Raised Bed Soil Mix Recipe - Learn To Grow Gardens (2024)

Raised Bed Soil Mix Recipe - Learn To Grow Gardens (1)

Raised Bed Soil Mix Recipe

It’s no secret that raised beds are great for growing plants. They drain faster, have fewer weeds than in-ground beds, and have a whole list of other benefits, which I go into in more detail in this post.

One of my favorite advantages to growing in raised beds is the use of healthy soil from the very beginning. When planting directly in the ground, the native soil can leave a lot to be desired. It’s often full of weed seeds, lacking in nutrients, and can have issues with drainage. When we plant in raised beds, the soil is nutrient rich, weed free, and drains well.

This, however, depends on the type of soil we start with. While there are many options for filling raised bed gardens, you want to make sure you’re choosing a nutrient rich, well draining blend that’s good for growing plants.

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What makes good soil?

Good soil is made up of several characteristics that create an ideal environment for plants to grow. These characteristics include:

  1. Good texture. The right texture in soil means that it’s able to allow water to run freely through it, plant roots to spread out and grow, get also hold plants upright, the right mixture of sand, clay, and loam create soil with a good texture.
  2. Ability to hold moisture, yet drain well. When watering plants, you want the water to run through the soil and drain well to prevent the roots from sitting in soggy soil. Some of that water needs to stick around, though, to keep plants from drying out. Good soil has the right balance of holding moisture yet having good drainage.
  3. Full of nutrients, especially Nitrogen, Phosphorus and Potassium. Plants need nutrients to grow. Along with macro nutrients, they also need several micro nutrients, such as calcium, magnesium , and sulphur. Good soil has a sufficient level of important macro and micro nutrients.
  4. Low weed pressure. Another important feature of good soil is low pressure from weeds. Weeds compete for nutrients, and can choke out the plants you do want. Good soil is mostly free of weeds and weed seeds.
  5. Lots of beneficial microorganisms. Beneficial microorganisms are microscopic organisms that live in the soil. These microorganisms break down organic matter in the soil. They also release nutrients into the soil to be taken up by plant roots, and help control pest and disease populations.
  6. Full of organic matter. Organic matter, such as compost, adds nutrients to the soil as it breaks down. Over time, organic matter helps improve soil texture and feed beneficial microorganisms.
  7. No harmful chemicals or toxins. Chemicals and toxins can enter the soil in many ways. Once they’re in the soil, they can cause a lot of damage by destroying populations of beneficial microorganisms and burning up plant roots. Good soil does not contain harmful chemicals or toxins.

When you’re filling your garden beds with soil, you want to use a high-quality blend that meets all of these requirements. Most raised bed bagged soil mixes are not made from quality materials, or they rely on peat moss, which is not a sustainable product.

In this post, I’m going to share with you a raised bed soil recipe for soil that drains well, is full of nutrients and organic matter, free from weeds and toxins, and uses an alternative to peat moss.

Raised Bed Soil Mix Recipe - Learn To Grow Gardens (2)

Raised Bed Soil Mix Recipe

Raised bed soil is a balanced mix between your own soil in the ground, and potting soil. To achieve this balance , we start with 3 basic ingredients. I’ve provided a list of amendments below that can be added in addition to the 3 basic ingredients, depending on what you’re looking for.

A note about why I don’t recommend peat moss

A lot of raised bed soil mixes call for the addition of peat moss or coconut coir. Although peat moss is a great addition to soil, and is used in many bagged soils and homemade garden soil mix recipes, it is not a renewable product. Additionally, the harvesting of peat moss from peat bogs is contributing to greenhouse gases. You can read more here.

Although coconut coir is a great alternative, and I recommend for my DIY seed starting mix, it can be expensive in large amounts, such as the amount needed for raised beds. For this reason, I suggest using sand in your mix, as I explain below.

How to make raised raised bed soil mix

Our 3 basic ingredients:

  • One part compost
  • One part topsoil
  • One part course sand


Compost is going to give us organic matter, nutrients, and a good dose of beneficial microorganisms, right from the start. It will also help the soil hold misrule, yet drain well. You can purchase bagged organic compost at garden centers, or use your own compost.


Topsoil is sort of our “filler” ingredient. It’s our base in this mix. Top soil is cheap, and a good starting point, but on its own it lacks nutrients and can be more dense than desired for growing plants.

Course sand

Course sand helps break up the density of the topsoil and compost. It helps roots spread and grow easier, and the addition of sand with the topsoil and compost helps create a mix that is similar to healthy garden soil. Makes sure you buy course sand, and not play sand. It should be near the concrete supplies.

Raised Bed Soil Mix Recipe - Learn To Grow Gardens (3)

Raised Bed Soil Calculator

Before purchasing your supplies, make sure to calculate the amount of soil you need. There are a handful of calculators on the internet that will do the math for you, such as this one. To do the math on your own, multiply the width by the length by the depth. This will give you the total cubic feet of soil needed. For example, a popular size for a raised bed is 4 feet by 8 feet by 1 foot. Using those measurements, I would multiply 4 x 8 x 1, which would give me a volume of 32 cubic feet. Bags of soil, compost and sand are sold by cubic feet. For a 32 cubic foot raised bed, I would want roughly 10 cubic feet each of topsoil, compost and sand.

