How To Fill A Raised Garden Bed

Since raised garden beds are quickly becoming the favored method for many gardeners, the question of how to fill a raised garden bed becomes essential. It is critical to select the proper garden soil and amendments.

The organic materials you select determine how the entire season will unfold. You may well have a sprawling compost that will assist you in filling your raised bed.

Perhaps you'd like to fill your raised garden beds with some garden soil mix, or you'd like to build your own using a regenerative approach that relies on an organic matter supply.

Filling raised beds does not have to be difficult or costly, based on what you have on hand. We'll go over how much soil you'll need as well as how to fill raised beds in this blog post.

Deciding what to grow on your raised garden bed

To determine the materials that will fill your raised garden beds, first decide what you want to grow. Most raised beds will thrive in garden soil designed specifically for them. You can, however, add amendments that are specific to the plants you're growing.

Compost, for example, is a great source of vital nutrients for many plants. Mycelia and beneficial microbes that exist in your region's soil profile will be provided by native soil.

Mulching with leaves, wood chips, or grass clippings to keep moisture in and protect roots from extreme temperatures may also be considered.

Perhaps you'd like to try a raised bed gardening technique that involves layering organic materials before covering your raised garden beds with soil and compost where plants can grow. Consider these factors before purchasing fill materials.

Determining the required amount of soil for a raised garden bed

It is important to know the amount of soil and organic material that will be required to fill raised beds. Whether buying in bulk by the yard or buying bags of material, a little calculation is required to get a good estimate of how much soil is needed and what that might cost.

To begin, determine the soil volume of the raised garden bed. This indicates how much material the raised bed can accommodate.

Volume (in cubic feet) = Length (in feet) x Width (in feet) x Height (in feet)

Measure the bed's longest side with a tape measure (length). Afterward, determine the shorter side (width).

Finally, measure the bed's height or depth. If you take these measurement data in feet, the total volume will be in cubic feet.

Using the same quantity of soil as calculated would leave you significantly short. Garden beds are meant to be full, and the little amounts of space quickly add up, particularly once the soil has been watered in and settled!

Hence, it is strongly advised to obtain sufficient garden soil to top off your raised beds later. As the initial soil settles in and fills every inch of space, it’ll still sink several inches into the bed.

Deep beds may still have enough space for roots, but shallow beds will almost certainly require topping off to maintain a productive garden. A few more inches of soil could very well make all the difference in the world!

Best ways to fill a raised garden bed cheaply

Let's discuss the different ways of filling raised garden beds without spending a fortune. Of course, there are still more ways to fill raised garden beds, but this section will focus on the most cost-effective options.

Most of these gardening techniques are based on providing your plants with nutrient-rich, constantly replenishing raised bed soil.

That means you won't have to do as much upkeep to keep your filled raised garden beds looking good year after year.

Use one or more of the listed approaches to create a lovely and thriving garden bed without breaking the bank, especially when planting annual plants.

1. Hugelkultur method

The hugelkultur method is among the most effective means to build healthy soil while also saving money. The procedure is straightforward.

It entails laying a foundation of large rotting logs and thereafter covering them with smaller branches and twigs. You should also include logs that will decompose over time; large pieces are required.

Fill in gaps between branches and logs with kitchen scraps, grass clippings, compost, wood chips, shredded leaves, and occasionally leftover potting soil as you layer.

Then you add a significant amount of extra soil for planting. Amazing soil is being formed underneath the soil surface as rotting debris underneath the surface decomposes.

This rich soil is ideal for retaining moisture and nutrients in your raised bed garden.

When filling a raised garden bed with a hugelkultur, there are a few things to keep in mind.

To begin, this method will necessitate having more soil on hand as your soil level will drop significantly during the decay process.

It is critical to keep adding soil throughout the process. Another thing to keep in mind is that you should consider leaving at least 10-12 inches of space above your rotting composite.

If root crops seem to be your desired output, this enables you to have planting holes that are deep enough for root vegetables.

To do this, dig a trench around the perimeter of the raised bed before laying your large base logs to allow for the plantings above. Layer the logs in the trench to ensure the few inches space before planting.

2. Lasagna gardening

Mulch queen or the sheet mulching method are other terms for lasagna gardening. This popular gardening technique is the simplest on the offset because it does not require digging or tilling in the soil.

The lasagna gardening approach works by stacking organic materials on soil layers in raised garden beds.

This method essentially consists of several layers of organic materials within your garden bed. Below are the steps to take to implement this gardening method:

1. Make the first layer with cardboard

To smother and prevent weeds and grass, place cardboard at the bottom of a raised bed. This will serve as the initial layer and will decompose over time. Adhesives, tapes, and most metals should be avoided in this layer.

2. Use organic materials to create the second layer

Build layers of soil and compost. Straw, leaf mulch, and grass clippings can also be used. It is best to place organic material that absorbs water in this layer. Since everything breaks down gradually, you're essentially making a quality compost bin within your garden bed.

3. Make a third layer out of green waste

Then add a few layers of brown and green matter. The green matter is living tissue derived from animal manure, compost, and kitchen scraps that have been composted. Dried grass clippings, twigs, small branches, and dead materials such as dried shredded leaves are sources of brown matter.

