Recuperative Capacity - The ability of turfgrasses to recover from damage. It is an important consideration when determining grass selection for high use areas such as sports fields.
Reel Mower - A mower that cuts grass by means of a rotating reel of blades passing over a fixed blade (called a bedknife) attached to the frame. Very uniform, clean cuts can be made with this type of mower.
Rejuvenation - Stimulation of grass growth usually through the removal of thatch and may include the process of aerification to improve compacted soil conditions.
Renovate - To restore to a previous condition, revive.
Renovation, Turf: - Improving a stand of turf through replanting into an existing lawn area. May also include practices associated with rejuvenation.
Rhizome - An elongated underground stem with scale-like leaves and adventitious roots originating from the nodes (bud containing areas along a stem).
Rhizomatous - A spreading growth habit resulting from the production and elongation of rhizomes.
Root - The fibrous, underground part of a plant associated with mineral and water absorption.
Root Zone - That portion of the soil column occupied by plant roots.
Rotary Mower - A mower that cuts turf by a high-speed, rotating metal blade positioned parallel to, and at a desired height above the turf surface.
Rotary Spreader - A spreader, most often used in the application of fertilizer, that distributes the material in an arc, several feet wide, by means of a rotating disc below the fertilizer hopper. It is able to cover large areas quickly, but distribution may not be precise enough for some applications.
Rototilling - The process of working (tilling) the soil utilizing a machine known as a rototiller. The machine utilizes a series of vertically rotating tines (blades) mounted on either the front or rear of the machine. It is capable of penetrating 6 to 8 inches into the soil.
Scalping - An undesirable mowing practice that removes an excessive amount of green leaves and shoots at any one mowing. It can seriously weaken or even kill the turfgrass.
Sediment - Any material settling to the bottom of a liquid. Its usage in this section refers to any material carried in runoff water that, upon reaching a body of water, settles to the bottom.
Sedimentation - The process of depositing sediment; generally referring to the depositing of sediment in a water body such as a lake or river. Also see sediment.
Seed - A ripened ovule containing an embryo capable of producing a new plant.
Seed Count - The actual number of seeds of a particular species or variety contained in a seed blend or mixture.
Seed Weight - The actual weight of seeds from a particular species or variety contained in seed blend or mixture. Expressed as a percent of the total weight.
Seeding - The process of distributing seed over the soil surface, either mechanically or by hand, in an attempt to establish a new lawn or renovate an existing lawn.
Selective - The term usually applied to an herbicide that has the ability to only destroy one type of plant while not affecting others. For example, a postemergence, broadleaf herbicide will kill broadleaf plants (such as dandelions) in the lawn without affecting the grass plants.
Shade - An area of reduced light quantity (and often quality) resulting from the partial or complete obstruction of direct sunlight.
Sheath - The tube shaped, basal section of the grass leaf enclosing the stem.
Shoot - Above ground, vertically oriented growth giving rise to both leafy growth and flowering stems (culms).
Shoot Density - The number of shoots contained in a specified area of lawn.
Short-Day Response - Usually applied to plants where flowering is hastened by daily exposure to light shorter than a specified number of hours.
Slit-Seeding - The use of a machine known as a slit-seeder to seed a new lawn area or overseed an existing area. Slit-seeders utilize a series of vertically rotating discs to cut small grooves into the soil while depositing seed into the grooves just behind the discs. It is an excellent means of seeding and helps insure the seed-to-soil contact necessary for successful establishment.
Sloughing-Off - The periodic shedding of plant parts. As used here, it refers to the periodic shedding of turfgrass roots as either part of the natural growth cycle, or as a result of environmental stresses.
Slow-Release Nitrogen Source - Nitrogen from these sources becomes available as the product is broken down by soil microbes and/or chemical action. Plant responds with a slightly slower rate of green-up and growth. Usually this is a desirable characteristic.
Sod - squares or strips (rolls) of turfgrass cut from a production field and usually with a thin layer of soil still attached that is used for vegetatively installing a turfgrass area.
Sod Cutter - A machine or hand tool that is designed to cut the grass plus a thin layer of soil from the ground. The length and thickness of the cut sod can be varied.
Sodding - Installing a turfgrass area utilizing sod.
Soil - The earth's thin upper layer capable of supporting plant growth. It is characterized by such things as texture, structure, color, and fertility which distinguishes it from material like gravel, sand or bedrock that also cover a portion of the earth's surface.
Soil Structure - The combining of microscopic soil particles through the action of soil microbes into larger units commonly known as soil granules, crumbs or aggregates. Loose, crumbly soil structure is a must to sustain health plant growth.
Soil Test - A scientific analysis of a soil sample that determines its pH, texture, organic matter content and various degrees of chemical composition. They are used to assess a soil's suitability for particular uses and any necessary modifications to prepare it for the intended use.
Soluble (Fertilizer) - Fertilizers that are made up of easily dissolved components in water which are immediately available for plant use; they can result in lawn "burning" more easily that slow-release fertilizers.
Species - A basic identification unit used in biology to describe a single distinct kind of plant or animal that has certain distinguishing characteristics separating it from all others.
Spot Treatment - Generally refers to the application of a pesticide to a limited or small area. In the case of herbicides, it may also be applied to the treating of individual plants.
Spreader - A piece of equipment used for seeding and fertilizing. It may be machine driven, pushed by hand or hand-held.
Spreading - The application of grass seed or fertilizer to soil or existing lawns usually by some form of a spreader.
Stem - The horizontal or vertical axis of a plant supporting leaves, buds and flowers.
Stolon - An elongated stem growing along the ground surface and giving rise to leaves and adventitious roots at the nodes (bud containing areas along a stem).
Stoloniferous - A spreading growth habit resulting from the production and elongation of stolons.
Storm Sewer System - A system of ground level inlets (usually covered with some type of steel grate) designed to intercept storm water runoff from the adjacent land areas and channel it below ground to a system of interconnected pipes that eventually empty into wetlands, lakes, rivers, streams or other designated storm water holding areas.
Storm Water Runoff - Rain water that cannot soak into soil and runs over surfaces such as streets, driveways and rooftops. Storm water runoff picks up pollutants as it moves.
Stress (Plant) - Usually applied to environmental factors restricting normal or healthy plant growth. Some of these factors are heat, drought, compacted soils, waterlogging and cold.
Summer Dormancy - All water naturally opens to the atmosphere (rivers, lakes, reservoirs, ponds, streams, seas, estuaries) and all springs, wells, or other collectors are directly influenced by surface water. Growth stoppage and subsequent death of leaf tissue of certain cool-season grass species due to heat and/or moisture stress. Except in extreme conditions, the crown remains alive and begins regrowth when favorable growing conditions return.
Sustainable (Lawn) - A lawn area requiring few outside inputs (e.g., water, fertilizer) to maintain healthy grass while having a positive impact on the environment (e.g., preventing soil erosion).
Symptom - An abnormal condition in the form or function of a plant or part of a plant that helps identify the disorder.
Synthetic Organic Nitrogen Fertilizer - Generally refers to fertilizers formed when urea, a quick-release N fertilizer source, is further processed or combined with other materials to give it a slow-release rate characteristic.
Syringe - Usually a term referring to the application of small amounts of water to turf to help dissipate heat energy from the plants by evaporating water from the leaf surface. Often done during the hot portions of the day.