Soilless Grow Media for Ultra-Efficiency Systems

The Advantages of Growing in Pumice

Pumice is one of Mother Nature's unique and widely useful creations. Born of earth and fire, pumice is essentially a whipped foam of volcanic glass—each stone made up of highly vesicular strands permeated with tiny air bubbles.

The physical and elemental properties of pumice give it its unique and infinitely useful qualities—qualities that are welcomed in a wide range of industrial and practical applications. That includes horticulture.

Pumice in Horticulture

Pumice is used widely to improve the growability of soils—combating compaction and runoff, improving friability and aeration, and holding moisture and nutrients in the root zone.

With the rising popularity of high-efficiency growth systems, especially aquaponic systems, pumice provides many advantages as a soilless grow media.

Why Pumice as a Soilless Grow Media

When considering which grow media to use, these key points should be considered:

Nutrient Holding Capacityan effective grow media must have the ability to retain that nutrient-rich water for a time, making it continuously available to the roots between watering cycles. Ponics Stone™ grow media is 100-percent pure, natural pumice. This volcanic foamed stone is riven with countless tiny pores that function as microscopic reservoirs to capture and store nutrient-rich moisture and give it back to the root system as needed. That allows for less frequent watering cycles and avoids problems like algae growth. That also saves energy and reduces the wear and tear on the system.

The porous, foamy nature of pumice also makes for an ideal environment for beneficial microbes to thrive.

DrainageBalance is so important: a grow media must be able to shed water quickly to allow air into the root zone, yet retain enough nutrient-rich moisture between irrigation cycles to fuel rapid growth. The pores that perforate the pumice stones in Ponics Stone™ are (naturally) not the same size or shape—and it is this natural variety in pore size, depth, and shape that provide the needed balance. The tiny, microscopic pore sizes hold water and make it available as demanded by the root system. The large pores drain quickly, shedding water and taking in air.

Gas Exchangea grow media must allow free-flowing exchange of oxygen and carbon dioxide in the root zone. The highly porous, low-bulk nature of Ponics Stone™ facilitates an effective and positive exchange of gases between the root zone and the environment.

Stabilitythe grow media must be substantial enough to support a plant’s root system, as it is the root system that support the plant and the fruit it bears. Ponics Stone™ soilless grow media is lightweight, yet substantial enough not to float away. The grippy surface of the little pumice stones form a stable bedding matrix to support thriving plants.

WeightGrow beds tend to be positioned above ground/floor level to allow a sump tank underneath and/or to provide easy access when planting and harvesting, and that means grow media weight is an issue. Since pumice is essentially a foamed glass stone, it is less dense and weighty than gravel or sand. One cubic foot of Ponics Stone™ weighs in at approx. 45 lbs.

Crop Balance—As a grow media, pumice provides good drainage, excellent moisture retention, and increased gas exchange necessary for both vegetative and reproductive (fruit) growth.

Media Particle Sizes—Ponics Stone-brand stones are not man-made, but rather natural pumice crushed and screened to the ideal size. Available sizes:

• PONICS STONE™ (3/4" - 5/16") All-purpose soilless grow media for ponic media beds and other growing systems. This pumice stone size blend provides good drainage and germination.

• PONICS STONE™ PREMIUM (5/16" C) Premium Ponics Stone™ demonstrates increased germination rates when sown directly in top-dressed media beds and net pots. This is the ideal media for shallow micro green beds.

Long LifeTo be able to continually replant in the same grow media saves time and money. Ponics Stone™ is enduring—lasting years in a properly designed and maintained system.

Nutrient Value Contributed by the Grow Media—Ponics Stone is slowly broken down over the months and years by microbial action, providing an ongoing supply of important nutrients to the system, especially silicon, which is a oft-missing yet important element (delivers strength, resistance to pests and disease, all-around hardiness to plants) in soilless grow systems.

Sustainable and Green

Since the entire suite of pumice's useful properties are bestowed by nature, the process to prepare pumice for market is simple, sustainable, and green.

Our pumice grow media is not manufactured—it is simply removed from the deposit, crushed, dried, and screened to size.

• No super-heating was necessary, which means lower carbon production emissions than the “expanded” and recycled growing medias on the market.

• No chemicals are used to produce Ponics Stone™.

• No water is needed in the production of Ponics Stone. Even the pumice dust that clings to the particles is useful—providing readily soluble trace minerals and nutrients to the system.

• Hess uses a low-impact, surface mining process to acquire the pumice. The soil (overburden) is set aside and used to reclaim and replant the mined area, returning the land to its natural state of high-desert grassland.