Method for decreasing hydrophobicity of peat, bark and rockwool in soilless mixes used for plant growth, promoting easier, faster and more even watering of such mixes without plant injury and providing activity for future watering

Abstract

A novel and improved method for relieving hydrophobicity of peat moss, bark and rockwool used in horticultural media for plant propagation using an effective level of a composition consisting of certain copolymerized alkane oxides is described. A more effective method of delivering these materials based on a composition of hydrous, amorphous silica using the compositions of the present invention is described.

Description

BACKGROUND OF THE INVENTION

Products normally used in the production of soiless mixes for greenhouse crop production are often water repellent (hydrophobic) in nature. The hydrophobic surface chemistry of these materials, particularly those from organic sources, is somewhat peculiar and does not relate well to other surfaces. Such components as sphagnum peat moss, hypnum peat moss, reed-sedge peat, composted bark and rockwool which are used in such growing mixes to increase their water holding capacity often become very difficult to wet defeating the purpose for which they were originally intended. The difficulty in wetting increases as the mix dries out normally in storage after preparation or when used to pre-fill pots and flats by the grower and stored for some time before use. This situation presents many problems to the grower as getting the mix evenly wetted is of paramount importance to the healthy growth of the plants or seeds which are grown in the mix. Without water the plants will die.

A possible answer to this problem is to add an appropriate surfactant to the mix to reduce surface tension between the applied water and the hydrophobic mix components. The use of materials currently in commerce is not entirely satisfactory. Relatively high rates of these materials are required to get good wetting properties of the mix and at such rates can be injurious to crop growth. Furthermore, the conventional dry formulations of these materials based on corn cob grits and vermiculite do not work well as the surfactant must first be dissolved from these carriers and bind to the hydrophobic surfaces of the peat, rockwool or bark before they become activated. Consequently, several waterings are normally required before they become active. Furthermore there is an environmental concern as the described compounds contain nonyl-phenol ethoxylates or other mono or di-alkyl phenol ethoxylates. The conjenors of such compounds are known to bioaccumulate in the biosphere with deleterious effects on fresh water crustaceans and their use has been banned in many countries.

The majority of the surfactants currently discovered and developed have been designed to give fast wetting as they are used as cleansers, soaps and detergents. The problem with greenhouse mixes is that fast wetting is not necessarily desirable as they would have to be applied with each watering. What is more desirable is rewetting of the peat or other substances following treatment with a surfactant giving residual activity.

Unfortunately many such surfactants can also have biological activity. They can, in fact, be detrimental to plant growth and many are actually fatal and can act as herbicides. Others have other biological activity and can cause death of insects. Many of these compounds we have previously tested were found to interfere with seedling growth. I have shown earlier that such materials act by disrupting membrane integrity as the hydrophobe bonds to the phospholipid Membrane of the cell wall. Others can act as plant growth regulators and while their use may be beneficial in achieving certain results they cause undesirable effects in greenhouse crop production.

Furthermore, if the selected surfactant is to remain active in the mix beyond the initial watering it is desirable that the hydrophobe of the surfactant bond tightly to the hydrophobic mix component and not leach out when plants are repeatedly watered.

In addition, it is highly desirable that such a surfactant be compatible with fertilizers and other water soluble chemical charge stocks used in preparation of the final horticultural mix.

Although such materials may be applied as a liquid it is also desirable that they may be presented in a dry formulation for ease of application and use by the grower. This creates an additional problem in that most carriers commonly used such as vermiculite, corn cob grits, clay and so forth also absorb the surfactant or tightly bind them to their surfaces making it necessary for the surfactant to first be dissolved from the carrier before it can become active.

Although there are over 4000 surfactants currently in commercial use the discovery of such a surfactant for use in soiless mixes such as root media is therefore not a trivial problem as it must meet certain specific and difficult criteria, namely:

(1) Be compatible with the surface chemistry of peat, rockwool and bark,

(2) Safe for plant growth, particularly seed germination and seedling growth,

(3) Bind tightly to mix components so that it is not leached from the matrix following watering and have residual activity for a full normal cropping season.

