Landscape Specification RFI SOW .pdf

SOW LANDSCAPE MAINTENANCE SPECIFICATIONS

SOW

February 20, 2024

I. GENERAL

A. DESCRIPTION OF WORK

Furnish all labor, materials, tools, equipment, and services necessary for and reasonably incidental to complete landscape maintenance services as specified including, but not limited to the following:

1. Installation and maintenance of landscape materials, surfaces, bio retention areas, green roofs, ponds, wetlands, and irrigation systems.

2. Purchase, installation and/or transplanting of landscape materials and surfaces.

3. Removal and proper disposal of landscape waste and materials.

4. Subcontracting: Pest control, tree work, invasive species management, irrigation design, installation and maintenance, planting design diagrams. This work may be subcontracted.

B. RELATED DOCUMENTS

General provisions of the contract to be included

C. SCHEDULING OF WORK

Service shall be performed according to the provided specifications, It is the responsibility of the Contractor to prepare more precise weekly work schedules for approval by the COR and to contact the GSA Horticulturist on a regular basis to coordinate specific work. It is the responsibility of the contractor to notify the GSA Horticulturist of any schedule changes. A mutually agreeable manner of daily communication will be determined after award.

1. Telephone Listing: The contractor shall provide an up-to-date list of cell telephone and email addresses.

D. WORK HOURS

Most of the work shall be performed within the normal five (5) day work week observed by occupants of the site(s), holidays excluded. The

Contractor shall respond within an hour to emergency, hazardous, or high priority items, such as a fallen tree, as requested by the COR.

Any work performed outside of normal working hours shall be done at no additional cost and shall commence only after prior approval for such work has been obtained from the COR. Some duties may have to be performed on weekends.

E. WORK CONDITONS

1. Contractor Responsibility: The contractor shall assume full responsibility and liability for compliance with all applicable regulations, including Occupational Safety and Health Administration (OSHA) and

GSA Health and Safety Specifications, pertaining to the health and safety of personnel during the execution of work, and shall hold the Government harmless for any action on the part of its employees or subcontractors that results in illness or death. The contractor is required to have utilities marked before digging.

2. Interference Resulting from Work: Conduct operations to ensure minimum interference with roads, streets, walks, and other adjacent occupied or used facilities. Do not close or obstruct streets, walks or other occupied or used facilities without permission from the COR or authorities having jurisdiction.

3. Storage of Materials and Equipment: The Contractor shall not store equipment nor stockpile material on-site without prior approval from the

COR.

4. Ownership and Purchase of Materials: The Contractor will purchase and have delivered plant material to be installed as part of this contract, as requested by the COR. Plant material is subject to acceptance by the COR, must be high quality, and the correct selection that was ordered. The Contractor shall be responsible for its viability, proper transportation and/or installation at the designated location. Plant material once installed, becomes the property of the Government.

Reimbursement by the Government will be made through GSA Finance or government purchase card.

The Contractor, at the discretion of the COR, will be responsible for:

Purchasing and installing with like species/cultivar and size, or otherwise approved by the COR, any plant material that dies or has become unsightly due to the contractor’s negligence at no additional cost to the Government.

Upon request by the COR, the Contractor will design and install irrigation systems. All material purchased and installed as part of this system, is the property of the Government. For the first year, the

Contractor will fully guarantee, service, and repair the system. After the first year, the Contractor will be responsible for maintaining the system, spring-start up and winterization, minor adjustments and monitoring.

Repairs will be paid through Additional Services.

5. Protection: All necessary precautions, including the use of appropriate warning signs and barricades, shall be taken to prevent personal injury, damage to property (including existing landscape materials, surfaces, and structures), and/or damage to the environment when conducting operations.

a) Replace or restore damaged landscape materials, landscape surfaces, or structures caused by normal operations and/or because of the Contractor’s negligence as acceptable to the

Government or parties having jurisdiction, at no additional cost.

