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 my trusted method, 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 and Potting Soil?

Although “potting mix” and “potting soil” are often used interchangeably, they’re not quite the same. Potting mix is a soilless blend made for containers, while potting soil usually contains real dirt and is better for outdoor beds.

Potting Mix

• Soilless, made of peat or coco coir, perlite, and bark.
• Light, airy, and sterile, promoting good drainage and healthy roots.
• Best for containers and indoor plants.
• Often low in nutrients, so fertilizers or compost must be added.

Potting Soil

• Contains real soil, often mixed with compost or sand.
• Heavier and may hold more moisture but can compact in pots.
• May contain pests or weed seeds if not sterilized.
• Naturally richer in nutrients than soilless mixes, though quality varies.
• Better suited for garden beds or large raised beds.

• 50% high-quality compost
• 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
• Organic fertilizers; see below

Benefits of Inorganic Additives (Perlite, Sand, Pumice):

• Improve Drainage: Prevent soggy roots by opening soil structure.
• Boost Aeration: Let oxygen reach roots for healthier growth.
• Prevent Compaction: Keep soil loose and root-friendly.
• Last Longer: Unlike organic matter, durable minerals maintain structure.
• Stabilize Temperature: Pumice buffers heat and cold.

What’s the difference between perlite, sand and pumice?

Material	Key Benefit	Longevity
Perlite	Lightweight aeration, drainage	~2–5 years; can crush and compact
Sand	Stable drainage, prevents compaction	Essentially permanent
Pumice	Aeration, drainage, slight water retention	Many decades; very durable

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.