(4) Give not only fast initial wetting but also and more importantly rewetting after application to the mix components,

(5) Be compatible with fertilizers and other chemical components and

(6) Have ease of application and be effective in both a liquid and solid formulation.

Surprisingly we have found that certain surfactants belonging to the general class of polyoxyalkylenes meet conditions 1, 2, 3 and 4 and that specific formulations of some members of this class meet conditions 5 and 6. Furthermore, these materials are superior in all six respects to known products used for this utility and which are now commercially available.

Surfactants of this type are described in U.S. Pat. Nos. 4,764,567, 3,086,118, 2,677,700 and 2,674,619. These patents teach us the preparation and use of such materials as surface active agents for use as cleansers and detergents and as wetting agents in the textile, rubber, paper, lacquer, leather and like industries but no mention is made of their use in soils or soiless horticultural media nor in their interaction with living organisms nor for general applications in the Agricultural or Horticultural industries. Furthermore, despite the age of these patents their use for such utilities is unknown.

To date, no correlation has been shown between a chemical structure of a particular class of surfactants and its phytotoxicity (in this case crop safety) to seed germination and plant growth. Indeed the converse is true with most surfactants known to be injurious to plants. This is not surprising as surfactants in general because of their solubilizing and dispersing nature will dissolve plant cuticles, interfere with plant membranes and generally disrupt membrane integrity in tender plant tissue as their hydrophobes will bond to such lipophyllic organs found in plants such as emerging roots, root hairs, radicles and hypocotyls. The discovery of such surfactants which will maintain good wetting properties in the surrounding media without interfering with plant growth is therefore surprising and unusual.

SUMMARY OF THE INVENTION

This invention relates to a novel method for relieving hydrophobicity of components such as peat, bark, rockwool and the like used in horticultural mixes for their water holding capacity and making them easy to wet without causing plant injury at the recommended rates and with a very high margin of crop safety. Of specific interest are polyoxyalkylenes of reacted ethylene and propylene oxides and ethoxylated, propoxylated alcohols with having a molecular weight greater than 2000. Particular compositions described in the invention have been developed which overcome the inherit problems of the parent chemistry in being compatible with fertilizers and other like components used in crop production. A particular composition which is based on the use of hydrous, amorphous silica, a non-metallic oxide, in combination with such polymers of ethylene and propylene oxides having a molecular weight greater than 2000 has been shown to be particularly effective for use in soiless mixes consisting of peat, rockwool, bark and the like and overcomes problems with existing products based on vermiculite, corn cob grits and other similar materials now commonly used.

In accordance with this invention the above-desirable effects may be obtained by applying to soiless mixes such as root media at preparation, or during the course of crop production, of an appropriate amount of certain surfactants, represented in Formulas (I), (II) and (II). Preferred compounds are those represented in Formulas (II and III).

HO(CH2CH2O)a-{CH2CH(CH3)O}b-(CH2CH2O)cH Formula I Where b=% and ranges from 10-20 and a+c=MW Ethylene Oxide and is 1900-2000. HO{CH(CH3)CH2O}a-(CH2CH2O)b-{CH2CH(CH3)O}cH Formula II Where b=% and ranges from 10 to 80 and a+c=MW of Propylene oxide and ranges from 1700 to 3100. CH3(CH2)a-O-{CH2CH(CH3)O}b-(CH2CH2O)c-OH Formula III Where a=3, 7, 9 or 11; b=4 to 12 and c=8 to 16.