6. Work Completion: Work shall not be considered completed until the

Contractor has removed from the premises all trash, debris, litter, etc., which accumulates in the performance of work. Containers for handling this material shall be furnished by the Contractor.

7. Planting Installation: Installation shall consist of seasonal, replacement, and new designs. Planting installations will be charged as an additional service according to the pre-negotiated price.

a) Maintenance Responsibility: At the completion of any installation work performed under another contract, the Contractor shall inspect the site with the COR to accept the work. The

Contractor and the COR shall come to an agreement on any changes and/or corrections needed.

8. Composting: To help reduce the amount of material being disposed of in landfills, the Contractor is required to compost all landscape waste generated by the Contractor’s operations. The contractor must compost the material at the Contractor’s own facility or propose an alternate location to GSA.

9. Minimization of Air Pollution: The use of gas-powered leaf blowers will be incrementally phased out according to the schedule from the contract Base Year to Option Year 2.

a) Reduced Ozone Emissions: On days when warnings are issued that the region may exceed the Federal Health Standard for ozone, minimize the use of all gasoline powered equipment.

b) Proper Equipment Fueling: The Contractor shall fully instruct all employees on the proper and careful way to fuel equipment.

F. QUALITY ASSURANCE: All work shall conform to the most stringent applicable Federal, State, County or local jurisdiction regulations where the site is located, in addition to the requirements listed in this Section.

1. Contractor Self Inspection: The Contractor shall establish a complete Quality Control Program to ensure compliance with the contract work requirements.

2. Service Proposals: The Contractor may suggest procedural or methodological; executionary; modifications to the COR while maintaining the established standards.

G. INSPECTION OF WORK: Although the performance and management of all work requirements is the responsibility of the Contractor, the premises will be inspected routinely by Government personnel.

II. EXECUTION OF WORK: The contractor shall perform, at least at the minimum standard indicated, the following work. All dates, quantities and formulations are approximations. Specific dates, quantities and formulations will be in accordance with the standards established in the Contractor’s monthly schedule in allowance of weather, ceremonial events, and other considerations.

A. PRUNING: The on-site supervisors performing tree pruning services shall be certified arborists, by the International Society of Arboriculture, and shall abide by the standards established by the National Arborist Association. Shrub pruning shall be supervised on site by the Contractor’s Horticulturist or Contractor’s

Arborist. Workers shall be under strict supervision, be experienced in arboriculture, and abide by industry standards as well as those established by the National Arborist Association.

1. Tree: Pruning shall include, but not be limited to, removal throughout the year, at no additional cost, of branches that limit the headroom of pedestrians and vehicles, sucker growth, water sprouts and low hanging branches. All other tree pruning, and removal shall be done as an additional service off the pre–negotiated price list.

2. Shrubs: Plants will be informally pruned, unless otherwise directed by a GSA Horticulturist. Because of space limitations and growth habit, some shrubs may require more than one pruning a year. Throughout the year, any damaged or unhealthy branches shall be removed in a timely fashion. Specific pruning requirements may be directed by a GSA

Horticulturist.

3. Scheduling: General pruning shall be done during the dormant season, January and February. Other pruning shall be performed as noted in the provided schedule.

B. SOIL TESTS: Soil tests shall be done as directed by the COR and shall be paid for through additional services. Soil tests shall be conducted by a government laboratory or recognized commercial laboratory. Certified copies of the soil test shall be submitted to the COR, by the Contractor.

C. MULCHING: Mulch shall be commercial grade double shredded hardwood bark, leaf compost, pine fines or pine straw as directed by the GSA

Horticulturist. Samples may be requested by the COR prior to application. It shall be free of sticks, stones, clods or other foreign material. All areas to be mulched shall be raked, debris removed, edge reestablished, and any excess mulch buildup worked into existing soil or removed, at the discretion of the COR, prior to mulch application. All ornamentals, including borders and openings within ground cover beds shall be mulched. Mulch shall be applied evenly at a depth of two (2) inches or as directed by the GSA Horticulturists

1. Scheduling: Application shall be between January 1 and March 30.

Mulch must be applied one time per year per the contract. Additional mulch applications may be requested by the COR and shall be covered under the additional services.

