Horti-Perl horticultural perlite is a unique volcanic mineral which expands up to 13
times its original volume when heated to about 1700 degrees F. During heating the rock
expands to form an extremely light-weight, sterile, and sharp white material. Each
expanded particle contains tiny air cells and is covered with multiple cavities thus
creating a unique and valuable structure for rooting and growing. With its inherent
sharpness, Horti-Perl provides superior particle interference, thus creating excellent
aeration and soil mix yield. With its extensive surface area, it also holds and releases
sufficient moisture for optimum plant growth and development. Horti-Perl is odorless,
chemically neutral, resistant to shrinkage and light in weight. This lightweight property
allows for the custom blending of peat-perlite soils which weighs as little as 180 lbs.
per cubic yard vs. 3,300 lbs. per cubic yard for natural soil. Horti-Perl is used in
conjunction with most organic amendments, e.g. peat moss, bark or sawdust, and is
available in several grades: HP-4, HP-3, HP-2, HP-1, #27, and #31-T. This wide range of
sizes make it possible to adapt soil to a wide variety of plants in all stages of growth
from propagation to large containers.
Horti-Perl #4 - Coarse, Screened, Propagation Grade
The coarsest grade of propagation perlite available; provides rapid drainage, and high air
space after drainage. Ideal for propagation of cuttings of almost every variety of plant
when used alone or with peat moss in various proportions. Also used extensively in bedding
plant and ground cover media and in container mixes for Azaleas, Gardenias, Camellias,
Ferns, and tropical plants.
Horti-Perl #3 - Coarse, All-Purpose Grade
Unscreened version of HP-4 possessing predominately coarse with some finer particles for
those applications requiring additional water retention.
Horti-Perl #2 - Coarse, Intermediate Grade
Smaller top size than HP-4 or HP-3 but comparatively uniform in particle size with minimum
fines. Used in ground cover, bedding plant and plug applications.
Horti-Perl #1 - Coarse Sand Size
Still finer top size than HP-2 with more fines; ideal where additional moisture retention
is desired, e.g. cell packs or in-ground application.
Horti-Perl #27 - Fine Sand Size
This relatively uniform, fine perlite is roughly equivalent in size to the Redondo Beach
Fine Sand used in the original U.C. mix. It's uniform particle size provides sufficient
particle interference to provide good aeration and drainage while retaining considerable
extra moisture. #27 is an economical and long lasting amendment for bedding plant soils
or landscape soil incorporation.
Horti-Perl #31-T - Intermediate, Screened Grade
A very clean, screened perlite, intermediate in size to HP-4 and HP-1. Ideal substitute
for vermiculite in seed mulching and plug tray media.