Kiowa Conservation District
303-621-2070 ext. 101
Helping People Help The Land in Elbert County Colorado
One pound of polymer will absorb 48 gallons of deionized water (pure water, rain water, or snow melt), or 20-30 gallons in normal soils, depending on salt content. Various tests with flowers and other plants show the ideal rate for optimum growth is one part wet polymer to four parts soil.
You can apply it wet or dry. Dry crystals are easier to work with, but take care to ensure the crystals are watered enough to charge them fully with water. It's best to distribute the polymer evenly through the soil. (See other ideas for shrub and tree plantings.)
For large quantities of potting soil, or backfill around trees or shrubs, use 1 1/2 to 2 pounds of polymer per cubic yard of soil (which is about 200 gallons of soil).
For small quantities use 1/2 teaspoon dry crystals per quart of soil.
When applied dry, leave room in the planting hole or flowerpot to accommodate the 20% swelling volume of the crystals.
This works best for small applications such as repotting houseplants and planting small trees and shrubs. Mix polymer crystals with water and allow to stand 60 to 90 minutes.
Application rates for polymer
Dry Crystal Method
Using the above rates, mix dry polymer crystals thoroughly with lowest third of potting soil. To prevent swelling crystals from pushing soil from the pot, fill only to within 1" of the rim. Plants must be thoroughly watered twice within 3 hours to ensure maximum hydration.
Mix hydrated gel using the rates shown for houseplants. Fill your pot 1/5 full of potting soil, then layer in correct amount of gel for pot size. Place plant root ball in gel, then fill with soil to top.
Mix correct amount of gel evenly throughout the lowest third of the potting soil. This is because in routing watering, the water tends to flow quickly to the bottom of the pot before the crystals at the top have to re-hydrate fully.
Pencil Method for Existing Potted Plants
Insert a pencil 3-4 places around the plant to four-fifths the depth of the pot. Divide the correct amount of dry crystals for the pot size evenly among these holes. Reinsert pencil to push crystals to the bottom of the holes. Water twice thoroughly within 3 hours.
Use a "whirlybird" hand fertilizer spreader or drop spreader to disperse the polymer evenly over the ground before rototilling to appropriate depth. Increase application rate roughly 10% over sloped areas. Save one pound of polymer per 1000 square feet to spread over the top of the soil before sodding.
Make sure all polymer is placed underground because hydrated crystals breakdown in sunlight. If you are planting native grasses by drilling, you'll need 5 to 30 pounds per acre. If you are broadcasting, you should at least double that rate.
Watering intervals can be extended approximately one day for each 7 1/2 pounds of polymer per 1000 square feet, given worst case evapotranspiration rates for Colorado. For example, 15 pounds of polymer normally stores 1/2" of extra water (two additional days between watering) and 30 pounds stores 1" of extra water (four additional days between watering).
Avoid a Soft Lawn
Never use more than five pounds of polymer per tilled inch per 1000 square feet. Using this formula, 20 pounds must be tilled in 4" deep and 30 pounds tilled in 6" deep.
For bareroot and potted nursery plants, store all bareroot stock in hydrated polymer while planting. For one gallon of hydrated polymer, use 16 teaspoons with one gallon of water.
Then, when you are ready to place the bareroot plant in the ground, mix 1/2 cup of the hydrated polymer into the back fill as close to the root system as possible. In large plantings, you can also place the polymer at the bottom of the hole. If your planting is remote and less likely to receive irrigated water, you may double the amount of polymer for each plant.
For additional water storage, use one ounce of non-hydrated polymer per gallon of your desired water storage capacity. Thus, to store 5 gallons of water per plant, use 5 oz. of polymer. It's best to include one-half cubic foot of backfill, in addition to the root ball volume for each ounce of polymer. Water each plant with the desired amount of storage water. A small depression over the planting hole can catch naturally occurring water.
Drop in polymer with seed 3-6 oz. per 100 feet of seed furrow (8 teaspoons per oz.).
Spread polymer evenly over the top, along with any other soil amendments used. Use polymer at a rate of one pound per 100 square feet. Work into the soil by rototilling or turning over with a shovel.
Typical rates for seed row or other banded applications range from 5-30 pounds of polymer per acre, with median rate of 15 pounds.