Gardening with raised beds is my preferred method. When you’re doing raised bed gardening, you can control your soil type easily. Your beds warm up faster in the spring. You’ll have less weeds and an easier time clearing out those which do appear. The soil doesn’t become compacted like an in-ground bed. But there’s one drawback: you have to figure out how to fill a tall raised garden bed. And that seems daunting!
Whether you’re using native soil or a soil mix, a blend of soil and compost, or something else, we’ll go over your options. There’s plenty of things you can do to fill your gardens raised beds!
Raised garden beds are becoming increasingly popular for home gardeners. They provide better drainage allow you to control the soil quality reduce weed problems, and make gardening accessible for people with disabilities or bad backs.
However many gardeners are hesitant to try raised beds because they worry about how to fill them, especially the taller styles. Filling a 2-3 foot tall raised bed seems like a daunting task.
But having the right information makes it easy to fill tall raised beds properly. In this complete guide, we’ll walk through everything you need to know, from planning your bed, choosing fill materials, and layering for success.
Factors That Determine How to Fill Your Raised Bed
There are a few key factors that impact how you’ll fill your tall raised garden bed:
1. Height of the Bed
The taller the bed, the more soil you need. For example, a bed that is 2 feet tall and 4×4 feet will need about 1.5 cubic yards of soil. The deeper the bed, the more you may want to use filler or bottom layers to save on soil costs.
2. Drainage
Make sure the base allows for drainage by using gravel or placing some bricks under the corners Avoid rocks or broken pottery, as these can create a perched water table
3. Type of Plants
Root crops like carrots need deeper beds filled with quality soil. Shallow-rooted plants like lettuce do fine with just 6 inches of good soil.
4. Climate
In rainy climates, improve drainage. In hot, dry areas focus on moisture retention.
Filling the Bottom of the Bed
For the bottom 4-8 inches of a very tall raised bed, inexpensive fillers can be used in place of expensive soil mixes. This saves money while still providing plenty of root depth. Materials that make good fillers include:
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Crushed gravel or pea gravel for drainage. Use a 1/4-1/2 inch layer.
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Wood chips, small logs, twigs, or bark. Provides aeration as it decomposes slowly.
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Leaves, straw, hay, shredded newspaper. Readily available carbon sources that break down over time.
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Compost or manure. Nutrient sources that continue decomposing.
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Landscape fabric (optional) to block weeds.
Avoid rocks, broken pottery, concrete chunks, or anything that could impede drainage. The bottom layer simply needs to allow for water flow.
Creating the Main Soil Layer
The top 12-18 inches should be high quality soil mix for the plant roots to thrive in. Here are common options:
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Blended native soil from the garden
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Bagged topsoil or triple mix blends
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A mix of compost and soil such as equal parts quality compost and topsoil
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Peat or coir based soilless mixes (good drainage but expensive)
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Custom mixes such as equal parts compost, peat moss, and vermiculite
The soil blend needs to be loose, nutrient-rich, and hold moisture well. Enhance drainage as needed by adding perlite, rice hulls, or pine bark fines.
For vegetable gardens, extra compost provides nutrients. Local soil balanced with compost is an economical choice.
Layering Materials in Sequence
When filling the bed, layer materials from bottom to top in this order:
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Gravel base for drainage
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Lower filler layer such as wood chips, optional landscape fabric
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Main soil mix
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2-3 inch layer of compost or aged manure (optional)
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Layer of mulch such as wood chips or straw to retain moisture
Build your layers in sequence, watering each one to settle materials before adding the next. The mulch layer can be refreshed annually as it decomposes.
Filling Tips and Tricks
Follow these tips when filling your tall raised garden beds:
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Gradually blend bottom layers into native soil so water flows between them
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Slope soil gently outward from the center for drainage
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Use a soil calculator to estimate how much of each material you need
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Fill beds in fall and let overwinter before planting
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Top off beds each year with 1-2 inches of compost
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Mulch annually with leaves, wood chips or straw
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Don’t line beds with landscape fabric (it actually causes rot)
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Make sure tall beds are secured well to prevent tipping
Filling a tall raised garden bed is easy when you follow this layered approach. With the right materials and sequence, you’ll have a successful garden bed that offers healthy root zones.
The key is using high quality soil, compost, or soilless mix for the top layer where most plant roots grow. Fill the bottom portion with inexpensive organic materials to save money. And always focus on enhancing drainage and nutrient levels based on your specific climate and plants.
Following these steps to properly fill your tall raised beds will lead to productive gardens! Just take it layer-by-layer and soon you will have wonderfully rich soil to grow thriving vegetables and flowers in.
What’s Your Bed For?
Before you begin to plan, you’ll need to decide what your bed’s actually used for. After all, some plants are more shallow-rooted than other plants. As an example, your average red radish is going to require very little depth, where a daikon radish requires a couple feet of soil.
