It’s time for planting, you are looking to expand your garden or maybe you are just getting started and you want some raised beds. Getting everything you need and figuring out the steps involved can be a bit daunting, especially when costs start creeping in.
Throughout my gardening journey I’ve used raised beds to grow a ton of veggies. Drawing from my experience, I’m eager to give you my top tips on raised bed gardening, including some key considerations and the best methods for filling them.
Raised Garden Bed Height Considerations
Before we get into filling the beds there are a few things we want to consider that will influence the height of your beds.
Climate
- Dry Climates: Raised beds dry out faster in hotter, drier climates, requiring more frequent watering. Adding clay to the soil can help retain moisture.
- Cold Climates: Raised beds are susceptible to frost heaving in colder climates. Insulate beds with mulch or cover them in winter to maintain soil temperature and protect plants from frost.
Soil Conditions
- Rocky or Sandy Soil: Raised beds can be used when you have rocky or sandy soil, providing a place to start fresh and add nutrient dense soil.
- Heavy Clay Soil: Clay soil tends to become too soggy in wet conditions. Adding height with a raised bed allows for better drainage and aeration.
Plant Requirements
A general depth of 30 cm (12 inches) is fine for most plants, but root vegetables like carrots or potatoes may require deeper beds of 60 cm (24 inches) to give provide enough room for their root systems and tubers.
Ergonomics
Taller raised beds reduce strain on gardeners by minimizing bending and stooping, providing a more comfortable and enjoyable gardening experience. Think about age, fitness, and health concerns when determining how high a raised bed should be..
Pest and Weed Control
Taller beds deter certain insects and rodents due to their elevated height, making access more difficult. Additionally, raised beds help minimize weed pressure, particularly effective against low-creeping weeds.
Raised Bed Garden Layout and Ideas
Creating an effective garden layout is essential for maximizing space, promoting healthy plant growth, and achieving a good harvest.
Sunlight Requirements
- Sunlight is crucial for plant growth, preventing disease and increasing productivity in raised bed gardening.
- Aim for 6-8 hours of direct sun exposure for the best harvests.
- Consider year-round sun exposure, the sun will move around your yard depending on the time of year.
- Face beds north-south for consistent sunlight, but be aware of tall plants or structures creating shade.
What Size Should My Raised Bed Be?
- Best width for raised beds is around 60cm (2ft) for easy access. You want to be able to reach at least the middle of the bed.
- Larger beds, like 1m square beds (11 ft²), accommodate larger plants but may require careful management.
- Consider splitting larger beds with a trellis for efficient space use and access.
Personal Note: I find these standard-sized beds easier to work and move around with, but consider different shapes and lengths to fit your yard.
Square Foot Gardening
- Square foot gardening maximizes space by dividing beds into square feet.
- Each square foot can accommodate specific vegetables, allowing for efficient planting.
- Square foot garden provides a flexible and modular system for various garden layouts.
Raised Bed Construction Materials
Raised beds are made from various materials each with their own pros and cons. Whichever you choose keep in mind to avoid chemically treated materials that may impact the soil and your health. It’s good practice to educate yourself what chemicals are used in your garden bed materials.
Wood
Pros:
- Depending on your location, wood can be relatively cheap, especially if sourced locally.
- Hardwoods are more resistant to decay, though they may be more expensive.
- If you’re handy, wood can be customized to fit various shapes and sizes.
Cons:
- Susceptible to insects, such as termites.
- Prone to decay over time, especially if untreated or exposed to moisture.
- Often treated with chemicals to resist decay and insects, which can be a concern.
- Not as UV resistant as other materials making it less durable in harsh sun conditions.
Metal
Pros:
- Usually comes in easy-to-assemble kits.
- UV-stabilized metal is suitable for climates with harsh sun exposure.
- Provides a modern aesthetic and can complement various garden styles.
- Absorbs heat, making it beneficial for prolonging the growing season in colder environments.
Cons:
- Tends to rust over time, especially in humid or coastal environments.
- Initial cost may be higher compared to other materials, particularly for larger beds.
- Limited customization options compared to wood.
- May heat up in hot weather, potentially drying out beds.
Brick
Pros:
- Highly resistant to weather and durable, offering long-term stability.
- Immune to insects and pests.
- Relatively affordable, especially if sourced locally .
- Absorbs heat, making it beneficial for prolonging the growing season in colder environments.
Cons:
- Heavy to work with.
- May heat up in hot weather, potentially drying out beds.
- Unstable unless cemented together
Composite Materials
Pros:
- Made from recycled materials, offering an environmentally friendly option.
- Durable and resistant to decay, without the risk of chemical leaching associated with treated wood.
- Low maintenance and long-lasting.
- Lightweight and easy to work with.
