Raised Bed Soil Calculator

Welcome to the raised bed soil calculator, your go-to tool for figuring out exactly how much soil you need for your next gardening project. Whether you’re planning a single veggie bed in your backyard or managing a more ambitious setup with a dozen raised beds in a greenhouse, we’ve got you covered.

Choose from our predefined soil mix recipes to find the best soil for your raised beds — or create your own custom blend and quickly calculate the amount of each ingredient required.

Wondering how to calculate soil for a raised bed? Let’s dig in! 🧑‍🌾

The best soil for your garden project depends on your needs and the plants you want to grow.

1. Essentials

No matter what your end goal is, compost and topsoil are essential components in almost all recommended raised-bed soil mixes. But let’s first understand — what they really are?

• Topsoil

  This is basically the upper layer of soil, typically described as the first 5-10 inches (13-25 cm). It has a high concentration of microorganisms, nutrients, and organic matter, and it provides habitat for organisms such as earthworms. Topsoil also plays a crucial role in the distribution and retention of water and air, both of which are essential for biological activity and plant growth.
  
  

• Compost

  An additional nutritional boost for plants, compost improves soil fertility and structure. It consists of decayed organic matter, such as plant material, food waste, and manure. Compost is produced by combining the right proportions of “greens” (nitrogen-rich materials: e.g., food scraps, fresh plants, grass clippings, herbivore manure) with the “browns” (carbon-rich materials: e.g., dead leaves, woodchips, shrub prunings, cardboard). As these materials decompose, they form the “black” — dark, nutrient-rich product known as compost 🟢 + 🟤 → ⚫️
  
  

2. Supporting materials

Additionally, blend recipes can include a variety of other ingredients, such as:

• Organic matter — for enriching soil and supporting microbial life;
• Coarse sand / perlite — aeration agents that help prevent soil compaction;
• Coconut coir / peat moss — supporting moisture retention;
• Vermiculite — improves moisture control, aeration, nutrient retention;
• Worm castings — a nutrient-rich organic fertilizer with long-term effects; and
• Well-rotted manure — adding nutrients and improving soil fertility.
  
  

3. Bottom-fillers

If a raised bed is deep (over 20 in / 50 cm), you can add bottom fillers to reduce cost and avoid filling the entire volume with the soil mix. Organic materials are a practical and economical option here, and they gradually improve the bed as they decompose. Use what you have at hand — these can be logs, branches, wood chips, leaf mold, or straw, to name just a few options.

To calculate the soil for a raised bed, all you need to do is measure your bed and choose the proper mix.

Let’s have a look at the process — step by step — how to use this raised bed soil calculator:

1. Measure your raised bed 📏

2. Input raised bed length and width into calculator.
3. Enter the soil depth — how much soil you want to put into your raised bed.

4. Total soil volume appears! 🌱
5. If you‘re not using ready-made raised bed soil mix, you can go to the next section and:
   • Either choose a predefined soil mix for raised bed gardens; or
   • Enter the blend ratios yourself, if you need a more personalized approach to your garden project.
6. As a result, you‘ll see exactly how much of each soil component you need! 🌱🌱🌱

After these raised bed calculations, you should also check different tools that should be very beneficial for your gardening journey:

• Omni’s plant spacing calculator answers the question of how many seedlings you will need for your raised beds;
• Our vegetable planting calculator and vegetable seed calculator will help you get the most out of your veggie harvest; and
• Soil calculator — if you need a generic tool for any soil calculations, also covering the economic aspects.

It’s simple — you just need to:

1. Choose a soil mix recipe.
2. Calculate the total volume you need (based on your raised bed size) and the ingredients volume.
3. Gather your components — buy them or source locally (e.g., garden topsoil, compost from a nearby farm, etc.)
4. Mix everything thoroughly and water the mix before planting.

Our raised bed soil calculator is coming in handy for supporting the first two points — helping you choose the recipe and calculate the amount of each component (sorry, our tool can’t help you mix the ingredients — yet 😉 ).

Happy gardening! 🌱