Many people are growing vegetables in their backyards for the first time; food prices are likely forcing some to start.
You don’t have to look far to find information on raised garden beds and how good they are, but getting set up with them can be expensive for beginners.
The cost is just one of many disadvantages of raised garden beds. We use corrugated raised beds, and we believe people should have both sides before jumping in and spending a heap on garden beds.
Why would raised garden beds be a bad thing?
In some situations, raised garden beds can be considered a wrong choice, but it’s a stretch to call them bad.
Raised beds can be considered a wrong choice if the costs outweigh the benefits in a given situation where the natural ground is entirely satisfactory for growing vegetables. In all other cases, we consider these beds great investments, as discussed in “Metal raised garden beds: are they a good investment? “
We are in a location where the soil is based more on a fungal system than a bacterial one. This hampers our ability to grow some vegetables, so we decided to use raised garden beds.
The raised garden beds allow us to fine-tune the soil inside the beds and keep the problematic soil conditions at bay.
In a different scenario, the ground soil may be perfect for the types of growing we wish to undertake. Using raised garden beds in this situation could be considered a wrong choice, especially if the raised beds cost a lot.
The only benefit we can see in this scenario is it can aid someone with a bad back or a similar issue, and the extra height can be beneficial.
Are raised garden beds better than planting in the ground?
In some circumstances, they are, and we detail these below. Every location will have potential site-specific problems, and each situation should be considered individually.
The requirements for organic growing may dictate that the garden beds must be raised to ensure clean soil. Below is a list of the pros and cons of raised garden beds. Some or many will be relevant to every location.
What are the pros and cons of gardening with raised garden beds?
Every garden location has good things about it and bad things to consider as well. The gardeners’ job is to determine what issues need to be addressed and what can be lived with. The lists below can help with some direction.
What are some advantages of raised garden beds?
- It is easy to improve the soil
- They are great on rocky ground.
- They can allow you to grow over a high water table area.
- They can limit nutrient loss from sloping land.
- They are great over contaminated soils.
- There is less bending over as you garden.
- Better weed control.
- Far less risk of compacted soils.
- Far less chance of invasive tree roots.
1. Soil Improvement
This is where raised garden beds shine because they allow us to dedicate a particular garden bed to a specific soil type. This enables us to expand the plant varieties that would typically be more problematic to grow.
This is all to do with soil structure and pH. A single bed can be dedicated to plants that grow best in acidic soils, while other raised beds can have more neutral soils.
2. Rocky ground.
This is another situation where raised beds can be a significant benefit. Placing a raised garden bed on a concrete slab is possible, so the rocky ground is no reason to not grow your own food.
Some people may face difficulty leveling the ground where the raised bed will rest, but with some work, the raised beds can sit on just about anywhere you want.
3. High water tables.
Some areas have a water table below the surface in wet seasons, which usually falls away after the drier seasons get underway. These situations can be painful when the soil becomes waterlogged, and your gardens are at ground level.
During the extended wet season here where we live, we have seen the water table rise to 1 ft below the surface, creating havoc with plants that have their roots down that far. Because our wet season can run for several months, it can be the reason for plant losses.
Raised garden beds get us out of this situation, and they allow the soil to drain freely, but there is a downside to this with raised garden beds that we will discuss below.
4. Nutrient loss.
If there is any slope to your block of land where you live, you will have nutrient flow across the surface during heavy rainfall.
Suppose your property has been designed to work with this nutrient movement. It can be seen as a trash line from a flood event. In that case, you may have already put in place systems that can harvest and benefit from the nutrients’ new location.
This visual material collected against a fence line or a tree base is seen once the water recedes.
The nutrient loss will slow your garden down. It can be something as simple as your compost being washed away or any organic fertilizers that have been spread.
Raised garden beds can limit nutrient loss because they are likely above water and hold the nutrients inside the bed. The soil can drain excess moisture once the heavy rain has passed, and the plants can continue flourishing.
5. Contaminated soils.
This is a direct benefit. There are many locations around the world where past generations have happily used extremely damaging chemicals, and these still have residual amounts in the soils where many of us live.
The world is becoming better educated about the dangers these chemicals present, so raised garden beds are the best way to grow your own food on top of the suspect ground.
This raises a new question on how to be sure that the soil you use to fill your raised beds is ok to grow food in, and this is a situation many of us face.
Everyone gets old, and bending down to the ground level for extended periods can get stale quickly.
Raised garden beds help those of us who are getting on in years to still be able to effectively grow food from a more generous height than the ground-level garden bed.
Once the garden beds are in place, there is no reason why you cannot be an active gardener well into your twilight years. This is some time away for us here, but we are all prepared.
7. Better weed control.
Sometimes weeds get out of control and set seeds that are certain to spread.
The ground-level garden is predisposed to collecting these seeds, where they inevitably germinate and take up space and nutrients that could otherwise be allocated to a few more vegetables.
The raised garden won’t eliminate weeds, as the wind can lift the seeds into your garden beds; however, this is less of a problem when compared to the ground-level gardens.
8. Soil compaction.
Soil compaction happens when we walk over a garden bed, creating unfavorable conditions for some vegetables. In severe cases, it can create anaerobic soil conditions that will stop healthy plant growth.
The raised garden bed is a great way to stop this compaction. Machinery causes a lot of soil compression, and because the raised beds are up off the ground, mechanical compaction is less likely to occur.