EXAMPLE 1

EVALUATION OF SELECTED TEST COMPOUNDS FOR RELIEVING HYDROPHOBICITY OF PEAT

Products for evaluation were tested by preparing solutions of various concentrations, filling a 90.times.15 mm round petri dish with the test compound and floating a dried 40.times.8 mm compressed peat pellet on top of the test solution. The time to wet the pellet completely was recorded in minutes and seconds. Each test solution was replicated three times. Following the initial test the pellets were set aside for drying for use in the test to determine rewetting. Rewetting was determined by placing the air-dried peat pellets in a 90.times.15 mm petri dish filled with deionized water. Again time required to obtain full hydrature was measured and recorded in minutes and seconds. A control consisting of deionized water was used as a standard to which all other compounds were compared in each test. The numerical values obtained for several representative compounds of the invention and standard compounds used for this purpose are given in Table 1a, Table 1b, and Table 1c. Values are the means of three replicates. Values for the control are dependent upon humidity, temperature and state of the peat used in producing the pellets and are included in each example for comparison. In all cases a standard (Compound 101 or Compound 168) was also included so that a comparison could also be made of surfactant activity between experiments.

TABLE 1a______________________________________COMPOUNDS OF FORMULA II. Average TimeCom- Rate (Minutes:Seconds)pound (ppm) Initial Wetting Rewetting______________________________________Control 0 14:30 16:00102 25% Ethylene oxide 250 7:30 7:00 capped with 2500 MW 500 6:30 6:30 Propylene oxide 1000 6:00 4:30101 10% Ethylene Oxide 250 6:30 5:30 capped with 3100 MW 500 6:00 4:00 Propylene oxide 1000 5:30 3:30105 45% Ethylene Oxide 250 7:00 6:30 capped with 2500 MW 500 6:00 6:00 Propylene Oxide 1000 5:30 4:00106 80% Ethylene Oxide 250 8:30 6:00 capped with 2500 MW 500 6:30 4:00 Propylene Oxide 1000 5:30 3:00188 10% Ethylene Oxide 250 7:00 6:30 capped with 2500 MW 500 5:30 4:45 Propylene Oxide 1000 6:00 3:30189 20% Ethylene Oxide 250 7:15 7:00 capped with 1700 MW 500 6:00 6:30 Propylene Oxide 1000 5:00 4:45______________________________________

All of the compounds listed were effective in reducing hydrophobicity of peat with compound 101 giving the best response wed by compound 102.

TABLE 1b______________________________________COMPOUNDS OF FORMULAS II and III.Com- Time (minutes)pound rate (ppm) Wetting Rewetting______________________________________Control 0 42:00 34:00101 15% Ethylene oxide 250 18:30 9:30 capped with 3100 MW 500 17:30 7:00 Propylene Oxide 1000 11:30 3:30149 1,2 Propanediol; 250 24:00 9:30 Oxirane, methyl- 500 20:00 8:30 polymer with Oxirane 1000 15:00 4:30168 C4 Alcohol; 250 21:30 7:30 Propoxylated (7-9 Mol); 500 17:30 7:00 Ethoxylated (9-11 Mol) 1000 10:30 3:00151 C10-C12 Alcohols; 250 21:30 8:30 Propoxylated (5 Mol): 500 19:00 7:30 Ethoxylated (10 Mol) 1000 12:30 4:00190 C8 Alcohol; 250 20:30 9:00 Propoxylated (4-6 Mol) 500 17:30 7:00 Ethoxylated (8-12 Mol) 1000 12:00 4:00______________________________________ TABLE 1c______________________________________COMPOUNDS OF FORMULAS I and III.Com- Time (Minutes:Seconds)pound Rate(ppm) Wetting Rewetting______________________________________Control 0 37:30 34:00168 C4 Alcohol; 250 18:00 7:00 Propoxylated (7-9 Mol) 500 16:00 6:30 Ethoxylated (9-11 Mol) 1000 11:00 3:00154 MW 1950 Propylene 250 26:30 9:30 oxide; 20% Ethylene 500 19:30 6:30 oxide 1000 15:30 4:00155 MW 1950 Propylene 250 26:30 11:00 oxide; 10% Ethylene 500 19:30 5:30 oxide 1000 16:00 3:00______________________________________

All three classes of compounds were effective in reducing hydrophobicity of peat moss. In general the selected compounds of Formula III were superior to the selected compound of Formula II. Compounds of Formula I had good properties but in general were not as effective as those of Formulas II and III.