How many cubic feet is a 40lb bag of topsoil?

Topsoil is sometimes sold by the pound. My local Lowe’s sells topsoil in 40lb bags. One 40lb bag of topsoil is roughly .75 cubic feet, so I would want 14 bags of topsoil in our example above..

How to make raised bed soil:

1. Calculate how much soil you need, according to the formula above. Pay attention to the size of your bags of topsoil, compost and sand when making calculations

2. Mix together the topsoil, compost, and course sand in a large container or wheelbarrow. Alternatively, you can mix them inside your raised bed. Just be sure to mix in layers, and not all at one time. For example, if you’re mixing in 8 bags each of topsoil, compost and sand, add 2-3 bags of each to your bed at a time and mix well before adding more.

3. If desired, add 1-2 cups of an organic fertilizer per cubic foot if soil to give your plants an additional boost of nutrients. I like to use Espoma Organic Biotone Starter Fertilizer in my raised beds.

4. Once your soil is well mixed, add it to your beds. Level it out, and be sure to water thoroughly before planting.

Amending raised bed soil

The raised bed soil mix recipe above is a great starter mix for the average flower and vegetable garden. However, on occasion we may want to amend the soil a bit to suit the needs of our plants. Some plants may need a more acidic soil, such as blueberries, or they may need a drier soil, like rosemary or lavender.

The following are some of the best soil amendments for raised beds:

To create a more nutrient dense soil, add the following:

  • 2-inch layer of compost at the end of each growing season
  • Worm castings sprinkled around the surface of the bed and lightly scratched in
  • Rock dust minerals (read more here at GrowOrganic)

To raise the acidity of your soil (after performing a pH test and confirming the need to raise acidity) add the following:

  • Sulfur, such as this product. Apply according to the product label

To lower the acidity of your soil (after performing a pH test and confirming the need to raise acidity) add the following:

  • Lime, such as this product. Apply according to the product label

To adjust moisture or drainage in a raised bed

  • Perlite: lightweight, holds small amounts of water)
  • Worm castings: can hold up to 10x’s their weight in water and helps moisture retention while adding nutrients
  • Coconut coir: absorbs water for later use, and loosens soil. Decomposes over time
  • Vermiculite: absorbs water and releases it into the soil over time
Raised Bed Soil Mix Recipe - Learn To Grow Gardens (4)

Final Thoughts

Although it can be tempting to grab a few bags of bagged raised bed soil to fill up a new raised garden bed, it’s best to create your own mix. If you’re taking the time, effort and money to install a raised bed garden, you should start with the best soil. A custom mix is the best way to ensure you’re creating the right soil mix for your plants needs.

When first filling raised beds with a custom soil mix, it’s best to start with the basic mix and get a feel for how your plants perform in the soil. After the initial period, feel free to experiment and make it your own!

You may also like:

  • 21 Benefits of Raised Beds
  • Gardening Tips For Beginners
  • How To Make Plants Grow Bigger and Faster

Frequently Asked Questions

Can I fill a raised bed with just compost?

Although compost is a great soil amendment, it does not create the ideal soil mixture for growing plants. Compost alone can burn young plants and seedlings, and may have issues with drying out too quickly. Compost should be used mixed with topsoil.

Can I fill a raised bed with just topsoil?

Although topsoil seems like a great standalone option for filling a raised bed, it’s not the best choice for the health of your plants. Topsoil can be lacking in many nutrients, organic matter, and beneficial microorganisms. It’s best to mix topsoil with compost when filling a raised bed.

How to fill a raised garden bed cheap?

When filling a raised bed that is 1 foot or deeper, you can add grass clippings, leaves, or old logs to help fill the bed before adding soil. These additions will break down over time. Be sure to add at least 6-8 inches of a raised bed soil mix at the top for your plants to grow.

Raised Bed Soil Mix Recipe - Learn To Grow Gardens (5)

Hi, I’m Liz! I’m a Master Gardener, Garden Coach, and Professional gardener. I’m also a mom of 4 who likes to putz around in my garden, growing food and flowers. You can read more about me here.

I started Learn To Grow Gardens as a resource for anyone looking to find more success in the garden. You can find gardening help, inspiration, and community through my Facebook Group, Instagram page, and by joining my email list below.

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Raised Bed Soil Mix Recipe - Learn To Grow Gardens (2024)


Raised Bed Soil Mix Recipe - Learn To Grow Gardens? ›

The Best Raised Bed Soil Blend

Add roughly a 50/50 blend of compost (bulk and/or homemade) and topsoil (bulk and/or bagged).

What is the best recipe for raised bed soil mix? ›

The Best Raised Bed Soil Blend

Add roughly a 50/50 blend of compost (bulk and/or homemade) and topsoil (bulk and/or bagged).

