Superabsorbents, A Water Management Tool For The Busy Gardener

Superabsorbents are water management "tools" that are a valuable aid to landscapers and others in the Green Industry. Because superabsorbents enhance moisture availability they:
Superabsorbents are available in a variety of physical and chemical forms, however, all work in the same fundamental way.

What They Are & How They Work

A superabsorbent is a material that acts like a super-sponge, absorbing and storing hundreds of times its weight in plant available water, releasing it to the plant on demand. As a superabsorbent absorbs water it forms a gel. In addition to the amazing ability of these materials to increase moisture availability, Superabsorbents act to promote aeration and in many other ways to benefit landscapers, growers, and other users.

When water comes into contact with a superabsorbent an electrical repulsion takes place within the particles. When this happens, water is drawn into the particles resulting into a swelling of each particle. At maximum absorption capacity each particle will expand to over thirty times its original volume. When water evaporates or is used by the plant, the material shrinks, returning to the unswollen state. When water is again added, the material will re-swell absorbing the water as described previously.

The absorption capacity of superabsorbents is affected by acidity and alkalinity (pH), conductivity, and other variables that inhibit expansion of the gel particles. The pH of the absorbed fluid should not present a problem in most plant related applications since the pH and the growing environment is normally within the ideal range (six-nine) for optimum absorption. Fertilizers, salts, and other chemicals in the growing environment can, however, cause some reduction in absorbency. Superabsorbents remain effective through thousands of shrink-swell cycles. In the growing environment superabsorbents remain effective for several years. This is more than adequate for most landscaping applications since the plants will have adapted to the natural environment by this time.

Promotes Faster Growth

Most are watered on a schedule or when signs of wilting appear. Such methods do not ensure that the plant has adequate water for optimum growth. In fact, by the time a plant begins to wilt, it has long since stopped growing. Using a superabsorbent allows the plant to obtain water as needed for optimum, uniform growth. There is no slow down due to too much or too little water.

Improves Aeration And Drainage

Oxygen depletion or carbon dioxide build up in the plant root zone is harmful or fatal to a plant. When superabsorbent particles are present in the growing media, they will, upon absorbing water, expand to many times their original volume. This expansion opens, and exercises the growing media by forcing soil particles apart, increasing aeration and improving drainage. Once these particles reach their maximum absorption, excess water flows freely over and around the particles as it would flow over a saturated sponge. "plugging" of the soil is not, therefore, a problem.

A major advantage of superabsorbents is their ability to make use of gravitational water, which is not usually available to plants because it leaches to a depth where it is not plant available. As the water contacts the superabsorbent particles they will swell, absorbing water until they reach saturation.

How To Use Superabsorbents

There are several basic ways to use superabsorbents:

Some examples of typical application methods are:

Transplanting: For transplanting larger plants the superabsorbent is sprinkled evenly into the hole prior to setting the plants or mixed into the backfill. Only a small amount is required, for example one to two ounces per foot of root ball diameter. The plant is then planted and watered as usual, however, watering frequency can often be cut in half.

Smaller plants may be transplanted and shipped with a gel slurry consisting of a superabsorbent and water. Alternatively a thin gel can be prepared and sprayed over the roots. Simply dipping the roots in a superabsorbent gel can double the period a newly installed plant can go without watering.

Amending Media: Media fir bedding flat, potted plants and other applications can be treated with a superabsorbent by mixing it a t a rate of about two pounds per cubic yard of media. Mixing is easier with dry media.

Hydraulic Mulching: Superabsorbents are mixed with water, seed and other additives to promote and speed germination. In addition, the use of a superabsorbent improves fluid flow since the material acts as a lubricant. Superabsorbents are used in hydromulching to promote emergence and growth. Superabsorbents are not appropriate for all applications. Where there is ample rainfall or the area receives adequate, uniform irrigation the use of superabsorbents may not be justified.

Superabsorbents are water management "tools" which offer many advantages for the nurseryman. A superabsorbent can be considered as a "chemical drip irrigation system" providing plants with a supply of moisture which is available on demand- over a prolonged period of time.

