In recent years, no-till gardening has become all the rage. People have been growing without plows and tillers for hundreds of years, but more people have come to recognize the benefits of leaving the soil undisturbed. They’ve seen microbial life flourish, erosion and compaction decrease, and plant health increase.
Along with providing environmental benefits, no-dig raised bed gardening is easy! You don’t need heavy machinery like a rototiller, and you don’t have to rebuild the beds each year. Plus, no-dig beds often experience less weed pressure, meaning you’ll spend less time pulling these unwanted plants.
If you want to join the no-till revolution, raised beds are a great place to start. I’ll explain the most popular method to make no-dig raised beds and share multiple helpful tips to consider.
No-Dig Basics
No-dig is just another term for no-till gardening. Both refer to methods that minimize (or eliminate) inverting and mixing the soil. That means no tilling, double-digging, or aggressive raking. The overall goal is to create an environment that fosters a healthy soil microbiome.
Just think—each time you run a rototiller, the blades rip up aggregates, destroying the homes of beneficial bacteria and fungi. As the dirt settles, it often becomes compacted, leading to an even less hospitable environment for critters like earthworms, beneficial bacteria, and nematodes.
While it’s easy to think eliminating tillage leads to compaction, the opposite often proves true; as bacteria and fungi are allowed to thrive, the soil becomes light, fluffy, and prime for healthy plants.
Of course, there is some debate over what’s considered “tillage.” Does raking compost into the top inch of soil count? What about pulling out deep-rooted weeds? While I’m not here to answer these questions, I’ll say it’s better to focus on the overarching goal of disturbing the soil as little as possible rather than focusing on the nitty-gritty details.
Along with minimal disturbance, no-dig gardeners also focus on keeping the ground covered with plants as much as possible. That’s because roots add organic matter and supply microbes with a continuous food source, and plants help prevent erosion. This method of growing also focuses on increasing organic matter through additions of compost, mulch, and other organic materials.
How to Form No-Dig Raised Beds
Forming no-dig raised beds is an easy way for home gardeners to take advantage of the benefits of no-till growing. However, many growers don’t know where to start. Although there are multiple ways you can form raised growing areas without tilling, I’m going to explain a popular method that involves cardboard and compost.
Famed no-dig gardener Charles Dowding uses this process on his English farm, but it’s adaptable to many environments and climates. This video provides the perfect visuals:
In short, this method involves trimming down underlying vegetation like grass or weeds, laying cardboard on the ground, and then covering the cardboard with multiple inches of compost.
The cardboard smothers the remaining vegetation, and the compost provides a nutrient-rich material in which plants can grow. Over time, the cardboard breaks down, and roots can access the native soil.
Here are the steps to take to using this method.
Design Your Beds
Before you start building, make a plan for what you want them to look like. I recommend keeping them under three feet wide to make it easy to reach all sides. However, you can make them as long as you like. If you’re building multiple beds next to each other, you should also think about pathway width and take this into account when measuring the area.
You should also account for a buffer along the edges. For example, if you want to build a 3×8-foot raised bed, you should find a 4×9 area for the bed to go. This extra room decreases the chances that weeds will creep into the edges of the bed.
Choose a Suitable Area
Look at the sun exposure and choose an area with suitable light. Most vegetables and herbs require at least eight hours of direct light to thrive, but some landscape plants can thrive in partial or full shade.
After you examine the light, look at the soil. While it’s okay to build your raised beds on any soil type, avoid areas with ponding water and poor drainage. It’s okay if the soil is high in clay, feels hard, or contains lots of rocks. However, you should avoid on top of concrete pads or other impervious surfaces.
Lay Down Cardboard
Once you’ve designed your no-dig raised bed garden area and selected a suitable spot, it’s time to start building. Laying down sheets of cardboard is the first step in the construction process. Your goal is to completely cover the area so that no weeds can break through. Therefore, you should overlap the pieces by a few inches.
Cardboard often has remnants of staples or tape, so try to remove these before placing the material in your garden. While this can seem like an arduous process, removing these unwanted pieces of plastic and metal ahead of time prevents you from having to sift through it later.
If you’re putting the cardboard down during a dry time of year, it’s helpful to water it after it’s on the ground. The moisture will keep it in place and prevent it from buckling after the compost is on top. If the ground is already moist, there’s no need to water.
Add the Compost
Once the cardboard is flat on the ground, it’s time to apply compost to the areas where you’d like your raised garden. The amount depends on your goals as well as the native ground. If you’re working with lots of weeds and want to start growing ASAP, add three to five inches of compost to the area where you’d like your raised bed. However, if it is relatively weed-free, you can add as little as two inches of compost.
