Horticultural Applications for Pumice
When it comes to growing vibrant plants and turf, it’s all about the quality of the soil. The root systems of plants require a continual supply of oxygen, and the carbon dioxide respirated by the roots must be able to leave the root zone. This all-important exchange of gases is key to a good growing medium.
That means the soil must resist compaction, yet be able to retain water and hold onto the nutrients necessary for plant growth. Adding pumice to garden soils and growing media can help meet those critical requirements.
Pumice is an excellent soil conditioner, as it is highly porous, giving it excellent water and air holding properties. Advantages of using pumice in potting media and garden soils include:
—the porous nature of pumice allows it to hold vital nutrients in the microscopic surface pores, which helps regulate fertilizer feedings. It can even be supercharged with nutrients before it is added to the growing medium.
—excellent conditioner for soils that need increased aeration and drainage, as when growing cacti, bromeliads, succulents, or when rooting cuttings.
—loosens the density of heavy clay garden soils, letting in the air and water plants need.
—increases water retention in light and sandy soils.
—makes tillage easier.
—reduces crusting, cracking, flooding and shrink-swelling.
—holds moisture in the soil, reducing watering requirements, yet pumice will not compact or become soggy.
—pumice is inorganic, so it will not decompose or compact over time, meaning it functions continuously and can be recycled and reused.
—pumice is pH neutral.
—pumice does not attract or host fungi, nematodes, or insects.
—pumice makes an excellent component to composts, mitigating volatilization during composting and then contributing in-soil.
These advantages can be realized with as little as a 10% addition of pumice to the soil or growing medium.
For the same reasons detailed above, pumice is a high-performance addition to a soil when preparing a quality seed bed for new turf areas. Pumice-enhanced soils can solve issues with native soils being susceptible to compaction or having a poor water and nutrient retaining structure.
Public parks, sports fields and golf courses—which receive a lot foot and cart traffic and have extensive water and fertilizer demands to remain attractively green—benefit greatly from the enhancements imparted by pumice in the soil. In arid regions, the water-retaining porosity of pumice will decrease irrigation demands.
Pumice can also be used with existing turf as a top dressing after aerification on heavily-trafficked lawns or greens to restore or maintain proper soil structure.
Roadside vegetation is critical to keeping the soil locked down and to prevent damage to roadway drainage ditches, embankments, steep-cut slopes and other areas sensitive to severe erosion. The vitality and vigor of that vegetation will greatly benefit from the horticultural enhancements (air exchange, water and nutrient retention) provided when pumice is present in the soil. The growth-supporting quality of the soil is particularly important when effort and expense is put into seeding and mulching these engineered areas, especially in drier climates.
On the same principle, for engineered drainage channels and ecology embankments along roadways and runways, pumice can be liberally mixed with dense, heavy native soils with poor water-handling properties to enhance drainage, absorption and retention, thus reducing water-related problems along maintenance-intensive transportation corridors.
A 1992 study done by the Department of Horticulture at the University of Illinois found the physiochemical properties—and hence, the performance value as a soil amendment—to be similar to those of perlite. Perlite enjoys a well-documented and successful place in potting soil formulations, but perlite is not as cost-effective as pumice for large-scale soil-conditioning projects such golf courses, urban parks and green belts, sports field complexes, high-value crops on limited acreage, ecology embankments, and reclamation projects.
Landscaping Mulches with Pumice Stone. Coarse-grind pumice makes an excellent and attractive mulch for flower and shrubbery beds. The soil beneath the mulch stays moist longer and is less likely to compact from watering. Weed problems are minimized with a couple of inches of pumice mulch. Pumice does not break down, so does not need to be replaced. Our white pumice can also be color-dyed if necessary.
Pumice as a Packing Medium for storing and transporting tubers, roots and bulbs.
Specialty Growing Applications. Lightweight pumice is ideal for hydroponics, aquaponics, cutting propagation, and other high-efficiency soilless growing applications. We package and distribute a pumice grow media specifically for the soilless growing industry—Ponics Stone™ Grow Media (see left; linked).
Pumice as a Seed Coating. Seed coatings are necessary when the natural state of the seed needs improved so as to be more compatible with precision seeding equipment and practices. The customized seed coatings possible with pumice produce seeds that are ideal in size, weight, shape and uniformity. Because of the highly absorptive nature of pumice, a pumice-blended seed coating can also serve as a kick-start nutrient carrier. Once sown into the soil, pumice also works as a long-term soil conditioner.
Pumice as a Chemical-to-Soil Delivery Medium. Pumice is chemically inert and extremely absorbent, making it an ideal host for delivering useful agricultural chemicals such as herbicides, pesticides, fungicides, fertilizers. And once pumice has given up its chemical rider, it remains to condition and improve the soil.
Ecology Embankments. Designed as an effective and affordable solution to filtering runoff water along roadways, ecology embankments that include pumice gain filtration performance as well as improved soil quality to support vegetation and biomass growth.
Pumice in Rooftop Gardens. A significant amount of the soil needed for rooftop gardening and green-roof applications can be replaced with lightweight pumice. Not only does pumice-soil cut the overall weight load on the roof system, pumice, as detailed above, provides real value to soil function as well.
Pumice Improves Compost. A blend of compost and pumice makes sense on two levels—pumice provides a buffer to the extreme volatilization taking place in the decomposing compost matter and then, once in the soil (as a part of the compost), the pumice provides long-term soil structure. The pumice also improves the moisture and nutrient-holding capability of the soil. [DOWNLOAD THE KNOWLEDGE BRIEF]
REQUEST A PUMICE SAMPLE
If you’d like to run tests and trials using our pumice in your commercial product formulation or industrial process, please contact us at firstname.lastname@example.org with your request. We look forward to answering your questions, helping you select the best grade for your process, or helping you explore the fit of pumice for your needs. PLEASE include your name, your company or organization, pertinent project details, ship-to address, and preferred contact information in the sample request email.
If you’d like a bit of pumice for personal use, we have a nice selection of pumice grades available to purchase via our Pumice Products Store.
TALK TO A PUMICE EXPERT
We know pumice. We’ll be glad to answer your questions, join you in your lab for tests, or simply supply a sample for testing—whatever you need.
SALES: If you need to talk availability, grades or grade blends, logistics, costs...contact Jason Kimberling, Sales Manager, at extension 142 or email email@example.com
RESEARCH: Perhaps you are exploring the possibilities—thinking pumice may fit your particular horticultural or soil improvement need—then we invite you to contact Brian Jeppsen, VP Research and Development, at (208) 766-4777 x111 or email: firstname.lastname@example.org