In the next test, selected compounds of the present invention were tested to show their superiority over materials currently availible. The numerical values obtained are summarized in Table 1d.

TABLE 1d______________________________________Comparison of selected compounds of the invention to productscommercially available in the industry for this utility. Rate Time (Minutes)Compound (ppm) Wetting Rewetting______________________________________Control 0 26:30 22:30101 10% Ethylene Oxide 250 14:00 6:30 capped with 3100 MW 500 12:00 4:00 Propylene oxide 1000 9:30 2:30102 20% Ethylene Oxide 250 19:30 7:30 capped with 2500 MW 500 15:00 5:00 Propylene Oxide 1000 12:00 3:30168 C4 Alcohol, Prop- 250 18:00 6:00 oxylated (7-9 Mol); 500 17:00 5:00 Ethoxylated (9-11 Mol) 1000 12:00 3:30151 C10-12 Alcohol, 250 17:30 9:30 Propoxylated 5 Mol; 500 14:30 8:00 Ethoxylated 10 Mol. 1000 11:30 4:30154 MW 1950 Propylene 250 18:00 15:00 Oxide; 20% Ethylene 500 14:30 13:15 Oxide 1000 11:30 4:00A. 2,4 diamlyphenol 9 250 11:00 10:45 ethoxylate 500 10:45 6:50 1000 10:35 5:15B. Nonyl Phenol 9 250 12:00 19:10 ethoxylate 500 10:00 9:00 1000 9:30 7:30C. 50% Nonyl Phenol 9 250 18:00 18:15 ethoxylate; 50% 500 12:00 10:00 Tall Oil Rosin 1000 8:30 8:30 ethoxylates______________________________________

The selected compounds; numbers 101, 102, 168 and 151 were superior in performance in terms of rewetting to the current products available as given by Compounds A, B and C while Compound 154 was superior to Compound C.

EXAMPLE 2

REDUCTION OF HYDROPHOBICITY OF COMPOSTED BARK BY SELECTED MEMBERS OF THE PREFERRED COMPOUNDS

Reduction of hydrophobicity for composted bark was tested in a manner similar that for Peat. Composted bark was obtained from a commercial manufacturer, sized to particles less than 200 mm using an ASTM standard number 10 Sieve. Samples of the dried bark were then treated with the appropriate level of the preferred compounds, air-dried to 18-20% moisture content following which 200 cc of each sample were placed in a 60.times.130 mm tall cylinder (percolation tube) to which a screen had been affixed at one end to hold the sample in place. The percolation tube was tapped several times to insure even settling of the samples. The tube was next secured to a ring stand by means of a clamp in an upright position and a 600 ml graduated beaker was placed under the bottom to collect any effluent. Next 200 ml of distilled water was added slowly to the top of the tube and the effluent collected and measured in the beaker below. The ml of water retained by the 200 cc sample was recorded. The sample was then removed from the tube, broken apart and examined visually to determine the % of the bark that was wet. Results for this test are given in Table 2.

TABLE 2______________________________________Reduction of Hydrophobicity of bark by various selectedcompounds. Values are the means of two replicates. ml of 200Com- Rate retained bypound (ppm) 200 cc of mix. % Wet______________________________________Control 0 25 10101 10% Ethylene Oxide 250 65 60 capped with 3100 500 90 85 MW Propylene Oxide 1000 95 100168 C4 Alcohol; Pro- 250 90 80 poxylated 7-9 Mole; 500 100 100 Ethoxylated 9-11 Mole 1000 105 100151 C10-12 Alcohol; 250 85 80 Propoxylated 5 Mole; 500 95 95 Ethoxylated 10 Mole. 1000 100 100154 20% Propylene Oxide 250 50 50 1950 MW Ethylene 500 65 75 Oxide 1000 85 85______________________________________