D. FERTILIZING: Fertilizing shall be performed in the landscape as needed and shall be determined by a soil test conducted by the Contractor at the request of the GSA Horticulturist. Fertilizer type, application rates must comply with specific nutrient load regulations in the State of Maryland, Virginia and the District of Columbia as specified by the appropriate authority in each respective jurisdiction.

1. Scheduling: If needed, fertilizer application for trees, shrubs, ground cover and herbaceous perennials shall be done in early spring or fall at the direction of the GSA Horticulturist.

E. CORE CULTIVATION: Coring shall be performed once a year, in the fall between September 15 and October 15, prior to over seeding of turf. In the areas with underground irrigation systems, irrigation heads must be marked in advance.

F. PEST CONTROL: The Contractor shall be responsible for adhering to an

Integrated Pest management Program (IPM) as directed by the COR. The IPM program must include the following:

1. Application Technique: Any chemical used to control pests is a pesticide. Pests include insects, plant diseases, fungi, weeds, nematodes, snails, and slugs; therefore, insecticides must be used to obtain adequate control, the Contractor shall employ the least hazardous material, most precise application technique, and minimum quantity of pesticide necessary to achieve total coverage of targeted plant material. Labels and

Material Safety Data Sheets for all pesticides used shall be provided to the

2. Application Responsibility:

a) Certification: The Contractor and all personnel performing on site pest and disease control service shall be certified as

Commercial Pesticide Applicators in the category of Exterior

Ornamentals and Turf. Uncertified individuals working under the supervision of a Certified Applicator will not be permitted to provide service under this contract.

b) Application and Handling: Pesticide application shall be according to need and not by schedule. The contractor shall be responsible for application of pesticides according to the label. All pesticides used by the Contractor must be registered with the

Environmental Protection Agency (EPA), state, and/or local jurisdiction. Transport, handling and use of all pesticides shall be in strict accordance with the manufacturer’s label, instructions and applicable Federal, state and local laws and regulations. No pesticides shall be applied in and immediately adjacent to outdoor playground areas. Application hours will be directed by the COR and may have to take place outside of normal working hours.

3. Insect and Disease Control: As determined through site inspections, only those specific ornamentals and lawn areas that have pest or disease problems shall be treated as directed by the COR.

a) Ornamentals: Ornamentals shall be treated for disease and insects as needed as directed by the COR.

b) Turf: Turf applications shall be applied outside normal working hours, unless approved by the COR.

4. Weed Control: Weed control, except for pre-emergent applications, shall be performed when weeds are actively growing, and includes the killing and complete removal for all weeds from the following areas: No products, containing 2, 4-D or Imidacloprid shall be used on this contract with no exceptions. All pesticides used must be approved by the COR.

a) Ornamentals: Trees, shrubs groundcover, and herbaceous perennials shall be weeded as necessary, to maintain a weed free condition. Most of this work must be accomplished by manual weeding: pre-emergent herbicides may only be used with the prior approval by the COR. If herbicides are utilized, care must be taken not to damage the plant material.

b) Turf: Lawn areas shall be treated as directed by the COR.

Turf application shall be applied after normal working hours, unless approved by the COR.

c) Non-Planted Areas: Parking lots, sidewalks, gravel areas, etc. shall be maintained in a weed free condition.

d) Fences: Interior fences shall be treated as necessary to maintain a six (6) inch bare strip on both sides. Perimeter security fences, except those that lie within or adjacent to delineated wetlands, shall also be maintained with an eight (8) foot wide access clear of brush and trees where wooded areas abut the fence. Fences within or adjacent to delineated wetlands shall be maintained with a one (1) foot wide access free of vine and brush growth and leaning or fallen trees or limbs.

e) Green Roofs: Shall be serviced to remove weed growth as needed, at a minimum of three (3) times per year as scheduled by the COR. Contractor must provide inspection reports for all service visits annually. Green roofs containing herbaceous perennials and ornamental grasses must be serviced to remove previous year’s growth in late winter prior to new growth emerging. All plant debris generated from maintenance activities must be removed from roof tops.

