Should I Put Landscape Fabric Under a Raised Bed? Get the Real Dirt

So you’re building a raised garden bed and the big question hits: should you put landscape fabric underneath? A lot of folks reach straight for the roll, thinking it’s the key to a weed-free garden. But things aren’t as cut and dry as those perfect product ads make it seem.

Landscape fabric is like a barrier. It’s meant to block weeds from pushing up into your soil while still letting water drain through. Sounds perfect, right? But here’s the twist: it also locks out earthworms and other good stuff that helps soil stay loose and full of nutrients. Over time, your soil could end up compacted and lifeless—kind of the opposite of what you want if you’re growing tomatoes or lettuce for those homemade salads.

If you’re hoping for healthy plants and low-hassle gardening, it’s worth thinking carefully before rolling out that fabric. The best setup depends on what you’re actually dealing with under your bed: is it clay, rock, grass, or maybe aggressive weeds you’ve battled before? Each background calls for a different tactic. Don’t want to sacrifice soil health or keep pulling weeds all summer? Let’s get into what really works under a raised bed, so you can spend more time harvesting and less time regretting a hasty choice.

• What Does Landscape Fabric Actually Do?
• Pros and Cons: Does It Help or Hinder?
• Better Alternatives for Your Raised Bed
• Tips for Setting Up a Weed-Free, Healthy Bed

What Does Landscape Fabric Actually Do?

Alright, let’s clear this up—landscape fabric is made from woven or non-woven material that acts as a barrier between your garden soil and whatever’s underneath. The main reason people use it under a raised bed is to keep weeds from sneaking up into the nice soil you’ve added on top. It blocks sunlight from reaching weed seeds, so it disrupts their growth right at the source.

But it doesn’t stop there. Landscape fabric is designed to let water and air pass through so your soil gets the moisture and oxygen your plants need. In theory, this keeps everything balanced—a dry, airless barrier would just turn your bed into a soggy mess or a rock-solid brick.

Here’s where it gets interesting: it’s not just about weeds. Some folks use landscape fabric to keep grass and bug-laden dirt from mixing into their raised bed soil. It can also help hold your best dirt in place if your backyard is full of gravel or heavy clay. Not all fabrics are created equal though; the cheap stuff often tears or breaks down within a season, while high-quality commercial fabric can last several years but doesn’t biodegrade on its own.

Below is a quick look at how different types of landscape fabric compare:

But remember, while weed control is the big selling point, this stuff isn’t invincible. Soil and mulch on top can break it down, roots can push through, and even worms might avoid the area if the barrier is too tough. So, if your goal is straight-up kitchen gardening and building up really great soil, be sure you’re using landscape fabric for the right reasons—otherwise, there are better options out there.

Pros and Cons: Does It Help or Hinder?

If you’re thinking landscape fabric is a no-brainer for your raised bed, it’s totally fair to ask—does it really make things easier, or are there some surprises once your veggies start coming in?

• Pro: Blocks major weeds. Seriously, that fabric puts up a tough fight against grass and big weed roots trying to break into your garden. If your yard used to be a weed jungle, you’ll get a little breathing room.
• Pro: Holds soil in place. Some yards have major run-off, and the barrier underneath keeps your good soil from escaping every time it rains hard.
• Pro: Keeps out pests like moles. It’s not perfect, but some folks notice fewer critters tunneling up from below when there’s a barrier.
• Con: Stops earthworms and critters from doing their thing. You want worms and bugs mixing up the dirt, making it fluffy and full of nutrients. The fabric shuts most of that down—no worm highways here.
• Con: Water drainage can get weird. While it’s supposed to let water through, cheap fabric tends to clog up, especially after a season or two. Roots hate sitting in soggy soil, so your plants can suffer if things get swampy.
• Con: Roots hit a wall. If you use shallow beds, plant roots may not grow deep enough. They’ll hit fabric and stop or curve back up, which messes with strong, healthy growth.
• Con: Long-term breakdown. Even top-quality fabric can break down after a few years, turning into a tangled mess mixed with roots—not fun when you try to freshen up your soil later on.

