Growing Media
Growing media samples, top row from left to right: loose coir ready for planting; 10mm diameter sharp gravel; hydroton.
Bottom row from left to right: 50/50 mix of perlite and vermiculite; red lava rock, rockwool growing cubes.
Growing media forms a crucial part of any
hydroponic system. A grower's choice here can have functional,
financial and logistical implications. Unfortunately, the array of
available materials and products is mind-boggling, and it seems more are being
developed every day. Each product has its own combination of affordability,
weight, water retention, pH impact, dust, and availability. No one type is
"the best" for all circumstances. Different system setups, different
crops, different growing plans and marketing plans will each dictate slightly
different optimum combinations. And of course our wallets often have a fairly
significant contribution to make in which type we select. So how is a
grower to choose? We offer this summary table to help you make that
choice.
Growing Media Summary Table
The below comparison provides a quick rundown of the different materials commonly used in hydroponic systems, and their various pro's and con's. Each growing medium in the table also has a dedicated web page describing that material in much greater detail. For those media which we have used here, we have provided a summary of our own experiences while using that product. Those individual pages are available via the hyperlinks in the table.
| Cost | Weight | pH Impact | Water Retention | Dust/Debris | Availability | |
|---|---|---|---|---|---|---|
| Gravel | Low | High | Possibly | Lowest | Needs Initial Rinse Only | Common |
| Sand | Low | Highest | Possibly | Low | Possibly | Common |
| Lava Rock | High | Medium | No | Medium | Needs Initial Rinse Only | Uncommon |
| Coir | Medium | Lowest | Yes | Medium | Yes | Common |
| Rockwool | Medium | Low | No | High | No | Uncommon |
| Hydroton | High | Medium | No | High | Needs Initial Rinse Only | Uncommon |
| Perlite / Vermiculite | Low | Low | No | Medium | Perlite Needs Initial Rinse | Common |
The above table provides a huge amount of
information. It took us awhile to compile it, and it will take awhile for
anyone new to this topic to digest all the possibilities. If you are trying to
decide which type to use, we invite you to read through these individual pages,
and take your time. I hope somewhere in this you found some answers to your own
growing needs.
We are continually looking for more product
options. If you hear of another material that we haven’t covered in the above
summary table, let us know and we’ll add it to the list above, with a complete
review. If you have more questions about one of the options already listed, let
us know and we’ll look at answering those questions. This website exists to
help you with your growing goals. Let us know if there’s any other way we can
help you achieve those goals.
Additional Resources
We're not the only ones who are comparing and evaluating various products. Academic institutions, hydroponic and aquaponic companies, and individuals are researching all these products and posting what they've learned. For instance, the University of Arizona released this comparison between rockwool, perlite, coir and blends, for use in tomato cultivation. This senior research project from Lynchburg University compared soil, gravel and coir in two different aquaponic systems. While aquaponics has some differences from hydroponics, there are enough similarities in growing media requirements that this comparison will give valuable insight. Google "hydroponic growing media comparison" for many more such reports and articles.