EXAMPLE 3

EVALUATION OF SELECTED COMPOUNDS IN REDUCING HYDROPHOBICITY OF ROCKWOOL

To evaluate the effect of compounds on reducing hydrophobicity of rockwool, solutions of various concentrations were prepared and 500 ml placed in a 600 ml beaker. Next, 50.times.50.times.80 mm blocks of a rockwool used for horticultural purposes and obtained from the manufacturer were floated on the surface. The time required for the sample to sink into the test solution was recorded following which the samples were removed, drained to remove excess liquid and dried in a microwave oven with frequent turning to insure even distribution of the test solution. The samples were then left for 24 hours following which they were placed in a similar manner in beakers containing distilled water and the time to sink remeasured. Results for selected compounds are shown in Table 3.

TABLE 3______________________________________REDUCTION OF HYDROPHOBICITY IN ROCKWOOL USED FORHORTICULTURAL PURPOSES BY VARIOUSSELECTED COMPOUNDS. Rewetting Initial Wetting TimeCom- Rate Time to Sink; to Sink;pound ppm Min:Sec Min:Sec______________________________________Control 0 3:30 3:30101 10% Ethylene Oxide 125 1:45 0:25 capped with 3100 MW 150 1:50 0:20 Propylene Oxide 300 0:50 0:10102 15% Ethylene Oxide 125 1:50 0:35 capped with 2500 MW 150 1:50 0:40 Propylene Oxide 300 1:30 0:30168 4 Carbon Alcohol 125 1:30 0:30 Propoxylated (7-9 Moles) 250 1:45 0:30 Ethoxylated (9-11 Moles) 300 1:00 0:25151 10-12 Carbon Alcohols 125 1:30 0:35 Propoxylated (5 Mol); 250 1:25 0:30 Ethoxylated (10 Mol). 300 0:50 0:30154 20% Ethylene Oxide; 125 2:00 0:45 1950 MW Propylene 250 1:45 0:35 Oxide. 300 1:30 0:30______________________________________

One of the preferred compounds (10% Ethylene Oxide Capped with 3100 MW Propylene Oxide: #101) was next evaluated in a pilot plant study under the manufacturers conditions to determine its effectiveness in comparison with the surfactant which was currently in use (Nonyl phenol 9 ETO). Surprisingly, in addition to its superior performance and crop safety this product also had advantages over the previous technology in that it was much more stable under the conditions of the manufacturing process at one third the rate of the currently used compound and resulted in a substantial gain in the acceptable product as reflected by the percent loss following each batch. The results for this study are given in Table 4.

TABLE 4______________________________________PERCENT NOT ACCEPTABLE (LOSS) AS MEASURED BYWETTING PROPERTIES FOR TWO SURFACTANTS ATDIFFERENT RATES USED IN THE MANUFACTURE OFROCKWOOL PRODUCTS FOR HORTICULTURAL USE. Nonyl Phenol 9ETO Compound 101Batch 900 PPM 300 PPM______________________________________A 28% 5%B 31% 8%C 27% 8%______________________________________

EXAMPLE 4

IMPROVED CROP SAFETY OF COMPOSITIONS OF THE PRESENT INVENTION OVER EXISTING COMMERCIAL STANDARDS

Selected Compounds from those described previously were next evaluated for their crop safety. The most intimate contact that a growing plant can have and the method which most tests a chemicals interaction with sensitive plant processes is exemplified in the following test procedure. The method depends upon seed germination where the basic metabolic pathways are all in early development as well as both cell enlargement and mitotic processes for new cell growth. In addition the chemical is in intimate contact with the seed and newly developing plant tissues without the buffering effect of soil or the surrounding media. The procedure for the test is as follows: A disc of Whatman's #1 Filter Paper is placed in a 90.times.15 mm Petri dish. Solutions of appropriate concentrates are prepared and a sufficient quantity of the test solution is added to each petri dish so that the filter paper is completely saturated. Any excess liquid is drained off to prevent saturation and anaerobes in the germinating seed. Next 10-12 seeds of Impatiens sultania, cv. White Elfin (a species and cultivar with known sensitivity to surfactants) are sown on the filter paper and the glass (or appropriate plastic) dish cover added. The covered dishes are next placed in a growth room with a 12 hour photoperiod with temperature maintained at 20 C. Hydrature within the petri dish is maintained by adding distilled water as need to support plant growth during the course of the experiment. Seed germination and seedling growth are monitored throughout the course of the experiment with data taken at 7 and 14 days after sowing. Morphological anomalies are recorded according to the following scale:

5=no effect/same as control

4=10-15% inhibition of seedling growth: marginally acceptable. hypocotyl and radicle development normal. Seedling expected to produce a normal plant.

3=20-30% inhibition of seedling growth; unacceptable.

2=50% inhibition: radicles emerge, some cell division, root caps may be brown, necrotic or dead.

1=75-90% inhibition of growth; seeds germinate but radicles do not continue mitosis.

0=Seedling death, failure of seed germination

Results for selected compounds are given in Table 5. TABLE 5______________________________________Effects of various surfactants on Seedling Growth andDevelopment of Impatiens sultania, cv.White Elvin. Radicles 7 days;hypocotyls 14 days. 0 = no growth: 5 = best.Com- Rate Plant Growth Responsepound (ppm) Radicles Hypocotyls______________________________________Control 0 5.0 5.0101 10% Ethylene oxide 100 5.0 5.0 capped with 3100 MW 250 5.0 5.0 Propylene oxide. 500 4.5 5.0 1000 3.0 3.5 1500 3.0 3.0B. 2,4 diamyl phenol 9 100 3.5 3.5 ethoxylate 250 2.0 2.5 500 2.0 2.5 1000 1.0 1.0C. 50% Nonylphenol 9 100 2.5 3.0 ethoxylate and 50% 250 2.0 2.0 tall oil ethoxylates 500 1.0 2.0 1000 0 0154 1950 MW Propylene 250 5.0 4.5 Oxide:20% Ethylene 500 4.0 3.5 Oxide 1000 4.5 3.5102 20% Ethylene Oxide 250 5.0 5.0 capped with 2500 MW 500 5.0 5.0 Propylene Oxide. 1000 5.0 4.0 0168 4 Carbon Alcohol, 250 5.0 5.0 Propoxylted(7-9 Mol), 500 4.0 4.0 Ethoxylated(9-11 Mol). 1000 3.5 3.5151 10-12 Carbon Alcohol 250 5.0 5.0 Propoxylated(5 Mol); 500 4.0 4.0 Ethoxylated(10 Mol). 1000 4.0 4.0______________________________________

Examples of the preferred chemistry and their formulation on amorphous silica were next evaluated in a greenhouse soiless mix for plug production of selected crop species known to be susceptible to wetting agent injury. "Plug production," the practice of germinating seeds in tiny capsules containing the soiless media for subsequent replanting into larger containers, is a standard practice in the industry but is particularly appropriate for demonstrating the effectiveness and safety of the compound as the seed and germinating seedling is grown in a very small ecosystem. The preferred compound and formulation together with other selected materials used as standards was incorporated into the mix at the preferred rate of 3 ounces/cubic yd and at rates of 6 and 9 ounces/cubic yard to demonstrate crop safety over existing materials.

None of the compounds of the present invention caused injury to any of the species tested: Impatiens, Begonia, Poa pratensis, Celosia, Lycopersicum, Coleus, Allium or Alyssium at three times the effective use rate of 3 Ounces per cubic yard of mix. The commercial standards were safe to these crops at 2 times the effective use rate to all of the species tested but not to Impatiens, allysium and begonia at three times the recommended effective use rates.

EXAMPLE 5

REDUCTION TO PRACTICE UNDER COMMERCIAL CONDITIONS

To reduce the present invention to practice selected compounds of the present invention were evaluated in cooperation with a commercial manufacturer of soiless mixes.

