Pumice is an excellent conditioner for poor native soils, improving structure and imparting excellent water and air holding properties.
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 potting media can help meet those critical requirements. Pumice also has application in soilless processes.
Pumice as a Soil Conditioner
Pumice make an excellent soil conditioner, as it is highly porous, giving it excellent water and air holding properties. The advantages of using pumice in potting media and garden soils include:
Holds Vital Nutrients. 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. [ ••• ]
Pumice IS THE PHYSIOCHEMICAL EQUILIVANT OF PERLITE
A 1992 study1 done by the Department of Horticulture at the University of Illinois found the physiochemical properties of pumice—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, ecology embankments, reclamation projects, and high-value crops.
PUMICE AIDS TURF MANAGEMENT
For the same reasons detailed above, pumice is a high-performance addition to poor native soils when preparing a quality seed bed for new turf areas. Pumice-enhanced soils can solve issues with native soils that are susceptible to compaction or have a poor water and nutrient retaining structure. [ ••• ]
Reclamation and Runoff Mitigation with Pumice-charged Soil
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. [ ••• ]
Pumice for Soilless Growing Applications
Lightweight pumice is ideal for hydroponics, aquaponics, cutting propagation, and other high-efficiency soilless growing applications.
IDEAL FORM FACTOR
The lightweight, foamed-glass stone of a pumice particle has the ideal form for soilless grow media. [ ••• ]
DRAINAGE RATE CONTROL
Pumice grow media is available in a variety of sizes and grade blends—providing growers with greater control over drainage and water retention rates. [ ••• ]
Pumice Improves Compost
A blend of compost and pumice makes sense on two levels. One, during the composting process, pumice provides a buffer to the extreme volatilization taking place in the decomposing compost matter. Two, pumice-blended composts provide long-term soil structure improvement and continues to contribute to the moisture and nutrient-holding capability of the soil.
IMPROVING THE COMPOSTING PROCESS
Research into pumice as a composting amendment definitively shows the value provided by pumice to the composting process and as a tool to meet the challenges presented by various feedstocks. [ ••• ]
CONTRIBUTES LONG-TERM TO SOIL PERFORMANCE
Compost is short-lived, and if compost is also being counted on to improve the structural and functional profile of poor soil (and it usually is), that benefit disappears as the composted organic matter is broken down and consumed. [ ••• ]
Other Horticultural Uses for Pumice
Along with the applications detailed above, pumice is also used in the following horticultural processes and products.
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 and easy-to-bond 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 readily 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.
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 and structure as well.
Pumice as a Packing Medium for storing and transporting tubers, roots and bulbs.
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.
RECOMMENDED GRADES FOR HORTICULTURAL APPLICATIONS
Soil Amendment / Conditioner
1/8 Fines MN | 3/8 x #8 MN | 3/8 x #8
Soilless Grow Media
3/4 x 5/16 | 5/16C | 3/8 x #8 | #10 | 8/12B | 1/8 Fines MN
1/8 Fines MN
3/4 x 5/16 | 5/16C
NOTE: The grades selected above are typical and representative. Please contact us regarding your product, project, or process for help to determine the ideal grade or grade blend.
GET A PUMICE SAMPLE
If you’d like to sample a pumice grade (or several), we have a nice selection of stock pumice grades available to purchase in small quantities via our Pumice Products Store.
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.
We know pumice. We’ll answer your questions, help determine the ideal grade for your needs, get you sample grades for testing, or help figure out the logistics for getting pumice to you—whatever’s needed.