Some specific benefits resulting from the use of superabsorbents include:

Superabsorbents are substances which absorb great quantities of water in relation to their own dry weight. When superabsorbent particles absorb water they swell, forming a gel. Virtually all of the water stored in the individual gel particles can easily be withdrawn from the water-swollen superabsorbent particles by plant roots.

Major Applications In Nurseries

A major application for superabsorbents in the nursery industry is to improve the moisture holding capacity of soil and soil-less mixes. In addition, using superabsorbents can increase aeration and drainage. Increased aeration reduces the likelihood of root rot since there is a better opportunity for root gas exchange. The increase in aeration and expansion of the growing media occurs as superabsorbent particles expand. In expanding they push surrounding soil particles apart, loosening the media, increasing pore space.

Superabsorbent expansion can result in a substantial saving of growing media. One yard of media, with a superabsorbent, when watered, may expand to produce five to six additional cubic feet of media. The savings in media cost (approximately 20%) will pay for the superabsorbent: the benefits from using a superabsorbent can then be considered as a free bonus.

Optimum moisture levels are maintained with plants when superabsorbents are used. Consequently, they can grow faster and more uniformly. There is no slow down in growth due to too much or too little water.

Extend Shelf Life
Superabsorbents extend plant shelf life since they permit a given volume of growing media to hold more water. At the same time there is less chance for over-watering because of the increased aeration and drainage. Because the media holds more water, watering frequency can often be cut in half. Reduced watering requirements result in substantial labor savings, especially when hand watering is required.

There are several additional ways to use superabsorbents in addition to incorporating then in the growing media. Superabsorbents can be mixed with water to form a thin gel. Rooted plants are dipped in the gel prior to transplanting. Having water-swollen superabsorbent particles right on the root structures help to minimize transplant shock and increase survival.

Superabsorbents can also be mixed into backfill when transplanting trees and shrubs. Superabsorbent particles absorb gravitational water, the water which would normally drain down through the soil. This increases irrigation efficiency and can reduce watering requirements by 50% or more. In addition to increasing moisture retention, superabsorbents can increase nutrient retention. At a three pound per cubic yard rate nitrogen availability increased by 9%. The increase in nutrient availability is attributed to reduced leaching which is inherent in the proper use of superabsorbents.

Soil amended with Moisture Mizer improves plant growth under conditions where irrigation may be infrequent of irregular.

Use In Propagating Material

Superabsorbents maintain more uniform moisture levels in propagating media. During the rooting of cuttings, adequate moisture levels must be consistently maintained. In many greenhouse installations, however, areas of incomplete moisture distribution can result in drying of the medium and failure of cuttings to root. Moisture Mizer Polymers

Applications

Nurseries

For containerized plants:
Mix 1-2 pounds of medium or small grain Moisture Mizer into a cubic yard of soil/growing media (2/3 to 1 1/3 ounce per cubic foot). Place plants into their containers with the treated soil- ALLOW FOR 15% EXPANSION OF THE SOIL AFTER THE WATERING OR THE PLANT WILL POP OUT OF THE CONTAINER! This expansion will allow a reduction in the amount of media required, and less soil equals less expense.

For individual sizes use the following amounts:

Reduce fertilizer applications by 10-12% due to Moisture Mizer's ability to store and slow-release nutrients. This retention ability plus the cut-back in application amounts reduce the amount of fertilizer lost to leaching. Reduced leaching means less damage to the environment.

Plants treated with Moisture Mizer look better, grow faster, have more blossoms, more root mass, can go twice as long between waterings, have twice the shelf-life, survive transplant shock with less damage, are less likely to attract damaging insects, and have better aeration and drainage than untreated plants.

The reduction in the amount of media required due to the Moisture Mizer's expansion (up to 30 times in volume), and the reduction in fertilizer goes a long way towards defraying the cost of using the polymer. The time spent watering the stock is cut back by 50%, so the employee(s) can be put to work at more profit making tasks.

Nurseries need Moisture Mizer --
it will make them money!