The pros and cons of building raised garden beds from concrete blocks

Building raised garden beds has many benefits. Depending on how big you build them and your choices of materials, you can recoup the costs in just 1 to 4 years. They need less watering than planting directly into the ground and it is much easier to keep weeds and many pests out of a raised bed. For those (like me) with a bad back, raised garden beds are also much easier on your back and depending on how you build it, can be used as a temporary seat while working in the bed.

But cost to complete can vary greatly and there are many other factors to consider. In this article we will be looking at the pros and cons of using concrete blocks to build your bed. I will be writing additional articles on other materials in the near future. To keep cost comparisons as easy as possible I will try to keep all measures for cost purposes to 4-foot x 16 foot (outside dimensions)

Advantages of concrete block construction

1. Barring a natural or manmade disaster, they will last pretty much forever. This is a biggie in budget considerations.
2. Higher side walls have greater stability that many other materials.
3. You can add flat rocks or make your own fake rocks with molds available online, that are very aesthetically pleasing. This will add to your costs of course.
4. Unless you choose to add a topper block to your bed, you can use the holes within each block to grow herbs around your garden. Choosing herbs that provide some benefit to what you are planting can help keep pests from the garden while being a source of herbs to use in cooking.

Disadvantages of concrete block construction

1. Without adding a decorative over layer, some people consider them to not be aesthetically pleasing.
2. In some areas there are laws against having cement blocks showing in any construct on the property. Check with your local officials before starting.
3. Unless you have worked with concrete blocks in the past, there is a little bit of a learning curve, but most anyone can do it if they do a little reading before they start. It may however take a little more time to complete than some other materials.

Labor costs can vary greatly depending on your area and how many friends and family members you can get to help out. For that reason, we will not be including labor costs in our numbers. The project can be completed by the home owner to save some money.

A standard concrete block in the USA measures 16-inch-long, 8 inches high and 8 inches wide. We are building our bed 16 feet long x 4 feet wide. Each layer high we choose to build will be 8 inches. For most people 16 inches will be perfectly fine. If you have a bad back you might want to double that which of course would double your material costs. It is a decision you will need to make for your personal situation.

Let’s do the math to determine how many blocks we need per layer. Since our sides are 16 feet long and our blocks at 16 inches long, it is easy to know we need 10 blocks per side for a total of 20 blocks per layer.

For the ends we need we need 4 blocks per end. Keep in mind, the blocks are much wider than wood, so the inside dimensions will be only 3 feet. If you want that extra 12 inches in width, simply add 1 additional block per end and you will have the entire 4-foot width inside. So, we need a total of 10 blocks per layer for the ends.

Each layer of our bed will need 30 blocks. I would build a minimum of 2 layers high but if you choose you can build an 8-inch-high bed with only one layer.

My local Home Depot sells the blocks for $1.22 each. That means a 2-layer high bed would cost 60 x $1.22 = $73.20 plus tax for the blocks. You will also need Mason Mix to glue the block together. Home Depot sells it for $6.45 per bag. The number of bags needed will vary depending on how much you use between the blocks, but 4 bags should be plenty for the project making the cost just $25.80. The total so far is $99 plus tax.

Decision Time

Depending on where you live, this could be the only material costs. That would of course mean your bed would retain the look of concrete block. If you want something a little fancier, you will need to cover the outside of your bed. There are many ways to do this.

1. Paint – Many community gardens choose to use blocks because they rarely need to be replaced and are very cheap. Volunteers then paint bright colorful scenes on all sides creating a happy environment. You could also choose to simply paint the blocks in a solid color. This would add only the cost of the paint which can vary from $25 a gallon to $50 a gallon or more.
2. Stucco is a surface treatment that can add a more pleasing style to your blocks. It comes in many colors and costs range between about $16 to $35 per bag. Make sure you compute the square footage of the outside area of your bed so you can determine how much you will need to buy. The one drawback with Stucco is you may need to hire someone to put it on so be sure to figure their pay into your costs if you need to hire an installer.
3. Rock – This can be a beautiful choice and depending on your choice of rock can provide an upscale or a rustic look. Cost can be a major drawback as rock is fairly expensive and usually requires hiring a contractor to install it. To save some money, there are molds you can buy online that allow you to use concrete mixed with a colorant to make very realistic looks rock.
4. Adding a topper – To achieve a more finished look, you may choose to add a topper to your bed. There is a wide variety of choices but it can be a major addition to costs. Check with your local supplier to determine the best choice for the look you are seeking to obtain. There are concrete versions that are relative inexpensive with materials such as marble at the higher end.

That is the basics of what you can do with concrete blocks. In my mind, the biggest advantage is the fact your garden bed will probably last longer than your lifetime (and perhaps your children’s lifetimes too). Wood will need to be replaced at least every 8 to 10 years and perhaps sooner in areas with poor drainage or higher rainfall totals.
I hope you find this useful in your decision-making process. If so, would you please consider giving me an upvote and/or resteem.

Remember: Freshly grown food is cheaper, of higher quality and can keep your family fed if supply chains break down for any reason.