G. GRASS CUTTING: Mulching mowers are required for use on this contract.

Grass clippings are not to be collected or removed from lawn areas. Grass cutting shall be scheduled so that it does not interfere with outdoor activities, vehicle parking etc. All gasoline-powered, motorized equipment shall conform to requirements and exhibit Minimization of Air Pollution. Turf shall be cut at a height of no less than three (3) inches or as directed by the COR. Accumulated clippings on the turf shall be dispersed to provide a neat clean appearance upon completion.

1. Rough Cut: Perimeter and low visibility areas may be cut with reduced frequency as directed by the COR.

2. Edging: Edging around curbs, walks, etc. shall be done with a string trimmer each time the grass is cut. A well-defined line must be established and maintained.

3. Trimming: Trimming around monuments, flagpoles, walls, signs, etc., shall be done each time the grass is cut. Trimming height is to be the same height at which the grass was cut.

4. Equipment: Mulching mowers are required for this contract. Non gas-powered mowers may be used as approved by the COR.

5. Reduced Emission: On days when ozone warnings are issued that the region may exceed the Federal health standard for ozone, minimize the use of all gasoline powered equipment.

H. HERBACEOUS PLANT CUTBACKS:

1. Herbaceous Plants: Herbaceous perennials, ornamental grasses, and groundcover plants shall be cut back seasonally. Plants shall be cut down in fall or winter as directed by the COR. In all areas work must take place prior to spring bulbs emerging.

2. Bulbs: In those areas where bulbs have been planted among other plants, the foliage of the bulbs shall be removed once the foliage has fully matured and turned brown.

I. EDGING: Ornamental beds shall have a well-defined edge established and maintained.

J. WATERING The Contractor shall be required to water ornamentals and turf as needed. Watering entails the use of all available hose bibs, irrigation systems, and/or any other means necessary, including use of a water truck, to water the entire premises. Plant material should be maintained to always appear healthy and robust.

1. Water Source: The Contractor may connect to existing hose bibs, water lines, or other connections which are provided for the purpose of watering, otherwise water shall be provided by the Contractor. The contractor shall provide the hose, sprinklers, water bags for newly planted trees and any other equipment needed to properly apply the correct amount of moisture. The Contractor shall use the irrigation system, if existing.

2. Underground Irrigation Systems: In areas where there is automatic underground irrigation, the Contractor shall be responsible for operating, and maintaining the system, including minor adjustments, monitoring, and winterization. Any repairs or modification shall be paid for by additional services.

a) Irrigation systems shall be activated and inspected in the month of April, by the Certified Irrigation Contractor or Specialist as part of the Contractor’s Quality Control Program and assessed for coverage, need for spray head or any other adjustments, troubleshooting, adequate water output and general functioning. A report shall be submitted to the COR within 5 days of the inspection as part of the QC report and shall include findings, and action taken, or action needed. Contractor shall implement Irrigation

Association’s Irrigation Best Management Practices.

K. BED PREPARATION and PLANT INSTALLATION: Preparation shall be performed at each installation of plants and as requested by the COR, as follows:

1. Soil Preparation: Clear soil of all surface growth and till soil to achieve a smooth texture, apply soil amendments as directed by the COR.

Compost/leaf mold shall be evenly spread on soil surface. Sample shall be submitted to COR prior to use. A lab analysis of materials may be requested by the COR.

2. Finished Grade: Planting bed shall be neat in appearance with a well-defined edge.

3. Material Handling: All plant material shall be specified by the COR, purchased by the Contractor, and reimbursed through GSA Finance.

