If you are contemplating starting a garden, you are likely thinking about building or buying raised beds (an elevated bed that is relatively small). Raised beds are very popular and have several benefits. The other option to consider is growing directly in the ground. One of the biggest advantages of in-ground beds is that the start-up cost is lower. Both approaches have advantages and disadvantages, but neither is better than the other. In my home garden, I apply both approaches and have had equal success (and failures) with both. The video below will take you through the process of preparing both a raised and an in-ground garden bed. Subsequently, the write-up below the video summarizes the key points of the video.
“The glory of gardening: hands in the dirt, head in the sun, heart with nature. To nurture a garden is to feed not just the body, but the soul.”
– Alfred Austin
SITE SELECTION
Before you begin to plan out your beds, there are a few things to consider. First, and most importantly, you need to choose a location that receives at least 6-8 hours of sunlight during the day. Experts believe that north to south is the best orientation for a garden in the Northern hemisphere because this gives the most sun exposure. Second, you need to kill the vegetation or turf grass that may be inhabiting the area you choose. You can either cover the area with black plastic or with a layer of mulch and leave in place for at least one month. In preparing our new garden beds, we covered the area with leaves in the fall and let the leaves stay in place during the winter. Then, in the spring we raked the leaves off the area and began bed preparation.
SITE PREPARATION
Good healthy soil is full of life and an important goal should be to incorporate as much of the native soil as possible (if the soil is not contaminated) from your location into your garden bed. Sometimes, it may seem easier to purchase topsoil but, in most cases, it is better to amend the soil you have. If you do need to purchase topsoil, it is important to understand that there is no official definition for what we refer to as topsoil. I have looked at the ingredients of many bags labeled as ‘topsoil’ and each is different. In many cases, no ingredients are listed. If purchasing topsoil in bulk from a garden center, inquire about the composition of the soil and whether a pH test has been done. Visually inspect the topsoil, it should be free of foreign materials (stones, glass, plastic) and should have an earthy odor.
For more guidance on starting a vegetable garden, please reference my blog post titled “Five Steps to Starting your Vegetable Garden”.
WORKING THE SOIL
When you establish a garden, you will need to disturb the soil in the beginning. For our home garden, we chose to manage this process with hand tools. Yes, this was a lot of work, but due to the number of rocks in our soil, renting a rototiller did not make sense. The size of our new garden is 15 feet by 30 feet. The method we found useful for capturing the native soil was digging up the sod pieces, letting them dry out and then using a wire mesh to sift out the soil into a wheelbarrow. This method required the following tools: basic turf edger (9-Inch by 4-3/4-Inch Round Blade), square flat shovel (6 1/4 x 9 1/2), forged cultivator (three prong rake).
I demonstrate the process in the video and have listed the steps below.
- Use the edger to create a 10-inch square approximately 4-6 inches deep
- Take the flat shovel and slice under the square of sod
- Use the fork to lift the piece of sod
- Turn the sod upside down and let dry out
- “Sift” the sod piece over the chicken wire directly into a wheelbarrow
- Dump the soil into your garden bed
In addition to capturing the soil from the sod pieces, it’s also good to ‘double dig’ the garden bed. This simply means working the soil with a spade and spade fork to loosen deeper layers of soil. Our soil has a lot of rocks and we were able to remove many of the rocks via this double dig process. There is nothing worse than encountering a rock deeper in your garden bed. This native soil should then be amended with organic matter as I describe in both the video and below in “raised bed preparation”.
RAISED BED PREPARATION
There are several advantages to raised beds that include:
- Less soil compaction because the area of the bed is clearly defined and thus not prone to being walked upon
- The soil warms up quicker in the spring
- Less soil erosion due to the borders around the raised bed
- Less bending needed to maintain a raised bed
- Raised beds add beauty to the landscape
- Good choice for areas where the soil is of poor quality (or there is no soil)
The primary disadvantage of a raised bed is cost. Cost to both build the raised bed and fill the bed with soil. Raised beds also dry out quicker and with therefore require more frequent watering.
Raised bed construction
Raised beds can be made in just about any shape desired. Here are some key considerations:
- The raised bed frame should be at least 6 inches high and no wider than four feet. With a four-foot-wide bed, be sure to leave enough space around the bed so you can access the bed from the two opposite sides. The average adult can reach about two feet into the garden from each side.
- Raised beds can be 18-24 inches high to allow someone to sit while gardening or higher to allow gardeners to stand.
- Options for construction include masonry landscaping blocks, stone, rot-resistant cedar, redwood, painted pine boards, vinyl or other materials.
