What's In Our Potting Soil?

What is in the soil mix used at Costa Farms?

What’s in our potting soil and why do we use it?

It’s primarily coco coir, a waste product of the coconut industry. Our growers have thoroughly tested a wide variety of options that, most importantly, encourage strong root growth, but also fit within our sustainability standards. Coir, basically shredded coconut fibers, works well for potted plants because the fibers absorb moisture like a sponge. This makes moisture available for plant roots. Because the small coir fibers can compact and become too dense, we also use shredded wood fibers (a byproduct of the lumber industry here in the Southeast) to increase aeration, ensuring plant roots can breathe. Coir is also a sterile medium, so it doesn’t carry disease.

When compared to peat moss which is harvested from bogs where it has developed over millions of years coco coir is a wholly sustainable and renewable resource. When peat is harvested a large amount of carbon is released into the atmosphere. Peat moss takes 25 years to renew after a harvest whereas the coco palm fruits regularly and without scaring the Earth. The coconuts and wood fiber we use is local and sustainably sourced.

Read more about how coconut coir beats peat moss in sustainability.

Coir is a good choice for most tropical plants unless you tend to be an over-waterer. Coir holds moisture more effectively than peat/traditional soil mixes, so those who water sparingly or check soil moisture levels before watering will find success. Coir doesn’t hold nutrients well so you will need to fertilize.

What Else is in the Soil?

The other main ingredient in our soil is called HydraFiber. If you look at the surface of the potted plant below you will what looks like long string like things that can resemble roots.

HydraFiber is a modern, sustainable growing media made from refined wood fibers, and it's increasingly used in both professional horticulture and retail potting mixes. It’s designed to replace or reduce traditional components like peat moss, perlite, or coir—while improving root development, water management, and air flow in the soil.
 
What Is HydraFiber Made Of?
It's made from Southern Yellow Pine wood chips that are:
Mechanically processed (not chemically treated)
Refined into ultra-fine fibers
 
These fibers are light, springy, and highly absorbent, which helps retain moisture while still allowing for excellent aeration.
 
Why Is It Used in Potting Mixes?
HydraFiber is a popular peat alternative or supplement, especially in commercial nursery production and increasingly in consumer potting soils.
 
Benefits:
Great water retention while still draining well
Increased air space for better root oxygenation
Reduced compaction over time (holds its structure better)
Sustainable and renewable (comes from managed forestry sources)
Consistent quality—less variability than peat
 
How It Performs in Soil:
HydraFiber holds onto water like peat, but allows for better airflow, similar to perlite or bark. It's often mixed in at 10–40% of a potting mix, depending on the plant’s needs.