If you have an idea of the root depth you’ll be growing in each container, you can customize your fill materials to that. For instance, someone who’s going to have a devoted leafy greens bed only needs 6-8″ of high-quality soil on the surface. Native soil or other materials can be used beneath that to prove bulk. But someone growing carrots will want at least a foot and a half of quality soil.
Drought-tolerant plants often have deeper root systems. These deeper roots make it possible for the plant to search further down for the water they need.
Filling The Bottom Of Your Garden Beds
Before you fill your bed, lay down a 1/4 inch to 1/2 inch of gravel underneath. This allows for excellent drainage and protects the bottom of the bed. Another great benefit of using gravel under the bed is you won’t struggle with weeds throughout the season.
Since you’re putting your highest-quality soil on the surface, whatever’s underneath will need to drain off an excess of moisture. Avoid using materials like rocks on the bottom of your raised bed, as this can create an artificial water table that will prevent good drainage. With raised garden beds, drainage is essential.
What constitutes organic materials? A lot of things!
Old, dry wood can make a suitable base layer, as it will decompose underneath the soil. Wood also holds some moisture while allowing excess to easily drain away.
It’ll take a couple years for old branches or small logs to decompose, so keep that in mind. You’ll want to avoid planting your deepest vegetables in wood-filled beds for a while, opting instead for shallow-rooted plants. Using wood in this way is a variation on a technique called hugelkultur.
Other garden waste products can make for a good base layer as well. Grass clippings, dry leaves or leaf mold, trimmings from other plants, and the like can fill in the bottom of your bed. These will break down quickly into the soil, building up the soil’s organic content. However, as they decompose they’ll lose height, and you’ll see obvious signs of your soil level dropping by late in the season. This is still an excellent way to start a brand-new raised bed, as you can continue soil building later.
Do you have a compost pile that’s still not done breaking down? Toss that half-finished compost into the bottom of a bed. It will continue to break down in there. You can mix some local garden soil with it if you’d like, but it’s not required. These lower layers are also great places to bury your bokashi, topping it off with grass clippings and other garden waste before adding soil.
How to FILL Raised Garden Beds CHEAP and EASY
FAQ
How to fill an elevated raised garden bed?
- Step #1: Prepare your garden bed. …
- Step #2: Add a drainage layer. …
- Step #3: Add a layer of ordinary garden soil. …
- Step #4: Add some premium potting mix. …
- Step #5: Water the soil to help it settle & add some mulch. …
- Step #6: Start planting!
What do you put on the bottom of a tall raised bed?
Cardboard and carpenter paper will both break down over time, which is fine for underneath your raised beds, but I recommend using weed barrier cloth under …Jan 10, 2023
How to cheaply fill a raised garden bed?
- Preparing and filling raised beds (on a budget) Below are some excellent free or cheap materials you can use to fill your raised beds. …
- Logs. …
- Large branches. …
- Smaller branches/twigs. …
- Large pieces of Cardboard. …
- Depleted soil. …
- Newspaper. …
- Smaller pieces of cardboard.
What is the best thing to fill raised beds with?
Vermiculite or Perlite: Include these for improved drainage and root aeration. Organic Matter: Mix in well-rotted manure or organic matter for nutrients.Aug 16, 2023
How do you fill a raised garden bed?
There are many methods you can use to fill a raised garden bed: You can layer the soil and compost, popularly known as lasagna gardening, or you can thoroughly mix the soil and compost. Either method is effective, but lasagna gardening is easier and cheaper for a tall raised garden.
Can garden soil fill a raised bed?
Garden soil may seem an obvious choice for filling raised beds, but garden soil usually doesn’t work well. Soil from your garden can be dense, and it becomes even more compact in a raised bed. Over time, this dense soil can impair water flow and stunt root growth.
How much soil do you need for a raised garden bed?
Create a shelf within the raised bed to accommodate 6 to 12-inches of soil. What Is The Best Wood For Raised Garden Beds? What is the best way to fill a tall raised bed or large planter without spending a lot of money? The secret is to put your best soil where you need it and fill the rest of the container with other harmless materials.
Can you build a raised garden bed from wood?
While available in prefabricated kits in many sizes and materials, building raised garden beds from wood is common. After building a raised bed, it’s important to decide how to fill a raised garden bed. Several economical methods of filling raised garden beds will produce healthy crops. How Much Soil Do You Need?
What can you put in a raised garden bed?
The only downside of having such beds is that you have to fill them up occasionally. Things you can use to fill a tall, raised garden bed are: leaves, grass clippings, fruit and vegetable scraps, tea leaves and tea bags, coffee grounds, compost, manure, seaweed, newspapers, cardboard, spent blooms, pine needles, and peat moss.
Can you add Gravel to a raised bed?
Rocks or gravel are sometimes added to raised beds to boost drainage, but this practice can create a false water table and impair water flow. Better options are to grade the soil around the raised bed away from your garden and ensure it has good drainage. Treated lumber is not a good option for filling garden beds.