Raised Garden Beds Next To House Foundations- Explained


Home gardening is one of the best ways to gain direct access to fresh organic produce (or grow beautiful decorative plants) while making the most of your yard space. However, some yards are smaller than others and, therefore, some homeowners may feel compelled to build their gardens right next to the house foundation.

Placing a raised garden or flower bed next to a house foundation can be done safely. Considering what water can do to erode a foundation, providing adequate space and drainage is a must. It is also important to consider the materials used, types of plants, and sunlight.

In this article I will focus on the feasibility of this type of gardening. We will address some key questions surrounding raised gardens and their proximity to the house. We will also point out the best bases you can use to set up your own fabulous garden. Let’s go!

Should I Build A Raised Garden Bed Next To My House Foundation?

There are several reasons why you would want to set up a raised garden bed. Maybe you just want to add a bit of pizzazz to your yard with a stylish bed. Or maybe you want to keep your precious vegetables out of the local vermin’s reach. Whatever your needs, a raised bed is seldom a wrong choice.

However, there is one major concern, though…the placement.

Where you choose to build your raised bed is of the utmost importance if you want your plants to grow strong and healthy. Building a garden bed takes a considerable effort, time, and resources, so due diligence is a must if you want to avoid waste.

I wouldn’t put a raised right against the foundation. Personally, I would have one 6 feet away from the house and a few feet apart from one another so you can maintain them.

Jerry McMillan, McMillan Lawn Service, 40 Years Experience, Great Grandpa

Setting up your raised garden next to your home’s foundation may seem like an efficient use of space, but you will need to consider a few things before you do this.

Firstly, does your chosen spot get ample sunlight? This may seem like a no-brainer, but still worth checking. Building one or more of these raised beds is quite a bit of work.

Since it is easy to overlook important issues at times until it is too late, make sure to check the amount of sunlight your particular set of plants need and locate your bed accordingly. Choosing a spot that is shaded by trees or an overhanging roof all day will prove problematic for your plants’ development. It’s best to check twice and build once.

The second consideration is whether the build will obstruct any weep holes at the base of your house wall. This mostly affects brick houses, which often feature moisture-draining openings called weep holes. 

Bricks, and the mortar that binds them, absorb water which can collect within a wall over time. If water continues to collect like this, the integrity of your wall may be severely compromised. Weep holes are tiny slits, or holes, at the base of the wall that allows all this moisture to seep out.

Placing your raised garden bed directly against the wall may obstruct some of these weep holes, which could accelerate damage to your wall. If your garden bed base is made of wood, constant exposure to weep hole moisture could lead to rot.

Another consideration is how water will drain from your bed. A house’s foundation is particularly vulnerable to long-term water damage. Failure to set up proper drainage will result in excess seepage to the foundation…and that is BAD news for you.

Again, you ought to leave a several-foot gap between your foundation and your garden bed. Not only will this eliminate the risk of water damage to your foundation, but it will also make it easier to maintain and clean all sides of the raised bed.

Can You Plant A Vegetable Garden Next To Your House?

While a flower bed can be planted pretty much anywhere, vegetables require a tad more care. 

Toxic chemicals are veggie enemy no.1, and by planting a garden right next to your house, you may be throwing your crops directly into the firing line. This is because some of the materials used to construct walls contain potentially harmful chemicals that could seep into your garden soil via leaching.

Concrete walls, for example, have traces of calcium oxide and chromium. The former is known for its acid-like effects on human tissue, while the latter is a common allergen for some people. Older timber walls also present a potential threat.

Before 2004 some lumber used chemicals to treat the wood that could contain trace amounts chromium, copper, and even arsenic! Though lumber today is extremely safe for gardens, you may not know every type of material in your home.

If these chemicals leach into your garden, vegetables would more than likely not be affected or become toxic themselves. Since you are planting fruit and vegetable plants next to your home foundation in this scenario, you would need to know the chemical composition of your walls just to be safe.

If you house contains any wood for instance older than 2004, it should be tested before soil growing food products is placed nearer than 6-10 feet.

Again, this is a very miniscule danger in the short run and only a small one after many years of high levels of exposure, but when your health is involved, older wood treated with these chemicals and metals should be avoided.

Gutter water can also carry toxins from the roof. This is especially true if you have an asbestos roof. Many roof tiles have petroleum products in their makeup and these can easily make their way into the soil of raised gardens placed near house foundations.

Gutter water can also fall violently and excessively on your vegetables, which could cause physical damage.

In addition, placing a raised garden bed, specifically, right next to your wall could give pests a way to access your vegetables or vice versa. Pests could use the raised garden to gain access to your house walls and foundation.

Where Is The Best Place To Put A Raised Vegetable Garden Bed?

The best position for your raised garden will be unique to the nature of your environment and yard.

Sunlight is a major factor, and most plants require at least 5-7 hours of direct exposure to meet their daily nutritional needs. Avoid placing the bed in an excessively shady area.

