watering because they could quickly invite rot. You can prevent this by lining your raised garden bed with a high-quality greenhouse plastic liner.

2. Masonry Materials

cinderblocks raised garden bed

Image credits: oliva732000 via Creative Commons

Masonry materials include concrete, stones, pavers, bricks, cement, and other construction materials. Cement is relatively cheap and readily available, making it one of the popular raised garden bed materials.

If buildings made from concrete and cement carry a lifespan of 50 to 100 years, your concrete garden bed is likely to last a lifetime! This is because concrete is:

  1. Resistant to humidity, rot, rust, and the sun's UV rays,
  2. Inedible making it resistant to pests, vermin, and insects,
  3. Able to withstand various weather conditions,
  4. Resistant to freezing and thawing.

Similar benefits apply to stones, bricks, and pavers, which makes them a safer, more long-lasting material for raised garden beds. Masonry materials are ideal for people who live in humid and cold climates.

If you live in hot climates, know that cement heats up faster, which could increase the soil's temperature and speed up water evaporation.

3. Plastic

plastic raised garden bed

Image credits: nick.whitt via Creative Commons

Plastic garden beds aren't prone to rotting and don't get infested with insects. They're portable and customizable, making them one of the popular materials for constructing raised garden beds. But is plastic safe for gardening?

Yes, but only if you pay close attention to the plastic you use. Plastic is categorized into seven Resin Identification Codes:

RIC 1

Polyethylene Terephthalate (PET or PETE)

RIC 2

High-Density Polyethylene (HDPE)

RIC 3

Polyvinyl Chloride (PVC)

RIC 4

Low-Density Polyethylene (LDPE)

RIC 5

Polypropylene (PP)

RIC 6

Polystyrene (PS)

RIC 7

Catch-all - acrylic, nylon, polycarbonate containing BPA, and polylactic acid.

If you're growing edible crops, use RIC 5; for inedible crops, it's best to use RIC 1, 2, 4, and 5. Avoid using RIC 3, 6, and 7 because they're known to leach dangerous chemicals into the soil.

Many recycled plastic manufacturers claim that plastic raised garden beds can last 25 years if you maintain them. However, plastic isn't ideal for people living in hot climates because direct sunlight can cause the plastic to crack.

4. Galvanized Steel

three raised beds

Image credits: mikecogh via Creative Commons

Galvanized steel garden beds are safe if your goal is to prevent zinc and metal leaching. The trick with using galvanized steel beds is to test your soil's pH levels to ensure it isn't acidic. Acid soils will accelerate zinc leaching, which will eventually land on your plate if you're growing edible crops.

To prevent metal and zinc leaching and to be able to grow acid-loving plants, use a high-quality greenhouse plastic liner to line your planter. Galvanized steel has a lifespan of 30 years, but if you have exposed it to elements and are using it to grow crops non-stop, check your steel beds every 15 years for rust.

If taken care of correctly your bed can last up to 30 years.

How To Make Your Garden Beds Last Longer

A raised bed vegetable garden with wax beans, lemon balm, mint, red leaf lettuce and tomatoes in a backyard garden

Image credits: Tracy Immordino via Shutterstock

You can do a few things to extend the life of your raised garden beds.

1

Line your wood and steel raised with high-quality greenhouse plastic liner to prevent the planters from degrading. Without a liner, wood beds will degrade faster from water, rot, and fungus, and steel will leach metals into the soil.

2

Don't use high-acidic compost or manure in galvanized steel raised garden beds without using liners, as that could cause leaching into the soil.

3

Pick the right spot for your raised garden beds. Understand the kind of material you're using and find out how the climate (sunlight, air, rain) will affect it.

4

Don't let grass or weeds grow around and between your raised garden beds. Not only will they steal your plant's nutrients if they have deep taproots, like thistle and dock, but they'll also attract pests and damage your garden bed.

5

Don't spray harsh chemicals near or inside your raised garden beds. Always use organic pesticides and homemade bug sprays to keep your garden pest-free.

6

Make hoop houses or build season extenders to protect your garden beds and plants from prolonged exposure to sunlight, rain, and small mammals.

7

Ensure your raised garden beds have drainage, as waterlogging can damage your planter's base and your plants.

8

Prepare your garden beds for winter by covering them if you don't intend to use them.

Thyme to Garden!

Raised garden beds are incredibly helpful and a worthwhile investment for older gardeners, those with limited mobility, and new mommies. Raised garden beds keep weeds away, provide visual appeal, are easy to customize, and give you complete control over the soil.

However, depending on the material they're made of, they can be short-lived or very durable. Keep your climatic conditions in mind before selecting your raised garden bed, and ensure they have drainage holes for healthy plant growth.

Leave your experiences, thoughts, and questions in the comment section! And share with friends and family who might find this helpful.

Happy gardening!