THE "POWER OF PERLITE" This week’s tip is Perlite, what it is, what it does. What it is:
Perlite is a unique volcanic material that starts as crude perlite rock. Crude perlite contains from two to six percent combined water, causing it to expand from four to twenty times its original volume during the rapid heating of volcanic activity. The perlite is rapidly heated to temperatures of 1600 to 1700 degrees F. and it pops like a kernel of popcorn.
When expanded, each granular snow-white particle of perlite is sterile with a neutral pH and contains many tiny, closed cells or bubbles. The surface of each particle is covered with tiny cavities that provide an extremely large surface area. These surfaces hold moisture and nutrients and make them available to plant roots. In addition, because of the physical shape of each particle, air passages are formed which provide optimum aeration and drainage. Because perlite is sterile, it is free of disease, seeds and insects.
Perlite has been used for many years throughout the world for soil conditioning and as a component of growing mixes with materials such as peat moss or bark. Extensive studies have shown that the unique capillary action of perlite makes it a superior growing medium for hydroponics’ cultures, turf and lawns, and around shrubs, trees and landscaping.
What it does: Propagation and Seed Cultivation: Commercial growers and hobby gardeners have found that perlite is an ideal medium for rooting cuttings. Through the use of cuttings rooted in horticultural perlite, the time to first production may be reduced by as much as 40%.
Perlite mixes of fine perlite alone can be used as a seed-starting medium because of the ease of maintaining uniform moisture and temperature levels. Perlite’s bright white color makes it particularly effective as a seed cover offering protection against bright sunlight and high radiant energy as well as resistance to surface moss or algae growth. In addition, perlite’s white color reflects light up under the plant foliage, which further enhances growth.
Testing done in India has shown that when seeds are sown with small quantities of fine perlite in field crops, there is a much higher rate of germination and a measurable increase in yields.
Plug Production/Transplants: Commercial plug plant production in greenhouses showcase perlite’s role in water and nutrient conservation. Water retention by horticultural perlite is not an indiscriminate action. The amount of water absorbed on the surface of perlite is a function of particle size. Coarser perlite particles absorb less water than the finer grades—thus the amount of retained moisture can be regulated by the particle size.
Perlite’s ability to cling to roots and root hairs and the friable nature of a perlite mix reduces transplant shock and increases survival rates.
Reduced production time, conservation of water and nutrients, reduced labor and shipping costs and increased survival rates all confirm horticultural perlite’s long and enviable record of performance throughout the world.
Composting: Recycling as a result of shrinking landfill disposal areas has increased interest in composting in home gardens and by commercial enterprises and municipalities. Studies at Cook College of Rutgers University reveal that additions of perlite to compost piles speeds decomposition of leaves, grass clippings and other yard waste. In addition, the use of perlite reduces the amount of labor required to periodically turn piles to ensure proper aeration. When composting is completed and the compost is put to use, the perlite will continue to perform for many years as it lightens and aerates the soil while increasing its water-holding ability.
Hydroponics Culture: The fastest growing application for perlite in the horticultural field is in hydroponics culture. Perlite exhibits a unique capillary action in that nutrient-rich water can be drawn up from a reservoir through a fine perlite-based growing medium at the rate that is required by a plant. As a result, plants grown in perlite do not suffer from over watering or under watering.
Hydroponics tomato crops grown in perlite have produced average yields 7% higher than tomatoes grown in rock wool. Currently throughout the world, many table vegetables are being grown in hydroponics grow bags. Melons are being grown in Florida. In Holland and the U.S., commercial cut flowers, strawberries and orchids are being grown in 100% hydroponics perlite containers.
Turf and Lawns: No grass is more highly stressed than stadium turf and golf greens. These are subject to the whims of nature as well as constant foot traffic and resulting compaction. Horticultural perlite can provide an easy solution to this problem. When turf is renovated with perlite, excess water will not pond, yet an optimum amount of water will be retained for proper growth. Additionally, turf will be lush and green while the soil will remain soft for an extended period of time.
For the landscaper or home gardener, the addition of fine and medium grades of perlite will promote drainage and eliminate soil crusting in heavy clay soils. Plant roots will more easily penetrate the perlite/soil growing media. Most importantly, the lawn will hold much more water and require less watering.
Interiorscape and Container Growing: Not only does the use of perlite lighten the soil of container plantings - where weight can be a factor - but it also adds the nutrients previously mentioned and prevents leaching of the soil. A half and half mixture of perlite and peat moss provides a soil-less mix that is both lightweight and nutrient packed. Shrubs, Trees and Landscaping: The addition of fine and medium grades of horticultural perlite is very effective in growing shrubs and trees and in other landscaping applications. Besides retaining water, which is vitally important in light of the growing shortage of water in many parts of the world, perlite also aerates the growing medium. Since landscaping applications are usually permanent in nature, fine and medium grades of horticultural perlite are the ideal choice because they do not rot or otherwise decompose, and perform their water conservation/aeration roles for the life of the planting.
This is "The Power of Perlite"
 See you next week - "Keep Those Hands Dirty"!
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