4. Planting: Plant in holes large enough to allow for spreading of roots and at depths recommended for each type of plant. Space of plants will be directed and approved by the COR. The COR will provide the contractor with a drawing, plan, or verbal description of how plants are to be planted unless the Contractor has been directed to provide this by the COR.

5. Mulch: Mulch shall be applied at time of plant installation.

6. Watering: The Contractor shall be responsible for watering the plants immediately following planting and throughout the critical establishment period. Care shall be taken not to disturb plants, or to induce excessive runoff.

L. BED AND PLANTER MAINTENANCE: The contractor shall provide a maintenance program implemented by personnel who possess knowledge of the cultural requirements of all plant material under this contract. Plant material must be kept in a healthy and robust condition with a good appearance.

1. Watering: The Contractor shall water plants as required, to maintain soil moisture as necessary and to always maintain a healthy appearance.

Contractor shall be required to apply water when visual appearance indicates or as directed by the COR.

2. Weeding and Cultivation: The Contractor shall always keep landscape beds and planters free of weeds. During the growing season, after weeding, the Contractor shall cultivate and restore bed edges where needed to always maintain a uniform appearance.

3. Trimming and Pinching: Spent blooms, dead foliage and unusual sprouts shall be removed regularly.

4. Fertilization: Plants shall be fertilized as directed by the COR.

5. Pest and Disease Control: If pests or disease become evident and treatment is necessary, appropriate pest control shall be provided by the contractor at the request of the GSA COR.

6. Security Planters: All security planters require watering and weeding to keep plants healthy, and planters always weed free.

Replacement plants for planters will be done as an additional service.

M. TURF RENOVATION: If required, turf shall be renovated as follows:

1. Locate and mark all underground irrigation.

2. Cut grass to a height of three (3) inches.

3. Perform the following:

a) Core aerate.

b) Overseed at the rate of four (4) pounds of seed per one thousand (1000) square feet of area. Apply seed uniformly.

c) Immediately after seeding, the entire area shall be watered and then kept moist until even germination is achieved.

4. Scheduling: Turf shall be renovated between September 15 and

October 30.

N. LEAF REMOVAL The Contractor shall remove leaves, as necessary throughout the year, to maintain a neat and clean appearance. The Contractor’s performance of this work shall be done in a careful manner that maintains mulch in a neat and clean appearance. Mulching of leaves with mulching mowers is the preferred means of leaf removal.

O. SPECIAL LANDSCAPE FEATURES

1. Bio-Retention Cells (Rain Gardens): Maintenance shall be appropriate for plant material. Ponding should not be occurring for longer than 48 hours. Contractor shall visually inspect monthly throughout the year and report if drainage is not occurring as intended. Any accumulated sediment will be removed throughout the year as needed. Overflow drains shall be kept clear of debris.

2. Green Roofs: The Contractor shall be responsible for the green roof maintenance. Contractor shall inspect the roofs regularly throughout the growing season to ensure roofs are kept weed free and free of all non-desirable plant species, including tree seedlings. Roofs shall be weeded at a minimum of two (2) times per year during the growing season as directed by the GSA COR. Herbaceous plants and ornamental grasses must be cut down and removed annually in late winter.

a) The landscape contractor will ensure their workers are in compliance with OSHA’s Duty to Have Fall Protection (29CFR

1926.501) when service/maintenance work is required in any areas with an unprotected side of edge which is 6 feet or more above a lower level, shall be protected from falling using guardrail systems, safety net systems, or personal fall arrest systems. In addition, on a roof with slopes of 4% or less see (29 CFR 1923.501-502) also allows the use of warning line systems with safety monitors.

