If you are thinking of building or buying a raised garden bed, then you probably asked yourself, if you should remove the grass under your raised garden bed or not. So to help you create the perfect conditions for your raised garden beds.
So do you have to remove grass under a raised garden bed? In short, yes. If you leave the grass under your garden bed and just cover the grass with topsoil, then it can still grow, causing a lot of problems for you and your raised garden bed later on. It could even manage to get all the way back up to the level of the garden bed and invade your newly created bed.
Can Grass Still Grow Even if You Cover It With Soil?
The answer to this question can vary. You can completely kill the grass with topsoil. But then again, you can never be sure if it’s dead or not.
If you plan on a lower raised garden bed, the added soil might not be thick enough to smother the grass underneath. The grass will be able to grow over the soil after a while.
If your raised garden bed is higher, there are more chances to suffocate the grass underneath. But, again, you can’t be sure. Also, no matter how thick the soil is, suffocating grass will take a long time.
You can never trust killing grass by adding soil over it then. Instead of grass, you should look for another base for your raised garden bed. If you do, then you won’t have to worry about whether the grass is dead or not.
What Should be Under a Raised Bed?
The best base for a raised garden bed is soil.
You need to remove the sod in your raised garden bed area to do this. There are many herbicides that do the job for you.
But if you want to go natural, then there are effective methods to do that as well. Here are some of the natural methods.
This method is for those who are willing to put in the hard work. Once you measure your area, you will need to uproot the grass over it. If you leave roots behind, then it can grow back over your raised garden bed.
The problem with digging the soil is that you remove all organic material. Organic material is important because it contributes to a plant’s health.
Without it, you will need to add even more fertilizers to grow your plants in your raised garden beds. Digging sod can also remove vegetation cover, thus exposing it to weed seeds. You don’t want weeds living in the same space as your flowers or vegetables.
Different tiller machines serve different purposes. The small ones are for previously-worked on gardens. The bigger tillers are for untouched sod. If you want to use a tiller, then you should know what kind of sod you are dealing with.
Tillers break the sod and soil into small pieces. With the disrupted soil, the sod is now uprooted. Be careful to remove all remaining grass clumps.
If you leave one behind, then it can start growing again.
This method is susceptible to weed seeds. You don’t want to have a problem with weed germination later on. To avoid this, wait a while for these weeds to grow.
Keep the area moist so growth will be faster. Once you remove the grown weeds, you can start planting.
You don’t have to disrupt the soil to remove the grass. The smothering method is the longest process but requires the least work. There are 3 materials that you can use to smother sod.
People like using plastic because of its intensive heat. Once you anchor the plastic down, it produces so much heat that anything underneath it dies. It also kills grass because of the lack of light.
Using plastic is not the best material though. This is because it can also kill beneficial organisms. And since it is not biodegradable, you will need to remove it before planting your garden.
The other materials are cardboard and newspaper. You can interchange these two materials. To hold the layers of newspaper or cardboard in place, pile grass clippings, leaf molds, or composts above it. Though it does not produce much heat, it does keep more light out.
Over time, the grass beneath will die. This is because of broken down chlorophyll and stopped photosynthesis. It does take a few months to kill the grass underneath though. It is important to note that you should use newspapers with black and white ink only. Other colored ink can place metals in the soil.
If you want these methods to be easier, then you should mow the grass as short as possible.
With these methods, you can get the soil base that you need for a successful raised garden bed.
Can I Put A Piece of Wood or Stone Under the Raised Bed as A Base?
You might have noticed that some people put stone or wood in their raised garden bed bases. Should you copy these raised garden beds?
Plain soil is enough to grow healthy plants. But if you want your raised garden beds to have more functions, then you can add wood or stone bases.
Stones work wonders with irrigation. Most flowers and vegetables need well-draining soil. If your soil is so compact under, then there won’t be any space for the water to wash away. This can kill your delicate flowers and vegetables during the rainy season.
Avoid a solid stone base, because the raised bed needs drainage and a solid stone base will hinder easy drainage.
If you add stone to your base, it will work as a drainage. As the water enters the soil, the stones will allow breathing space that drains it away. You don’t have to worry about too much moisture in the soil anymore. And unlike soil, stones don’t degrade or compact no matter how much water passes through it.
If you want good irrigation in your raised garden beds, then scatter stones in the base. Do this before you add the topsoil. If you want it to be more effective, then take the time to even out the stone layers. This will ensure that each square inch will have stones to drain the water and moisture.
People use wood so that the soil is not too compact underneath. This is its main purpose. But, wood is very susceptible to rot. If you decide to place wood in your base to protect the soil, make sure that it is rot-resistant.
Cedar and redwood are the best wood bases. They last longer than other woods. This is because they are naturally resistant to rot and insect infestation. You can expect these woods to last 10 to 20 years in a raised garden bed.
Other durable woods are wood composite products and pressure-treated woods. Stay away from pressure-treated woods if you plan on planting vegetables though. This wood consists of a lot of chemicals, which can leach into the soil and plants. You don’t want to be eating vegetables that have these chemicals!
Should I Put A Bottom in My Raised Garden Bed?
You might feel your raised garden bed is not safe unless you block it from the ground. So you think that a bottom will help with that.
Adding bottoms or solid foundations to your raised garden bed is not a bad idea as long as you watch out for proper drainage. But it will need a lot more work than necessary. First, you need to make a frame with a bottom. Then you need to bore holes in that bottom so that water can flow out. Finally, you need to put everything together. It does take a lot of hard work.
But placing a bottom comes with some benefits as well. You don’t have to worry about anything in the ground – weeds, insects, and all that. If you add wheels, there is the extra benefit of being able to move your garden around.
You can place a bottom if you want to. But you have to be willing to do the extra work. In the end, having no bottom is as great and safe if you do it the right way. It is all about your preferences.
A raised garden bed is so beneficial. It keeps weeds away, barriers pests out, prevents erosion, avoids soil compaction. It also allows you to garden without hurting your back by bending over.
It is very aesthetic to look at. You can separate your plants, flowers or vegetables. You can enjoy the planting experience more. You can watch the plants more as it grows. The list can go on and on with raised garden bed benefits.
If you follow the tips that you learned here, then you are on your way to creating the best-raised garden bed.
There is no right and wrong answer. It is all about finding what base works best for you, your plants, and the ground. So enjoy the experience and be well on your way to being an expert in raised garden beds.