St. Gabriel Moss Killer

St. Gabriel Moss Killer is made from plant oils. It removes moss build-up on brick patios, sidewalks, etc

For best results, apply MOSS KILLER just prior to the time when fall rains begin or in early spring. Moss growth can occur in nearly any location where dampness persists. Such areas include decks, steps, patios and fences. Moisture is essential for moss growth, therefore, most moss growth appears during the fall; some occurs in the winter and spring. Very little moss forms in summertime. Controlling moss may add months or years of service to decks, fences, steps amd such areas, and can keep walkways and steps from becoming slippery and dangerous. Destroying existing moss is done most effectively during times when its growth is most rapid and when rain is not expected for several days.

St. Gabriel Moss Killer Concentrate:
Fill the spray tank 1/2 full with water and start agitation system if applicable. Add the desired amount of Moss Killer concentrate at a 3:1 mixing ratio. (Three parts water to one part Moss Killer)

Once in suspension, occasional agitation is recommended for best results.

BROADCAST APPLICATIONS: Spray Moss Killer to run-off using tank or backpack sprayers, typically 35-75 gallons of spray solution per acre.

BAND APPLICATIONS: Using trigger sprayers, cover moss, as needed, typically 25-50 gallons of spray solution per acre.

Moss and Algae Control in Lawns

Mosses are nonparasitic, primitive green plants that have fine, branched, threadlike stems with tiny leaves. They reproduce by means of wind-blown spores. Mosses typically form a thick, green mat on the soil surface. They produce their own food and do not kill grass plants but rather fill in the spaces in the lawn where grass is
not growing.

If mosses are present in your lawn, it indicates that conditions are not favorable for the growth of a healthy stand of grass but are favorable for the growth of mosses. The conditions that favor mosses over grass include: excessive shade, acidic soil, poor drainage, compacted soil, excessive irrigation, low soil fertility or some combination of these conditions.

While mosses can be removed mechanically or killed chemically, unless the underlying conditions are altered culturally to favor grass production, any solution that is attempted will be temporary. The conditions that are commonly associated with moss growth and their cultural controls are described below.

Algae are unicellular or multicellular, threadlike green plants that can form a dense coating or scum over the soil surface. This scum can form a tough black crust on the soil when it becomes dry, and will act as a barrier to water movement into the soil. Algal scum can be found on soils that are waterlogged and compacted, especially during sunny, warm and humid conditions.

Dense Shade: In general, mosses can tolerate more shade than grasses can. If the mosses present in your yard are limited to shady areas, your options include:

• Planting a more shade-tolerant grass (keeping in mind that an area receiving less than four hours of full sunlight per day is too shady for grasses).
• Mowing grasses in a shady area at the top of their recommended mowing height range to encourage deep rooting and provide maximum leaf surface area to intercept the limited sunlight in order to manufacture food. For more information on recommended mowing practices, you can request HGIC 1205, Mowing Lawns.
• Planting a shade-tolerant groundcover rather than a grass.
• Covering the area with mulch (pine straw,
  bark, etc.).
• Pruning some limbs, especially lower ones, from shrubs and trees.
• Removing some of the trees and shrubs.
• Enjoying the moss as a low-maintenance groundcover that requires little, if any, watering, no fertilizer or mowing, and stays green all year so long as it does not receive much traffic.

Acidic Soil: Mosses prefer acidic soil. With the exception of centipedegrass, most lawn grasses prefer a pH of 5.8 to 6.5. Centipede prefers a pH between 5.5 and 6.0. If the pH of your soil is lower than that recommended for your grass, you can raise the pH by adding agricultural or dolomitic lime. The higher pH will not kill the mosses, but will favor the growth of the grass.

To determine the pH of the soil, take a soil sample to your county Cooperative Extension office. For more information on how to take soil samples, you can request HGIC 1652, Soil Testing.

Poor Drainage: While mosses will grow in well-drained soil, they grow better in wet soil than do grasses. Excessively wet soil is one of the more difficult conditions to alter. Possible solutions include:

• Altering the contour of or trenching the area to drain water.
• Altering the elevation of the area (if the wet area is small) by adding sand or soil.
• Installing French or tile drains (if the wet area is more extensive).
• Digging a sump (a pit that receives drainage) in the low spots, backfilling with sand.

Compacted Soil: Soil compaction prevents a lawn from growing vigorously. It also often prevents internal drainage, providing wet conditions favorable to mosses. When the top 4 inches of soil are compacted, movement of air, water and nutrients to the grass roots is adversely affected. In addition, it is difficult for grass roots to penetrate compacted soil. These factors place stress on the grass and decrease its ability to recuperate
from damage.