What is the soil mixture for raised beds? ›

A general potting mixture of three parts organic matter (such as garden compost, leafmould or well-rotted manure), two parts sharp sand and seven parts topsoil is sufficient for most raised beds. For alpines, bulbs and herbs, that like good drainage, double the proportion of sand.

What is the best soil mix for raised bed tomatoes? ›

The soil is the key ingredient to a successful raised vegetable bed. Get enough light topsoil or raised bed soil to fill the estimated depth of the raised bed. Since tomatoes are heavy feeders and prefer a rich, organic soil, mix in two- to three-inch layers of compost or cow manure to the top one-third of the topsoil.

How many bags of soil do I need for a 4x8 raised bed? ›

As a rule of thumb, a 4'x8' raised bed that is 6 inches deep requires approximately 8 bags of soil while a 4'x8' raised bed that is 12 inches deep requires approximately 16 bags of soil.

What is the best soil mix for vegetable gardens? ›

Types of Soil for Vegetable Gardens

Loamy Soil: The gold standard for most gardeners, loamy soil has a balanced mix of sand, silt, and clay. It retains moisture while ensuring good drainage and is rich in nutrients and organic matter.

What is the best soil for a raised bed vegetable garden? ›

The ideal soil type is sandy loam, which is essentially soil that is loose, well-draining, and rich in organic matter. Oftentimes the native soil in your yard is not suitable for growing plants, as it may have poor drainage or subpar composition. It may also contain heavy metals or pesticides.

How do you fill a raised garden bed cheap? ›

Fill the bottom half with broken branches, twigs and general forest waste. Add green material like grass clippings, weeds (without roots or seeds) comfrey cuttings, kitchen vegetable waste. Top up with 6 inches of topsoil and home-made compost mix.

What is the best soil recipe for a garden? ›

You want the kind that's dark, rich, and loaded with microorganisms. Fill your beds with a mix of 50 to 60 percent good-quality topsoil and 40 to 50 percent well-aged compost. Before each new growing season, test your soil for pH and nutrient content. You can buy a kit at most home-improvement stores.

What is the difference between garden soil and raised bed soil? ›

Raised Bed Soil is like a balance between garden soil and potting mix. It has the exceptional drainage necessary for container and raised bed gardening. It assists gardeners in maintaining loose soil and provides adequate airflow for necessary oxygen and nutrient delivery to root systems.

What should I add to my soil before planting tomatoes? ›

Add compost for the best soil for tomatoes.
  1. Nutrient-packed compost is the best way to improve any type of garden soil—from heavy clay to fast-draining sand. ...
  2. Tomato diseases, such as early blight, live in the soil and plague plants year after year.
Jul 20, 2023

How do I make the perfect soil for tomatoes? ›

Compost and composted manure are great additions to the soil for tomatoes and lots of other plants. Compost adds basic nutrients and improves soil structure. Composted manure provides nutrients all season long.

What is the best fertilizer for raised bed tomatoes? ›

The best fertilizer for tomatoes comes down to preferences. Fish emulsion is a mild, nitrogen rich organic that can be used all season long. If only one type of formulated fertilizer is used, it's best to choose a balanced product such as NPK 10-10-10.

How many bags of soil do I need to fill a 3x6 raised bed? ›

To fill a 3x6 bed with 10" sides, you will need 15 cubic feet of blended soil. To create the blend, use the following quantities: 9 cubic feet of topsoil (9 20-quart bags) 4.5 cubic feet of compost (4.5 20-quart bags)

How often do you change soil in raised beds? ›

Ideally, we think it's best to consider replenishing the soil between each season i.e. after every Autumn/Winter and Spring/Summer harvest; however, if you can only do it once a year, that's alright too.

How deep should raised garden 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.

How do you make the perfect soil mix? ›

A mixture of 70% garden soil and 30% organic matter creates a good general potting mix for planting up trees, shrubs, perennials and fruit. If your garden soil is heavy, reduce the soil content by around 10% and add some sharp sand, grit, or bulky organic matter in its place to improve drainage.

How to fill raised beds cheaply? ›

Here are some cost-effective ways to fill your raised garden bed:
  1. Use Your Existing Soil: If you have good-quality garden soil on your property, consider using that as the base layer in your raised bed. ...
  2. Composting: Compost is an excellent, nutrient-rich option for filling raised beds.
Jan 1, 2023

How do you make a good garden soil mix? ›

Place equal parts of top soil, peat moss, perlite, and compost in the bucket. Add in a half a cup of garden lime, and a good handful of bone meal. Use a hand shovel to thoroughly mix all the ingredients until they are incorporated.

What is the best fertilizer for raised garden beds? ›

What's the best fertilizer for a vegetable garden? 9 top feeds to boost your harvests
  • Manure.
  • Blood meal.
  • Bone meal.
  • Comfrey feed.
  • Tomato feed.
  • Sulphate of potash.
  • Sulphate of ammonia.
  • All-purpose food.
May 4, 2023


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