I find the easiest way to add the compost is with a wheelbarrow, shovel, and rake. You can dump loads of compost and then use a rake to smooth them into their desired shape.
The type of compost is extremely important, and adding low-quality or partially decomposed material can lead to lackluster results. When you’re looking at amendment options, keep these factors in mind.
No matter what materials you’re starting with, composting involves using microbes to break down large organic items into smaller particles. Microbes will continually break organic materials down until they reach their final stage and the pile becomes “finished.” If the pile is hot to the touch, it’s still active.
Adding active compost to raised beds can cause numerous issues. As it continues to break down, it settles. Therefore, if you add three inches of compost, you may have only one inch of material after it sinks. Another problem with actively decomposing material is that not all the nutrients are available to plants.
If you only have access to hot compost, you can still use it to create raised beds. However, purchase it a few months before you plan to build your raised bed. Let it sit in your yard during this time, and turn the pile with a shovel every week or so. This will allow it to fully break down before you add it to your beds.
All compost is made of organic materials, but you can use all kinds of substances to make it. These include “brown,” carbon-rich materials like wood chips and cardboard and “green,” nitrogen-rich materials like animal manure, grass clippings, and food waste. Ideally, it is made with a 2:1 to 4:1 ratio of browns to greens.
If it is made solely from carbon-rich materials like wood chips or brown leaves, the product will contain a high amount of carbon and little nitrogen. This will still add organic matter to your garden, but it won’t provide much nitrogen. In fact, it can steal nitrogen from the surrounding soil, leading to nitrogen-deprived plants.
While many herbicides will quickly break down in the environment, a few persistent chemicals can remain intact for months or even years. Therefore, herbicides originally used to control weeds in a field of wheat or barley can end up in a pile of finished compost. The best way to test for herbicide contamination is to grow a test crop in a sample of the amendment. If the plants show signs of herbicide damage, avoid using this amendment to create your raised beds.
Manage the Pathways
If you’re building multiple raised growing areas, you’ll end up with pathways. There’s not one right way to handle these paths, but you should think about how you’ll keep them free of mud and weeds.
One popular option involves spreading wood chips over the paths. The material covers the surface, preventing erosion and weed germination. Wood chips will break down over time, so be prepared to replenish them every year or two. However, as they decompose, they’ll add rich organic matter to the soil.
You can also try planting white clover or low-growing grass to create living pathways. These plants may require occasional mowing, but they’ll keep the soil in place and inject organic matter into the soil.
Another option is to leave the pathways bare and regularly cultivate them with a hoe. These paths will be more susceptible to erosion, but you won’t have to worry about mowing or hauling wood chops.
No-Dig Raised Bed Questions and Considerations
The above steps will let you easily form raised beds. However, you still may have questions about the process. Here are a few questions and thoughts people often encounter when building their beds.
Aerating Before Building
While it’s clear you should stay away from tillage, you may be wondering whether or not you should aerate the soil with a digging fork or broad fork. After all, many people claim that these tools simply aerate the soil rather than truly disturb it. In the end, your ideal circumstances determine whether or not forking is beneficial.
Charles Dowding has been experimenting with and collecting data on no-dig garden beds for years. In one trial, he compared unaltered beds with those he loosened with a digging fork each fall. He found that the unforked beds produced bigger harvests than those he aerated.
With that said, initial aeration is useful in some circumstances. For example, if you’re dealing with soil that’s truly compacted or fighting a hardpan layer, a few passes with a broadfork will prove helpful.
Enclosing the Sides with Wood
When people think of raised beds, they often imagine products built out of rot-resistant cedar or durable metal. While these types of raised beds make gardening accessible for everyone, they’re not the only type of raised bed available.
After you make a raised bed following the cardboard and compost method, there’s no need to enclose the sides with wood. The compost may change its shape a bit over time, but you can easily place it back with a shovel or rake. That said, you’re welcome to enclose the sides of the bed with pieces of wood or metal.
Tarping Before Planting
One of the many benefits of no-till gardening is the lack of weeds. In theory, once the weed seeds on the top layer, they will germinate and die. You should not experience any more weeds. A few seeds may float in with the wind, but you won’t be bringing up weed seeds from a few inches under the surface.
However, perennial weeds may still be an issue. If you know your future garden area is home to weeds like Johnsongrass, thistle, and Bermudagrass, the area may benefit from a few months of tarping. Laying a UV-resistant tarp on top of the ground will block the sunlight and cause these persistent weeds to die. Once they’re dead, you can lay down cardboard and compost to form your beds.