To determine if your soil is compacted, use a soil probe to take a few plugs of soil. This can be done with a piece of ½- to ¾-inch diameter metal pipe. The probe should easily penetrate the top 4 to 6 inches of soil. Use a smaller diameter rod to push the plug of soil out of the pipe. Examine the plugs for the fine white roots. Grasses growing in compacted soil tend to be shallow-rooted. The roots may not extend further than 1 inch into the soil when they should extend 6 or more inches.

A process known as core aeration or aerification will help alleviate soil compaction and improve growing conditions for the grass. This process involves physically removing cores of soil from the lawn, and for some lawns should be repeated annually. Aerification is not expensive and can be accomplished with a spading fork, a manual sod-coring tool or a power-driven core aerator. For more information about aerating lawns, you can request HGIC 1200, Aerating Lawns.

Excessive Irrigation: Automatic watering on a regular schedule tends to promote problems with excessive moisture, especially in shady or poorly draining areas. As both of these areas are already prone to moss problems, excess moisture just adds to the problem.

It is best to water your lawn only when it is needed. When you see signs of moisture stress such as grass with a dull, bluish-gray cast, footprinting (the presence of footprints when you walk on the lawn late in the day), and wilting or folding grass leaves, you should irrigate with ²/3- to ¾-inch of water. This amount will moisten the soil to a depth of 4 to 6 inches. The key to proper watering of the lawn is to water infrequently but deeply. For more information on watering your lawn, you can request HGIC 1207, Watering Lawns.

Low Soil Fertility: If required nutrients are limited in your soil, lawn growth and quality may be limited, also. Those nutrients that are essential for growth can be added to the soil through fertilizer applications. In addition to providing the pH of your soil, a typical soil sample analysis will determine the levels of phosphorus, potassium, calcium, magnesium, zinc and manganese in your soil. The nitrogen requirements of the turfgrass cannot be reliably evaluated by a soil test. As a result, the soil test will not contain a nitrogen recommendation. For recommended nitrogen applications for your lawn, you can request HGIC 1201, Fertilizing Lawns.

Once you have altered as many of the underlying conditions as possible, you can remove the moss by hand raking or by using a chemicals such as ferrous sulfate monohydrate (Scotts Moss Control or Ortho Moss-B-Gon) or potassium salts of fatty acids (Safer Moss and Algae Killer) to kill it (read and follow label directions and precautions). Another control option is the use of copper sulfate or ferrous (iron) sulfate mixed at the rate of 5 ounces in 4 gallons of water sprayed over 1000 square feet. After the moss has been killed, apply 5 to 10 pounds of ground limestone to inactivate the copper sulfate prior to reseeding with grass, which may be toxic to grass seedlings. Other options include ground limestone (75 to 100 pounds per 1000 square feet) or hydrated lime (2 to 3 pounds per 1000 square feet in 3 gallons of water), or diluted bleach (2 to 4 ounces per gallon of water), or dishwashing detergent (2 to 4 ounces per gallon of water). Note: one ounce equals two tablespoons.

These materials kill the moss because they act as desiccants (drying agents), should be applied by over the moss-infested areas during winter through early spring (December through April) when moss is actively growing and temperatures are cool. Apply when the lawn soil is moist. To be effective, they need a 24-hour rain-free period after application. As the moss starts to die, it will turn orange-brown or golden brown. Once the moss is dead, remove it by raking.

Algae can be controlled by using potassium salts of fatty acids (Safer Moss and Algae Killer) to kill it (read and follow label directions and precautions) or copper sulfate mixed at the rate of 2 to 3 ounces (about one teaspoon) in 8 gallons of water sprayed over 1000 square feet. After the algae has been killed, apply 5 to 10 pounds of ground limestone to inactivate the copper sulfate prior to reseeding with grass, which may be toxic to grass seedlings. The dead algal crust may have to be removed by raking.

If large bare areas remain after moss or algae removal that require renovation, follow the recommendations provided in HGIC1204, Lawn Renovation.

Moss in a lawn is an indication that the turf is not growing well. It is important to consider that moss does not kill the grass; it simply creates unfavorable growing conditions such as shade, poor drainage, poor fertility or compacted soil.  These conditions, not the moss, ultimately cause the grass to die out.  If you want to eliminate moss from a lawn, focus on imporving conditions for growing grass, and don't worry about the moss -- it will disappear on its own as the grass gains vigor.