Next is drainage. You want a position where drained water will not cause damage. The issue of drainage is why you should think twice about planting right next to your house’s foundation.

Air circulation is another important one, especially in hotter climes. Plants, just like animals, respire and undergo gaseous exchange (“breathing”), so your chosen spot should facilitate that.

For your convenience, your garden bed should be placed close to your watering source, tools, and other supplies. It is also wise to ensure direct access for a wheelbarrow if need be. 

Which Side Of The House Is Best For The Garden Bed?

If you must set up your garden directly next to your house, you should ensure you know the answer to the following:

  • Which side has maximum sunlight?
  • Which side is close to the water source?
  • Is there a side sure to have no toxic wall materials used?
  • Is there good air circulation?
  • Do you have a spot away from gutter water drainage?
  • Is the area accessible with heavy tools and supplies?
  • Are you able to provide easy access for maintenance?
  • Do you have or can you create level ground?

What Base Should I Use For A Raised Garden Bed?

You can use any number of materials for your raised garden’s base. Each has its benefits and limitations.

Wood For Raised Garden Beds

Wood is a popular choice for most people. Cedarwood is sought specifically for its durability, aesthetic qualities, and its resistance to damp and humid environments. Cedarwood also contains a chemical compound known as thujone, which is a repellent for a lot of insects.

I wouldn’t use railroad ties because of the creosol in them. I would use treated wood though and possibly put plastic down the sides so the wood would stay drier. I wouldn’t put anything on the bottom, but would add good soil.

Jerry McMillan, McMillan Lawn Service, 40 Years Experience, Great Grandpa

Some using anecdotal evidence may decry the use of pressure treated lumber on raised beds due to a leeching effect of copper used to treat the wood into the soil.

This would be based on incomplete or outdated data.

Actually, Jerry is right in advising treated lumber. In many university studies like the one done by researchers at Oregon State University, the amount of copper leeching that can occur from this lumber into some soils is not at levels harmful to adults or children as related to the plants grown in the raised bed.

Furthermore, the area of leeching is localized to small amounts of soil near the wood.

Using a plastic sheeting as Jerry suggested as a liner not only will allow the wood to last longer, but it will also cut out 99% of the copper leeching that could occur in the first few months.

With the copper levels posing no risk in the first place, using pressure treated lumber for raised garden beds is a good option.

As for the arsenic levels that could be found in pre 2004 examples of pressure treated lumber, according to studies conducted by Penn State University, “It is virtually impossible, however, for a person to eat enough vegetables to contract acute toxicity from any of these metals.”

With that being said, this is not an issue today. Arsenic has not been used in pressure treated lumber since 2004 in the United States.

According to studies done by the EPA, though safe levels of copper could be measured from outdoor applications of newer forms of treated lumber, even this became unmeasurable after two months time.

Of course, sooner or later, wood is bound to rot. This decomposition will be faster if you live in wet areas. Ultimately, if you choose wood, you should know that you will have to replace it someday.

Metal For Raised Garden Beds

If you want something a little more permanent, you could opt for a metal base. However, you cannot just use any type of metal. Remember the toxicity issue we discussed above? A lot of metals are even worse.

The best metal to use for your raised garden base is galvanized steel. Like wood, galvanized steel is pretty affordable. However, unlike wood, it is impervious to the elements and will not be affected by damp. It does not rust, it is non-toxic, and requires almost zero maintenance. You will never have to replace a steel base.

As far as drawbacks, galvanized steel has very few. Some people may not like the look of a steel garden base as much as a wooden one.

Other useful materials for building a raised garden include:

  • Bricks
  • Rocks
  • Cinderblocks
  • Mesh wire fencing

The Final Touches On Raised Garden Beds Near A House Foundation…

So, is it safe to put a raised bed near the foundation of a house? Yes and no.

If it is your only option then there are steps to take that ensure the safety of your foundation due to water and insect damage. There are also steps to take in order to ensure runoff from roof tiles and other sources don’t contaminate your plants or produce.

As Jerry suggested, it is advisable to at least have a 6 foot distance between the raised garden and a house foundation. This cuts down on drainage into and out of the bed being an issue, allows for better sunlight options, and gives room on all sides for maintenance.

Hopefully we have given you some food for thought (pun intended) and aided your decision on whether a raised bed is right to put next to your house foundation.

Other References

https://www.gardensalive.com/product/ybyg-how-close-can-you-plant-next-to-a-house

https://gardenersyards.com/should-i-build-raised-garden-bed-against-house-pros-cons/

https://www.youtube.com/watch?v=7cPi3ixNF-Y&ab_channel=GardenerScott

Mathew Booe

Mathew has worked in landscaping professionally for over 10 years. He is a grandpa and frequently interviews other experienced landscapers and lawn care experts who are also grandpas for these articles.

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