- The beds and area should be as level as possible.
- If there is a concern about the soil, place black plastic under the bed to ensure that the roots do not reach the contaminated soil. Provide holes at the edges of the bed to allow for water drainage.
- Paths between the beds wide enough to fit a wheelbarrow and walk comfortably.
Raised bed soil
If you have good soil in the area of your raised bed, I recommend that you incorporate this soil within your bed as I demonstrated in the video. You will also need to supplement your native soil with purchased soil. I used the following recipe for filling my raised bed:
- 50% topsoil (including the native soil)
- 25% vermiculite or sand (for aeration)
- 25% compost (for maintaining an even moisture level)
It is often less expensive to purchase these ingredients in bulk but can also be more work to then transport these bulk materials to your raised bed. We have tried both methods and find it easier to purchase bags. When purchasing in bulk, talk to the garden center about the soil composition and ask whether a pH test was performed (ideal range for a garden is 6.0 -7.0). If purchasing bags, be sure to read the ingredients listed on the bag. When no ingredients are listed, then look for a product where the ingredients are listed. We used 10 cubic feet of ingredients to fill ~7 inches of a 48 square foot bed.
IN-GROUND BED PREPARATION
In preparing an in-ground garden bed, what you are doing is leveraging the native soil. In the long run, improving native soil may be much less expensive and more environmentally friendly and sustainable. Let’s first look at other advantages of in-ground garden beds.
- Less costly. The start-up cost of an in-ground bed is less than a raised bed. You do not need to purchase or make a frame for the garden and you will not need to purchase a large amount of soil to fill an in-ground bed.
- Use of existing native soil. It can be challenging to find and purchase real topsoil and thus it is often better to improve what you already have. Soil that is properly amended has benefits that are not found in man-made soil.
- Less startup work. You do not need to acquire the materials and build a raised bed.
- Lower water requirements. In-ground beds will not dry out as quickly as raised beds and therefore require less water.
The disadvantages of an in-ground be are opposite of the benefits of a raised bed. In preparing my in-ground beds, I incorporated the following ingredients into the native soil.
- 75% compost
- 25% vermiculite (or sand)
I followed the process described above in “Working the soil”. After the turf was killed, I dug up the sod, captured the native soil from the sod and then “double dug” the in-ground bed. I then incorporated the compost and vermiculite into the native soil. With an in-ground bed, it is helpful to place stakes at the corners of each bed to clearly delineate the borders of the beds.
ON-GOING MAINTENANCE
Whether you choose to do raised bed or in-ground gardening, there is on-going maintenance to remember.
- Once every three years, you should consider performing a soil test of your garden beds. I recommend performing a soil test at the end of the first season to better understand the condition of your soil and how your soil may need to be amended.
- Each year you should add at least 1-3 inches of compost to each bed.
- Rotate your crops each year to prevent disease. See my blog post on “Crop Rotation for the Home Gardener” for more information.
- Cover your beds when not in use. You can cover with a layer of organic mulch such as straw or you can use cover crops.
- Mulch the pathways between your beds with a few inches of wood chips to cut down of weeds. Consider first laying down a piece of landscape fabric or cardboard to help control weed growth.
- Plan irrigation. Ensure that you have a water source and that water freely drains through the soil. Experts consider the most effective irrigation for garden beds to be “drip” irrigation. Drip irrigation is simple and efficient and delivers water directly to the roots. Other irrigation methods include sprinkler and hand watering. The problem with sprinklers is that you are generally watering outside the beds.
- Before the start of your growing season, give the beds a once-over with a garden fork or other cultivating tool. Then rake in new compost and fertilizer to be ready for planting.
REFERENCES
Cornell University Cooperative Extension: https://archive.org/details/RaisedBedGardeningCornellUniversity
University of Georgia Cooperative Extension: https://secure.caes.uga.edu/extension/publications/files/pdf/C%201027-3_2.PDF
University of Massachusetts Extension: https://ag.umass.edu/sites/ag.umass.edu/files/fact-sheets/pdf/raised_beds.pdf
Oklahoma Cooperative Extension: https://humansciences.okstate.edu/fcs/ohce/site-files/trash/raised-bed-gardening-hla-6033web2015.pdf
Utah State University Cooperative Extension: https://digitalcommons.usu.edu/cgi/viewcontent.cgi?referer=https://search.yahoo.com/&httpsredir=1&article=2069&context=extension_curall
mnn: https://www.mnn.com/your-home/organic-farming-gardening/blogs/32-inspirational-gardening-quotes
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