4. Layer of organic mulch 

Add a layer of mulch twice as large as the base. Water these layers and add compost just around half the size of the twig base layer. Then you'll be able to grow crops directly into the bed in a few days.

If you want to improve your sheet mulching technique, dig a little deeper to provide yourself more room to work with. How much space you have can be determined by the amount of material you intend to use.

3. Core gardening method

Core gardening entails creating a sponge in the raised bed's center. It is designed to retain water and spread moisture for two feet in both directions in your raised bed.

The core gardening method help save money by reducing the time you need to water the garden. Here are the simple steps to implementing this method.

1. To prevent weeds or grass from sprouting, place a piece of cardboard on the bottom of the raised garden bed.
2. Create a 10-inch-deep trench through the soil's center.
3. Organic materials like twigs, dried leaves, straw bales, or grass clippings can be used to fill the core. You can choose one of these composites or a combination of them.
4. After, fill the rest of it with high-quality soil. You can use inexpensive topsoil or potting soil, manure, vegetable waste, or organic compost.
5. Above that, you'll layer your soil blend, which could be bagged soil or a soil mix you made from worm castings and other ingredients.

This trench can look just like a mound in the center of your garden and must be thoroughly watered so that it can provide moisture to your plants all through the gardening season.

You are constructing a compost bin within your raised bed. Microbes feed on the organic materials as it degrades, forming productive working relationships between soil and plants.

4. Ruth stout gardening

Ruth Stout is the conventional gardening method, and it's also simple enough for even inexperienced gardeners to follow. To ensure that the raised garden beds are properly filled, follow these steps:

1. Collect twigs, a pile of wood chips, leaves, and much other organic matters.
2. Plant them in the soil after digging six inches into the wood chip layer. Make sure you know what kind of wood chip to use.
3. The idea behind this method of gardening is to cover all exposed soil with organic mulch, which will eventually decompose and provide nutrients to the plants while also helping the nutrient rich soil to retain moisture. Using this method expedites the filling of your raised bed!

4. Homemade compost

Making your compost helps you to save money as it’s free whereas, bagged compost is pricey; it's like a treasure for your garden. However, making your own compost at home demands only time and household scraps.

If you will like to use compost to fill your raised garden bed cheap, you should start your compost pile the year before you build the beds.

Compost tends to take six to twelve months to generate, so plan ahead of time. Shredded leaves, grass clippings, newspaper, kitchen scraps, and other ingredients will be added.

5. Peat moss

Since peat moss is acidic, you should avoid adding too much to your soil unless you're growing acid-loving plants such as sweet potatoes, peppers, or azaleas.

Adding peat moss to your soil, on the other hand, is an excellent way to bulk it up without purchasing additional bags of topsoil or potting soil.

6. Composted manure

Do you have any farm animals? Compost their waste and use it to fertilize your garden.

You should never add fresh animal manure to your garden. Manure contains a lot of nitrogen, and once you plant in it too soon, it will burn your plants and kill them.

The ideal manure to use is a cow, rabbit, horse, goat, sheep, or chicken manure.

Due to the bacteria in the waste, don't use manure from humans, dogs, or cats. You should compost the manure for about a year, so plan ahead of time.

However, because animals produce an infinite amount of waste, it's the ideal way of filling raised beds cheaply.

7. Add aeration materials

Whatever method you use to fill raised beds on the cheap, you must still add materials that will help create good drainage and promote aeration.

Aeration promotes proper airflow all through the garden bed soil, causing water to reach the roots and preventing compaction.

You also don't want to add many aeration materials to your new raised bed as they will cause the soil to lose its ability to hold water. Coarse sand, perlite, lava rock, or pumice are all good options.

Frequently Asked Questions

Is it possible to fill a raised bed with only compost

No. Simply adding compost to your raised garden bed will end up making your plants less healthy.

Pure compost depletes the level of oxygen in the soil, causing the plants roots to rot. It also can affect the color of the plant's leaves.

Compost is beneficial to plants in providing nutrients and adding quality to the soil when properly mixed with potting soil and topsoil. It is only recommended that you use 30% of it.

Is topsoil suitable for raised beds? 

Topsoil is an important component of the soil mixture used mostly in raised beds, but it cannot be used solely to fill one's garden bed.

Topsoil is simply a filler as it increases the amount of soil in your garden bed.

Plants, on the other hand, require an abundance of nutrients, whereas topsoil lacks the organic matter required for your plants to thrive. It typically should account for 10-20 percent of the soil mixture.

Is it necessary to remove weeds from the bottom of the raised beds?

No, you don't have to remove weeds at the bottom of the raised beds, though not eliminating weeds makes it easier for the weeds to grow and invade your bed.

One of the best practices is to simply cover the bottom of your raised bed with cardboard to keep the weeds at bay.

Final thought - How To Fill A Raised Garden Bed

All you have to do now that you know the ways of filling raised beds is to make a decision on which method you’ll use.

This may seem evident, but each method accomplishes the same goal: building soil with organic matter and always covering it with mulch.

This is how nature operates! All you have to do is quicken the process for your organic gardening needs.