Soil vs Dirt: Best Growing Media Guide for Gardeners

I want to answer a couple of common questions I’ve received from some of you — what’s the difference between dirt vs soil, and how do you choose or make the right media for your plants?

Dirt vs Soil Explained

Many people use the words “dirt” and “soil” interchangeably, but there’s a big difference:

· Dirt is made up of sand, clay, and silt, but it lacks nutrients.

· Soil is dirt with nutrients, usually some form of organic matter, making it capable of supporting healthy plant growth.

Real Example: Sandy Yard Conditions

For example, my own yard in Steinhatchee, Florida, is mostly sand and silt—what I’d call “dirt.”

Sandy, Florida soil

The dirt was mostly formed by the sand and silt pushed up from the gulf and river which forms high dunes made by large waves and wind. The road I live on is 19’ above sea level, which has saved us from the flooding caused by the last few hurricanes that devastated homes blocks from me. With that said, the rain over the years has washed through the dirt, predominantly sand, and any nutrients being washed down deep beyond the roots with it.

Nutrient Loss and Native Growth

Years of this has also removed the salt, which allows native vegetation to grow, such as palms, cedar, and other vegetation that tolerate these conditions, but non-native plants need a boost.

Soil Testing and Improvement

When I did a soil test in the yard, it indicated that I had almost no nutrients, so I needed to add them back in to produce soil that would grow non-native vegetation.

Testing soil with a soil testing kit

Planting Strategy for Fruit Trees

When I plant fruit trees like citrus, pomegranate or figs, I dig extra-large holes, larger than the root ball, and add organic matter to hold nutrients and moisture, which helps the plants get established. Adding nutrients only this one time isn’t going to last forever, you do need to fertilize periodically.

Tip: Always remove the top layer (4-6 inches) of organic matter when taking a soil sample for testing. This gives you a true picture of the nutrients at the root zone.

Choosing and Making Potting Media

I’m often asked what kind of media I use for seeding and potting, or if I make my own. I no longer have acres of land or a nursery, but when I did, I was making my own media.

Hydroponics and Soilless Growing

My knowledge of growing with various media actually started when I was working for the University of Florida managing hydroponic greenhouse research and demonstrations. Most people believe that hydroponic means growing plants in nutrient film technic (NFT) alone. This is when plant roots are periodically irrigated and fertilized without soil.

However, growing hydroponically means you are growing with soilless media, such as perlite, peat, composted pine bark mulch, coconut core, and others. These various media do not have nutrients, so every time the plants are watered they receive nutrients that are mixed in the water. There is a lot more to it, of course!

Homemade Potting Mix

For homemade potting media, I use a blend of peat, coconut core or pine bark mulch, and perlite for aeration. For moisture-loving plants, such as African violets or in very dry conditions, I add vermiculite. Remember, these mixes need added nutrients—good homemade compost works well.

Compost and Organic Additions

I worked with an organic herb nursery in Madison, FL, where she had access to mushroom compost. She not only used this in her media, but also sold it in bags, which I purchased for my needs.

I also had access to composted chicken manure. I had worked with a grower that tried using chicken manure that was not properly composted. It was dried from the raw state and quickly his crop showed major failure. The tests showed that the manure had high levels of boron which appeared to be burning the roots. So proper composting is paramount for many reasons.

Regional Availability of Materials

Where you live can determine what is easily accessible and more affordable. For North Florida, pine bark mulch was our choice because pines are a crop around here, so the various sizes of bark is a byproduct. I would buy the bags of peat in garden shops, since that is taken from peat bogs in the north.

Homemade Soil Formula

So, when I made homemade soil, I typically used peat, perlite, mushroom compost or composted chicken manure (from my research experience, you only need a very small amount of chicken compost, so what I had lasted a long time). When available and I needed them, I used other amendments, as well.

Seed Starting Tips

For seeding, avoid large particles in your media. Sieve out big chunks so seeds aren’t buried too deeply. If they are covered, it makes it difficult for them to come up to the surface. Larger seeds can usually overcome this, though. Once seedlings are larger, chunkier media helps with drainage and root growth.

Practical Gardening Tips

A few practical tips for home gardeners:

· Test your media’s drainage by putting some of your media in a pot and water it to make sure it drains properly before using it for planting.

· Use a soil test kit to check pH and nutrients.

· Consider watching my YouTube video on soil testing for extra guidance!

Store-Bought Media and Fertilizers

Now that I am no longer growing hundreds of plants, I am buying various media for the things I grow. Many of these indicate that there is fertilizer in the mix, putting them in the soil category. This added fertilizer will help with the initial growing process, but as you water and it rains you will need to continue to add fertilizer (I love using fish emulsion).

Recommended Product

I have found media I like to use for sowing seeds in local garden shops, but because my closest store is 35 to 50+ miles from where I live, I get it from Amazon. This is a good option —Miracle-Gro Seed Starting Potting Mix

Remember, gardening is a journey—don’t be afraid to experiment and learn as you grow!