9. Invasive tree roots.
Some trees have wandering roots and can take over ground-level garden beds in some cases. While a raised garden bed cannot prevent the roots if they are in the area, it is less likely they will be a problem.
What are the disadvantages of raised garden beds?
- Side walls can hold heat and kill soil biology near the garden wall.
- They can be expensive to buy or build.
- The garden needs hand digging.
- There are a few skills required to construct a garden bed.
- The location needs to be accurate because they are hard to relocate once complete.
- Some materials rot quickly.
- Far more frequent watering is required.
1. Hot Walls
The walls of a raised garden bed can get hot. In our location, the winter sun is to our north, and the sun is 48 degrees altitude at midday.
This means the sun hits the garden bed walls at a 45-degree angle(thereabouts) during the day’s heat.
We have all our beds running east-west at length, so the widest part of these garden beds is hit by the sun. This is intentional to capture the most sunlight during our winter months. However, it should be noted our winters are not like the winters most people enjoy.
It rarely gets below 10C (50 F), and the midday temperatures get to 26C (75F), so this is the type of heat the sides of our garden beds face daily. “Using raised garden beds, 6 questions answered” is recommended for further info.
From experience, we know that the hottest side of our beds struggles to retain moisture, and they are not the best location for the soil biology that we try to encourage. Our raised garden beds are all corrugated Metal and are close to 750mm high (30 inches).
We are aware of the temperature problems in the soil profile, so we work around them where we can, and it is an ongoing process.
We work with soil biology to grow our food; this is a part of the self-sufficient food garden methods we find very enjoyable and educational. To harm the little critters that live in our soil seems backward to us. We pay in the end through less food.
It is safe to say that raised garden beds are expensive. We paid about AUD 350 per garden bed, which is about USD 250 in late 2021.
We have 9 beds with a single smaller size making up the tenth. These garden beds have paid for themselves in produce over a few seasons, but the upfront costs can be high.
The soil needs to be purchased for some people. Considering that each garden bed can take up to a cubic meter or yard of soil, the costs start to climb pretty high damn fast. Still, we were fortunate that we had soil available on site from a pool excavation about 15 years ago.
This is just for the subsoil layers and does not consider the topsoil costs. Fill soil can be upwards of $55usd per cubic yard, then the top soil costs can be double that. If you are interested in making your own soil, “What is the best soil for organic gardening in raised beds?” is recommended as a read.
3. Hand tilling.
Raised garden beds are not your thing if you like to till the soil with rotary hoes and similar tools. Because of the height of the typical raised bed, you will likely be hand-digging the soil each season.
This can be an enjoyable form of exercise for many of us. Still, some of us have health issues that can be affected by manual labor, like extensive work with a garden fork.
This tilling is often done after a growing season and is part of “How to maintain organic soil in raised garden beds.” This post describes how we go about it.
4. Skills required.
Suppose the metal garden beds are unavailable in your area, and you have access to lumber. In that case, considering building your own can be a good idea. You should be up to speed with a few required skills.
Power tools and the know-how to use them safely are skills that will help enormously, and if you do not possess these abilities, maybe you know someone who does, and they can step in to fill the gaps for you.
There are several materials you can use to build a raised garden bed, and “What is the safest material for organic raised bed gardening?” details some of them.
5. Lack of mobility.
Once these raised beds are in place, they aren’t often moved about. They can be considered permanent, so the planning needs to be done before the placement.
If you have a few of these beds, it can be a good idea to place them while still empty and leave them for a few days to see if they allow good movement in and around them.
Get the location wrong; it can be a lifetime of looking at that bed knowing it is wrong. Three of our garden beds are slightly different in size and sit not quite right in a row.
It was impossible to get them spot on and accurate, so we now have to live with them being where they are, all slightly crooked to each other. Some also have sharp top edges that we are slowly dealing with, as described in “Can edges on corrugated steel garden beds be made safe? “. This is recommended if kids are expected around your garden area.
Because of the initial costs of these garden beds, some of us get cheaper garden beds made from inferior materials.
These beds look great for the first few seasons but quickly deteriorate through rot and rust. Some of the cheaper materials can also have toxins that are residual effects of making those materials. Pressure treatment of pine wood is one such material.
The result is that the cheaper garden beds can become more expensive once they have to be replaced a few times. Hence, the initial high prices of the corrugated steel garden beds actually stack up in the end.
We have a dedicated post on “Why use corrugated steel raised garden beds?” for you to explore for further information.
7. Watering frequency.
In some situations, raised garden beds are claimed to have better drainage than natural ground gardens. This can be true if you know the soil types that the garden beds have been filled with.
The downside of this better drainage is that the raised garden beds typically require more watering, all because the soil drains better. This is a good thing sometimes, but if water is scarce where you live, this extra watering may not balance out effectively.
Some additives can help with water retention, but these end up adding to the overall costs of the raised garden beds.
As you can see above, the notion that raised garden beds are the be-all and end-all is just silly. There are benefits to these beds; however, there are disadvantages that should be acknowledged with raised garden beds.
How many of these affect you and your situation is totally on you to decide, and now you can make a more informed choice that can stand you in good stead for the years to come.
Article by Tim Blanch for TheTropicalHomestead.com. He is a qualified Permaculture designer.