Two of the selected compounds (#101; 10% Ethylene oxide propoxylated with 3100 MW Propylene oxide and #168; a 4 carbon alcohol; propoxylated 7-9 mol and ethoxylated 9-11 Mol) were prepared as 0.33% solutions and 15 ml of this solution applied to 5 g of "peat moss soiless mix" and mixed for 30 seconds. The product which the manufacturer was currently using (#158: 2,4 diamyl phenol ETO 9) was included as a standard and applied in a similar manner. The control received an equivalent amount of water containing no surfactant and was manipulated in a similar fashion. Following application the treated materials were dried to 10% moisture and evaluated for their ease of wetting by placing a measured amount of the mixture (1/2 tsp) on the surface of a 6-oz, styrofoam cup filled 2/3 full of water. The time to completely wet the samples was recorded in min:sec with the results as follows:

______________________________________Compound Mean Time to Wet (3 replicates) Min:Sec______________________________________101 30:25168 7:15158 (standard) 79:12Control >180:00______________________________________

Compounds 101 and 168 of the present invention were clearly superior to the commercial standard, Compound 158, and furthermore gave more consistent results.

Following this test, a plant study using the same rates on commercial quantities of the growing media was conducted with the same results.

EXAMPLE 6

DEVELOPMENT OF A SUPERIOR WATER DISPERSIBLE, DRY FORMULATION FOR APPLYING THE COMPOUNDS OF THE PRESENT INVENTION

It is recognized that the use of corn cob grits, vermiculite, clay and other carriers is a well established procedure for the delivery of dry materials in agricultural and horticultural compositions of effective ingredients. To answer the question of an improved and novel method for delivering these materials as a dry formulation and to meet the needs for a more concentrated product studies were conducted to determine a more effective method for delivery of such materials. An example of the preferred chemistry was incorporated at various levels onto corncob grits, clay, vermiculite and amorphous/hydrous silica.

Examples of the preferred chemistry were incorporated on to selected carriers by placing an appropriate amount of the carrier and an appropriate amount of the desired compound in a cylindrical container which was then placed on a rolling apparatus to simulate the process of a ribbon blender for 30 minutes. Following the blending process the samples were removed and allowed to sit for 24 hours following which they were examined for absorption onto the carrier. A desirable formulation was one which had free flowing characteristics and would pass through a 20 cm diameter.times.20 cm tall funnel with a 2 cm opening without clogging or bridging.

The prepared formulations were then mixed with a sufficient quantity of peat moss to give the desired concentration of the active ingredient in the final mixture. These samples were then air-dried to 12-15% moisture contents. An equivalent amount of the carrier containing no active ingredient (0 ounces/cubic yard) was also added to act as a control and to demonstrate the effectiveness (or lack of activity) of the carrier and manipulated in the same fashion.

The following test was conducted to simulate conditions of placing the mix in a pot used for growing plants and to determine the number of waterings that a grower would have to perform to get good wetting characteristics in the growth media.

The prepared samples (200 cc) were placed in 6.times.13 cm tall cylinders to which a wire screen had been affixed on one end to hold the test preparation in place. The cylinders were tamped to insure even settling of the mix and then affixed upright to a ring stand by means of a clamp so that a 250 ml graduated beaker could be placed under the prepared cylinder. Next, 200 ml of water were added slowly to the top of each cylinder to measure the rate of absorption of water by the test mixture. The effluent was collected and measured in the beaker placed below the test cylinder. The resulting effluent was then reapplied until a total of 110 ml of water had been retained by the mix. (This value had been previously determined as the optimum level of water which 200 cc of peat under the conditions of the test could absorb). After each addition of water a representative sample tube was removed (and finally when 110 ml of water had been absorbed) and examined visually to determine the % Wet of the test material. The data are summarized in Table 6 as the number of passes required to obtain complete hydrature of the mix (110 ml absorbed and 100% wet).

