Think your veg garden needs a lift? RHS expert Leigh Hunt shares tips on when raised beds are useful
Growing vegetables in raised beds makes me feel like I’m a good gardener. When I glance across the plot, everything appears to be orderly and that subliminally tells me I’m on top of my veg growing game.
That’s often a lie, of course. But even if the carrots are measly and the fennel doesn’t bulb, I’m soothed by the neat patterns.
There’s even some published science behind this which suggests that the brain looks for patterns where none exist. So at least I’m predictable, if not always reasoned.
The rise of raised beds has been phenomenal in the last 30 years. Once they were largely championed at places like the RHS Chelsea Flower Show as an aid to reduce bending down and improve access for all.
By the 1990s, when the Ground Force era of TV garden makeovers was in full swing, these wooden structures had become a designer choice. And it’s this mix of ideas that raised beds are stylish yet practical which has made them a mainstayfeature in our veg plots.
Do I need raised beds?
Like a lot of garden features, whether you actually need them is another matter. It may come as a shock, but you can grow vegetables just as well in the ground as a raised bed. Rhetoric I know.
What makes vegetables grow is good soil (plus moisture and sunshine). You can have good soil in the ground and good soil in raised beds.
The only time where raised beds are really needed is where the garden soil is waterlogged. By lifting the soil above ground level it will drain and that’s great for permanent crops (such as rhubarb and asparagus) that would otherwise rot in the winter wet.
This also highlights that a wooden frame that contains soil at the same level as the surrounding ground is not a raised bed; and so doesn’t bring these benefits. However, it still looks nicely edged.
If you make a raised bed, you will have to put in more soil to raise the soil level. This leads to those two key questions: what and where from? It is best to fill the bed mainlywith soilas it doesn’t break down and slump in a few seasons (unlikegarden compost or potting compost).
I’ve pinched soil from borders around the garden and just enriched it with a couple of bucketfuls of manure per square metre. Bagged topsoil is good too; just expensive.
What about the cost?
Talking of expense, the price of timber edging has gone through the roof in the last couple of years. However, I’ve found my local recycling centre has a timber shop and they sometimes have ‘pallet collars’.
These four hinged boards are ready made frames that can be stacked to make taller beds. Just apply a water-based wood preservative to make then longer lasting. Alternatively, new sleepers and treated wood don’t contain the nasty chemicals of old so are fine for edible crops – and if you want to be extra cautious you can line with plastic (but this isn’t as desirable as we move away from using plastics too).
My last tip/warning is that raised beds dry out quicker than soil at ground level, so you’ll want to install some water buttsat the same time to catch and reuse rainwater this summer. Add to this some summer sunshine and the crops in my orderly raised beds can’t fail to please.
Happy growing!
| About the author
Leigh Hunt is aPrincipal Horticultural Advisor at the RHS and tends a veg patch in his other role of Head Gardener at a private garden. At the RHS, he tackles all the fascinating enquiriesfrom RHS members and is a specialist in the environmental benefits provided by plants. |
Pick of the crop
Look for the RHS Award of Garden Merit (AGM) when buying vegetable seed or small plants. You can also download the RHS lists of recommended cultivars.
FAQs
What Are 3 Common Mistakes to Avoid When Gardening with Raised Beds?
- Overcrowding Plants. One of the most common mistakes made when gardening with raised beds is overcrowding plants. ...
- Using Poor Quality Soil. Another common mistake when gardening with raised beds is using poor quality soil. ...
- Neglecting Watering and Drainage.
The cons of raised beds
The soil mix also can be a significant, albeit one-time, expense. Raised beds need water more often since the soil is more exposed to air and dries quicker. Similar to growing in containers, the extra watering can leach nutrients out of the soil quicker than in-ground gardens.
Should I put rocks in the bottom of my raised garden bed? ›
A: You should avoid putting rocks in the bottom of your garden bed. A common myth is that this will improve drainage. Instead, this can actually increase water saturation levels as well as allow gravel to mix in with your soil, which can prove very difficult to remove later on.
What is the easiest thing to grow in a raised bed? ›
What are some easy vegetables to grow in raised beds? While many vegetables thrive in raised beds, some particularly beginner-friendly choices include radishes, lettuce, bush beans, and kale. These plants are generally low-maintenance, have shorter growing seasons, or are less prone to common garden pests.
What not to fill a raised garden bed with? ›
Raised beds that are small and shallow (under 12 inches deep) are typically only filled with soil. Adding other organic materials to shallow beds usually isn't a good idea. Sticks, twigs, and other materials further reduce the limited soil space and can interfere with plant root growth and water drainage.
How deep should raised beds be? ›
They should have at least 8 inches of soil depth to accommodate the root systems of plants, because the majority of plant roots require 6 – 8 inches of soil for healthy root growth. A depth of 8 – 12 inches will suffice for most gardening situations.
What is the safest material for raised garden beds? ›
Untreated wood: Cedar and redwood are popular choices because they naturally resist rot and insects, and they do not need chemical treatments that could potentially harm your plants.
What do you put in the bottom of a raised garden bed? ›
Start with a layer of landscape fabric to prevent soil from washing out. Above this, a layer of gravel or small stones can aid in drainage. Then, fill the bed with a mix of topsoil, compost, and other organic matter. This layered approach ensures good drainage while providing a nutrient-rich environment for plants.
What is the best base for a raised bed? ›
Newspaper or Cardboard
Even simple, cheap materials can block weed growth from below your garden beds. You can simply lay them on the ground before setting your garden beds on top of them.
How many years do raised beds last? ›
Building a Raised Bed from Lumber
Pine and other framing lumber will last about 4 to 5 years, while more expensive cedar will hang together for 8 to 10 years. Don't use redwood, which is an endangered species.
You can line the bottom of your raised garden bed with cardboard and newspaper to block out weeds or act as a barrier against rhizomatous, weedy or invasive plants. While some may opt for landscape fabric, cardboard is a more cost-effective option.
Should you put landscape fabric under a raised bed? ›
The fact is, landscape fabric is not a necessity if say, you want to control weeds because the confined space makes it easier to control weeds. But, you can use landscape fabric as a raised bed liner for other reasons, such as preventing soil erosion or improving the life of the raised bed itself.
How many bags of soil do I need for a 4x8 raised bed? ›
For a 4x8-foot raised bed with a 6” height, using Mel's Mix: about 5 cubic feet each of compost, peat moss, and vermiculite is needed. It usually takes about two to three bags of purchased fertile mix (1.5 cubic feet each) to cover the bed surface to a depth of 2 inches.
What vegetables can survive in a raised bed? ›
Root vegetables—radishes, carrots, turnips, onions, shallots, garlic—grow best in loose, partially sandy soil, which makes them ideal candidates for raised beds, where the soil is usually much less compacted in the absence of foot traffic.
Can I plant squash and cucumbers in the same raised bed? ›
Additionally, squash can be a heavy feeder, which means it may compete with cucumbers for nutrients. Onions and beans are not good companions in the garden.
Growing vegetables in raised beds makes me feel like I’m a good gardener. When I glance across the plot, everything appears to be orderly and that subliminally tells me I’m on top of my veg growing game.
Do I need raised beds?
What about the cost?
Pick of the crop