Take a look at how landscape fabric actually stacks up in real gardens:

Bottom line: landscape fabric can help with short-term weed control, but it can bite you later by hurting soil health and making maintenance messier. If you’re growing veggies for the long haul, there are usually better ways to build your bed. But if you’ve got a short gardening season, bad weed trouble, or rocky ground, it still has a place—just don’t expect a miracle fix.

Better Alternatives for Your Raised Bed

If you’re not sold on landscape fabric, you’ve got options—ones that are better for both your soil and your plants in the long run. You don’t want to choke off the life from your garden. Here’s what actually works under a raised bed if you want to keep weeds out but still let your soil breathe.

• Cardboard or Newspaper: This is hands-down the favorite among kitchen gardeners. Lay down a thick layer (think six sheets for newspaper or one sturdy layer for cardboard). It blocks most weeds but breaks down in a season, letting roots and earthworms move freely. Plus, these materials are cheap and often free—bonus if you’re recycling moving boxes like I did the last time Rufus chewed through one.
• Mulch: Wood chips, straw, or pine needles act as a weed barrier on top of the soil, but some folks also lay them beneath the bed before filling. They help block weed growth and slowly break down, adding nutrients. Just double-check you’re getting untreated mulch if your veggies are going in the ground.
• Just Soil: If the ground under your raised bed is mostly free of weeds or you’re setting up over plain dirt, you honestly don’t need a barrier at all. Deeper beds (think 12”+ high) smother most existing weeds, making fabric or similar stuff kind of pointless. Pull out tough sod or major roots, fill the bed, and you’re set.
• Hardware Cloth (¼" mesh): Not about weeds here, but this is a top trick for blocking moles, voles, or burrowing pests. Lay it flat under your raised bed before filling with soil, and say goodbye to critters eating your carrots from below.

What about results? A 2022 community garden survey showed that gardeners who used cardboard under raised beds reported the same weed control as those who used landscape fabric after one year—but they rated their soil health almost 40% higher. Nobody wants dead dirt under their veggies.

Another thing—avoid using plastic sheets. Sure, they block weeds, but they also block water, mess with your soil’s health, and can cook your plant roots in the heat. Stick with solutions that let water and air pass through.

Think about what’s under your bed now, your weed problems, and your long-term soil goals. Choose the method that fits your setup and don’t get fooled into thinking there’s only one right answer.

Tips for Setting Up a Weed-Free, Healthy Bed

Keeping your raised bed both healthy and weed-free is doable, but it’s all about how you set things up from the start. Forget about shortcuts—what you do now will save you hours later during the growing season. Here’s what actually works, based on real-life trials and research from trusted extension services.

• Clear the ground first: Dig out sod, weeds, and roots under where your bed will go. If you lay a bed right on top of grass or mature weeds, those suckers will find a way through, even if you use landscape fabric.
• Use cardboard or newspaper: One or two layers at the bottom will block most weeds. Unlike plastic or synthetic barriers, these break down naturally and let water and worms move freely between the ground and your garden soil. Lay the sheets with overlaps so there are no gaps—trust me, weeds love gaps.
• Fill with quality soil: Use a mix of compost and topsoil. Don’t just shovel in plain dirt from your yard. Plants in kitchen gardening beds do way better with soil that drains well and is packed with organic matter. For a good rule of thumb, mix 60% topsoil, 30% compost, and 10% potting mix or other organic material.
• Mulch, mulch, mulch: Once you’ve planted, add a 2–3 inch layer of organic mulch (like straw, wood chips, or shredded leaves) on top. Mulch blocks light from reaching weed seeds, keeps moisture in the soil, and slowly breaks down to feed your plants.
• Stay on top of weeds early: The little weeds you see in spring? Pull them before they grow up. Weeds are a lot easier to control if you don’t give them a chance to settle in. Rufus, my dog, always manages to dig up a few himself, but I wouldn’t rely on a canine crew for this task.

Want to see how different weed barriers stack up? Here’s a quick table comparing their impact on soil health and weed control in raised beds:

Bottom line? Your best bet is a practical combo: remove weeds, use cardboard or paper, fill with rich soil, and top with mulch. This approach makes your life easier, helps your veggies thrive, and gives those helpful earthworms a free pass into your garden.