TABLE 6______________________________________NUMBER OF PASSES REQUIRED TO OBTAIN COMPLETEHYDRATION OF PEAT AS MODIFIED BY VARIOUSSURFACTANT FORMULATIONS AND CARRIERS. FORMU- ACTIVE LATION INGREDIENT NUMBER RATE RATE OFFORMULATION (ON/YARD) (ON/YARD) PASSES______________________________________1. Peat Alone (Control) 0 0 8.52. Corn Cob grits alone 16 0 8.53. Vermiculite Alone 9 0 9.04. Silica Alone 8 0 8.05. Compound 101 Silica: 8 4 1.0 (50%)6. Compound 101 Silica 6 3 1.5 (50%)7 Compound 101 Silica 4 2 2.5 (50%)8 Compound 101 Corn 16 4 4.0 Cob Grits (15%)9. Compound 101 9 4 3.0 Vermiculite (40%)10. Compound 168 Silica 8 4 1.0 (50%)11. Compound 168 Silica 6 3 1.0 (50%)12. Compound 168 Silica 4 2 2.5 (50%)13. AquaGro Vermiculite) 16 8 3.5 (A commercial Standard)14. AquGro (Silica) 50% 16 8 2.5______________________________________

Neither corn cob grits nor the vermiculite had sufficient absorption capacity to hold the desired concentration (at least 50%) of the desired chemistry. The appigulite clay used in these studies had sufficient absorption capacity but did not perform well in efficacy tests.

The use of an amorphous silica based carrier for compounds of the present invention as well as other products in commerce was clearly superior in performance to the preexisting technology. The superiority of this carrier was surprising for this utility.

EXAMPLE 7

Finally, it is recognized that compounds and compositions of the present invention have certain unusual physical properties which make them difficult to use under practical conditions due to their incompatibility with aqueous ionic solutions such as fertilizers.

This problem may be overcome by adding an appropriate level from 1-49% but most desirably from 1-15% of a suitable co-solvent, emulsifying agent or dispersing agent such as a mono or di-alkyl phenol ethoxylate or similar materials which are known to the art.

The compounds and compositions of the present invention may be used alone or in combination with each other or with other compositions as described in Example 7 where they are the major component.

Claims

1. A composition for reducing hydrophobicity of soilless root media used in plant propagation which comprises an admixture of a liquid, water soluble surfactant composition selected from the group consisting of polyoxyalkylenes containing 10 to 20 mole percent of propylene oxide ethoxylated with from 1900 to 2000 molecular weight of Ethylene Oxide, 10 to 80 mole percent of ethylene oxide propoxylated with from 1700 to 3100 molecular weight of propylene oxide, alcohols having 4 to 14 carbon atoms which are propoxylated with from 4 to 12 moles of propylene oxide and ethoxylated with from 8 to 16 moles of ethylene oxide, and mixtures of the same and an amount of amorphous hydrous silica sufficient to form a free flowing mixture thereof, wherein admixing said free flowing mixture with a soiless root media selected from the group consisting of peat moss, bark, rockwool and mixtures of the same enhances the initial and rewettability thereof.

2. A method of delivering horticultural wetting agents to soilless root media used in plant propagation which comprises admixing a liquid, water soluble surfactant composition suitable for reducing hydrophobicity of soilless root media with an amount of amorphous hydrous silica sufficient to form a dry free flowing mixture thereof, and applying said free flowing mixture to said soilless root media, wherein said soiless root media is readily and substantially uniformly wettable by the initial and repeated application of water; wherein said liquid water soluble surfactant composition is selected from the group consisting of polyoxyalkylenes containing 10 to 20 mole percent of propylene oxide ethoxylated with from 1900 to 2000 molecular weight of Ethylene Oxide, 10 to 80 mole percent of ethylene oxide propoxylated with from 1700 to 3100 molecular weight of propylene oxide, alcohols having 4 to 14 carbon atoms which are propoxylated with from 4 to 12 moles of propylene oxide and ethoxylated with from 8 to 16 moles of ethylene oxide, and mixtures of the same, and wherein application of said free flowing mixture to said soilless root media enhances the initial wettability and rewettability thereof.