Cons:
- Cost may be higher compared to some other materials.
- Appearance may not be as natural as wood or brick.
Concrete Blocks or Cinderblocks
Pros:
- Durable and long-lasting.
- Readily available and relatively inexpensive, especially if obtained locally or second-hand.
- Can be stacked easily to achieve the desired height for raised beds.
- Absorbs heat, making it beneficial for prolonging the growing season in colder environments.
Cons:
- Heavy
- Some blocks may contain additives or chemicals that could leach into the soil.
- May heat up in hot weather, potentially drying out beds.
Budget Friendly Options
If you are just starting out or want to keep costs low, you don’t have to invest in fancy new beds or purchase expensive construction materials. From the materials listed above, many can be sourced cheaply or for free!
Budget Construction Material
Look around online marketplaces where you can often purchase second-hand beds cheaply or even get them for free if you take the soil as well. Additionally, people often give away free construction materials like old bricks and pavers, and you might already have scrap wood or rocks lying around your yard that you can use.
Budget Fill Material
- If buying soil order in bulk rather than using bags if you are filling a lot of beds to save on costs.
- It’s ok to use cheap compost or potting mix as the bed will be full of nutrients as the materials break down.
- Use kitchen scraps, leaves or yard trimmings from your yard or neighbours.
- Horse stables often give away manure for free if you ask, just be careful of residual pest treatments in the manure. Find out when the horse was last treated and with what and follow the pesticide’s manufacturer guidelines.
Personal Note: I use UV stabilized metal beds due to their ease of construction and longevity. While they tend to rust over time, in my experience, they are more durable than wood in my conditions.
Filling Your Raised Bed with Hügelkultur and Lasagne Gardening Techniques
When it comes time to fill your beds I recommend the same method I always use which is a mix of Lasagne gardening and Hügelkultur.
Hügelkultur
Hügelkultur or hill culture is a method of growing food by building mounds and planting into the side of them. Large woody materials such as logs form the base and as you go up a layer smaller things such as branches, leaves and eventually soil is added. The mound structure helps with water retention, promotes soil aeration, and provides nutrients as the organic matter decomposes over time.
Lasagne Gardening
Lasagne Gardening, also known as Sheet Mulching, shares similarities with Hügelkultur in its approach to building raised beds. However, rather than relying heavily on large woody materials as in Hügelkultur, Lasagne Gardening focuses on layering organic materials such as grass clippings, leaves, kitchen scraps, newspaper, and cardboard in a balanced blend of nitrogen-rich (green) and carbon-rich (brown) materials.
As these layers break down over time, they create nutrient-rich soil, offering a sustainable and low-maintenance method for gardeners to improve soil quality and fertility.
Personal Note: I use the fundamental idea of these models to fill my raised beds. Don’t worry too much about layering it all perfectly and don’t think about carbon/nitrogen ratios, just use these models as a rough guideline.
Layering A Raised Bed
Step 1: Lay a Base layer
If you are starting on top of a lawn, it can be a good idea to place weed mat or cardboard on the bottom of the bed to suppress anything from growing up into the bed. This largely depends on the kinds of weeds and grasses in your area but cardboard on the bottom never hurt anybody.
You then put down large woody or leafy material which will take longer to decompose and during that time provide habitat for fungi, bacteria, and insects. It will also serve to hold moisture and nutrients. I like to use logs, large branches and palm trimmings, anything that will take a long time to decompose and provides a lot of mass.
Step 2: Add a Middle layer
I just fill this with smaller materials such as sticks, leaves, grass clippings, kitchen scraps, basically anything have on hand that you would normally use for composting. Compact it down a little to make room for the final layer of soil on top.
Step 3: Add a Top layer
This layer is where you are going to plant, keeping in mind what you are planting as some need more depth than others, as we mentioned before, a good depth is 30cm(12inches) of soil to plant in. You can use old potting mix, ready compost or garden soil on the top layer. A combination of gagged soil and compost is generally an easy and clean way to fill a few beds.
I find planting straight away to be fine, some people like to wait for the materials to decompose before planting. This is highly dependent on what materials you used on the top layer in my experience, if it’s more raw manure or not ready compost then you may benefit from waiting a few weeks before planting into the top layer.
You can expect your bed to sink as the materials in the lower layers break down. Just top it up with more compost/soil every growing season.
Conclusion
Raised bed gardening offers a lot of benefits, including better soil conditions, pest control, and accessibility. By choosing the right bed height, materials, and planting techniques, you can create a productive and enjoyable garden. Sustainable methods like Hügelkultur and Lasagne gardening improve your soil at low cost and in an environmentally friendly way.
How do you fill your raised beds, and what materials do you use? Share your tips and experiences in the comments below.