Herbicides and chemical control have only short term effects on moss. If herbicide use is not accompanied by proper environmental and physical controls, then the initial effect will be bare dirt or mud. Mosses will eventually return because the lawn deficiency, which led to the moss invasion, still exists. When herbicides alone are used, the symptoms, not the cause, of a weedy lawn are being treated. Furthermore, many of the common herbicides, such as glyphosate, are ineffective against mosses, at least in some conditions (Woodfill 1999; Roberts and Ziegenhagen 1999). Therefore, if you perceive of the moss in your lawn as a problem, improve conditions for growing grass, rather than using herbicides.

Photo at right: Lawn area with poor vigor of grasses and mosses in the open spaces.

Glyphosate

One of the most common herbicides in use today is glyphosate (for example in Round-Up). This herbicide is often not effective against mosses (Woodfill 1999; Roberts and Ziegenhagen 1999; Newmaster et al. 1999) but does kill mosses in other cases (Newmaster et al. 1999). This chemical is absorbed through the leaves, becomes tightly bound to the soil, and is degraded by microbes. The failure of many common herbicides against mosses can be seen dramatically in some christmas tree plantations and other perennial crops where competing higher plants have been killed by herbicides, leaving a green carpet of mosses and other bryophytes. The situations in which glyphosate does or does not kill mosses remain unclear.

Ferrous sulfate, Ammonium sulfate and copper sulfate

Iron sets back mosses while having little effect on the grass.  However, iron will not always kill the moss. It may "burn" the moss severely and render the plant very weak. If the moss is to be eliminated, it must be removed and grass seed sown into its place for a thick turf. Even so, if the conditions that favor the moss are not changed, the moss will recover over time, and it will not look like an application was ever applied.

Moss can be controlled with products containing Iron Sulfate, and Ferrous Ammonium Sulfate. A good mixture is approximately 3 ounces of Iron Sulfate in 5 gallons of water.  A five-gallon mixture should be sprayed over a 1000 sq. ft. area.  Products such as Moss-Out  (ferrous ammonium sulfate) can be used to control moss.  Note that it is best to keep the Moss-Out product away from sidewalks and driveway concrete, because it will stain the concrete. 

Moss can also be controlled by spraying with copper sulfate at a rate of 2 to 5 ounces in 4 gallons of water. The 4 gallons will be sufficient to cover 1000 square feet. However, the material could stain your hands and clothing, and may be caustic to metal containers.  None of these materials pose serious threats to the environment; in fact Iron and Sulfur are essential elements for successful plant growth.

Lime

Lime is a good product to control acidic conditions in your lawn. Over time, the acidic conditions can become detrimental to grass health by binding up the availability of important nutrients. By liming the turf, especially with a calcium-based lime, one can neutralize the acidity, building a better lawn and a stronger competitor for weeds and moss. The ideal soil pH for most lawns is 'neutral', about 6.5 to 7. A pH below 6 is considered 'acidic' and over 7 is 'alkaline'. Acid soil will often be associated with poor fertility, and may encourage moss growth in bare areas.  Limestone is the common remedy used to 'neutralize' acid soils. If test of your lawn show pH 4 or 5, then applying limestone twice each growing season, in addition to regular fertilizer applications, should significantly improve the pH level. Do not add lime to control a moss problem unless a soil test indicates a need for lime.

Fertilizer

Poor soil fertility can be a cause for lawn moss growth.  If moss grows in areas of your lawn that appear dry and sunny, then the appearance of moss is probably caused by poor soil fertility.   To see if low soil fertility is contributing to a moss problem, take a representative soil sample from the areas where moss usually grows and have it tested. If tests show deficiencies in certain nutrients, addition of those nutrients could alleviate the problem. Only apply fertilizers if it is needed. Over fertilization can cause other problems, including pest infestations and possibly groundwater contamination.  At the same time your moss problem remains unaffected if low soil fertility was not   the cause to begin with.

Fertilization with a high nitrogen fertilizer can have a significant effec t on moss reduction, and supports the growth of healthy turf. Monthly applications of iron and potassium, in combination with nitrogen, are also helpful.  Specific moss control fertilizers are available that contain nitrogen, potassium and iron. These are most effective in a four-application per year program, with applications in early spring, late spring, mid-summer, and early fall. As with all fertilizers, carefully read and follow the directions on the product.

Photo at right: Area chemically treated for moss control.