Soil vs. Dirt: Understanding the Difference and How to Make Your Own Soil

Hey all! Real Farmer Jeff here.

Whether you’re a beginner gardener or a seasoned grower, understanding the foundation of plant health – soil – is crucial.

Many people use the terms soil and dirt interchangeably, but in gardening and agriculture, they are very different things.

Let’s break it down and then explore how to create your own nutrient-rich soil using trusted methods like Mel’s Mix, potting mix, and other popular soil-building techniques.

From compost to fertilizer to coconut coir, I will walk through my recommended amendments for you to make your garden’s best nutrient-rich soil.

Let’s get started!

What is Potting Mix (AKA Potting Soil)?

Despite the common use of the term “potting soil”, most commercial bags are actually soilless. They contain no real soil or dirt. Instead, they’re blends of organic and inorganic materials designed to meet the unique needs of container-grown plants.

Common Ingredients:

• Peat Moss or Coconut Coir: For moisture retention
• Perlite or Vermiculite: Improves drainage and aeration
• Compost or Bark Fines: Adds nutrients and texture
• Slow-Release Fertilizers or Worm Castings: Optional but beneficial

Is Potting Mix the Same as Potting Soil?

Technically, yes: The terms are used interchangeably in stores.

Practically, no: Because neither usually contains actual soil. “Potting soil” is a misnomer for what’s really a custom-blended mix tailored for potted plants.

When to Use Potting Mix:

• Not the best choice for large raised beds due to cost and water-holding capacity
• Ideal for container gardening or indoor plants

Method 1: Mel’s Mix (From Square Foot Gardening)

Ingredients (by volume):

• 1/3 Peat Moss or Coconut Coir: Moisture retention
• 1/3 Vermiculite: Aeration and drainage
• 1/3 Blended Compost: Nutrient source

Use compost from at least five different sources for a broad nutrient range (e.g., leaf mold, worm castings, mushroom compost, cow manure, green waste).

Ideal For:

• Raised beds, especially in square-foot gardens

Pros	Cons
Balanced, low-maintenance, weed-free	Initial cost (mainly from vermiculite)
Great texture and fertility for vegetables and flowers	Peat moss is unsustainable (coir is the eco-friendlier choice)

Method 2: Best Soil Mix for Raised Bed Gardens

If you want an affordable and effective raised bed mix, try this:

DIY Raised Bed Mix (By Volume):

• 50% high-quality compost (multiple sources)
• 30% coconut coir or peat moss (for moisture control)
• 20% perlite or coarse sand (for drainage)

Add:

• A handful of worm castings per square foot for microbial life and nutrients
• Rock dust or greensand for trace minerals (optional but great long-term)

This mix is perfect for vegetables, herbs, and flowers, and it’s easy to refresh each year by topping with more compost and mulch.

Method 3: Lasagna Gardening (Sheet Composting)

Layer organic materials directly into the bed to create soil in place. Here’s how you want to layer:

1. Cardboard/newspaper
2. Browns (dry leaves, straw)
3. Greens (kitchen scraps, grass)
4. Finished compost
5. Optional layer of soil for immediate planting

Ideal For:

• Soil-building over time
• In-ground beds

Do I Need to Fertilize a Homemade Soil Mix?

Homemade soil mixes, especially those made with compost, often start out nutrient-rich. But depending on what you’re growing, compost might not be enough to sustain plants over time. Especially heavy feeders like tomatoes, squash, and corn.

So, Is Compost Enough?

It depends on:

• Whether you’re growing in containers or in the ground
• The quality and variety of the compost
• The nutrient needs of the plant

If you’ve used:

• Compost only, no fertilizer: great for leafy greens, but you may need to supplement for fruiting crops
• Multiple compost sources (e.g., worm castings, leaf mold, manure): you’re starting off strong
• Store-bought compost only: may be lower in diversity and microbial life

How to Fertilize a Homemade Soil Mix

Here’s how to keep your soil productive through the season, especially in raised beds and container gardens, where nutrients are used up more quickly.

1. Add Slow-Release Fertilizers at Planting Time

Slow-release fertilizers provide a steady supply of nutrients over weeks or months.

Examples:

• Granular organic fertilizer (like Espoma Garden-Tone or Dr. Earth)
• Pelletized chicken manure
• Compost + worm castings blend

Tip: Mix into the top 4 – 6 inches of soil before planting.

3. Use Liquid Fertilizers for Quick Boosts

This is especially helpful for containers or when plants look pale or sluggish.

Organic Options:

• Compost Tea: Made by steeping compost in water for 24 – 48 hours
• Fish Emulsion: High in nitrogen, great for leafy growth
• Seaweed Extract: Rich in micronutrients and helps with plant stress

Apply every 1 – 2 weeks during the growing season.