P. ADDITIONAL SERVICES: As requested by the COR, the contractor shall provide the following services:

1. Furnishing Topsoil: Topsoil shall be provided for planting, topdressing, leveling and earth working purposes. Topsoil shall be fertile, friable, natural surface soil obtained from well drained areas, representative of productive soils in the vicinity, and suitable for growth of grass and other plants. It shall be free of subsoil material, sticks, stones, weeds and debris and other material harmful or toxic to growth. A sample, with analysis, shall be submitted to the COR, for approval as needed.

2. Sodding: Sod shall be certified, healthy and in vigorous condition upon installation. Sod shall be laid to form a solid mass with tightly fitted joints. Sod laid on extreme slopes shall be installed at right angles and secured with sod pins. Sod shall be thoroughly watered after installation and kept moist until established. If necessary, the Contractor shall provide and install protective fencing as an additional service.

3. Seeding: Bare ground shall be cleared of all debris and unwanted vegetation and raked smooth. Seed at the rate of six (6) pounds of seed per one thousand (1000) square feet of area. If necessary, the Contractor shall provide and install protective fencing. Install erosion control material as needed and directed by the COR.

4. Mulching: Spot mulch (to be defined in solicitation)

5. Site Excavation: Site excavation shall consist of the removal and disposal of soil and hard compacted materials, debris, etc. for the purposes of planting. The Contractor shall locate and mark all underground utilities in areas of such work.

6. Planting: Plants shall be installed, as required to replace dead or damaged plants, to retain design intent, or to implement a new design.

The contractor shall locate and mark all underground utilities in areas of work. Plant pits shall be dug one-and-one-half (1 ½) times the dimensions of the root ball. All plants should be set in the pit on a layer of compacted backfill (topsoil or approved soil mixture) vertically and centered accordingly. The most desirable side of the plant shall face toward the prominent view. All air spaces and voids surrounding the root ball will be backfilled to half the depth of the ball, and then tamped to situate the plant in a stable and well aligned position. For B&B plants, excess burlap, tying cord, and wire baskets shall be folded back or removed accordingly. All plastic wrapping shall be completely removed before the placement of backfill. Remainder of pit shall then be backfilled conforming to the established grades, tamped, and watered thoroughly, all within the same planting day. Care shall be taken during handling, backfilling, tamping, and watering to avoid plant damage, especially cracking or breaking of the root ball.

a) Excavated Material and Plant Packaging: All unused excavated material shall be removed from the planting area and seals, tags, cord etc. shall be removed from the plants and disposed of by the Contractor off site.

b) Planting: Smaller plants, such as herbaceous perennials, bulbs, and ground covers shall be planted in holes large enough to allow for spreading of roots at depths recommended for each type of plant.

c) Pots: Potted plants shall be removed from containers, including peat pots, before planting. All containers shall be properly disposed of by the Contractor off site.

d) Included Activities: Plants may be pruned, sheared, wrapped, guyed, and staked (2”X2’X8’ oak stakes only). At the time of installation, all plants shall be watered, edged, and mulched in accordance with the standards here-in.

e) Warrantee: The Contractor shall be responsible for the period of the contract to maintain and guarantee all plants. Plants that are dead, unhealthy, or unsightly shall be removed immediately by the Contractor, at no additional costs, except those determined by the COR to be the responsibility of the Government, in which case, the Government will fund their replacement.

f) Support Apparatus Removal: All support stakes, support apparatus, and wrapping shall be removed after one (1) year from date of installation.

g) Material Handling: Upon delivery, the Contractor shall be responsible for the unloading, placing, and if necessary, the sustaining of all plant material prior to planting.

7. Transplanting: Plants shall be transplanted, as necessary, to protect plants from damage, to retain design intent, or to implement a new design. Plants shall be dug with a firm ball, retaining as many fibrous roots as necessary to assure full recovery. The root ball shall be wrapped in burlap and tied and transported carefully to avoid cracking or breaking.

Plants shall not be handled by the trunk or stems, and the roots or balls of all plants shall be protected from the sun, drying winds, and frost. Care should be taken to keep the root ball moist. Perennials to be transplanted and/or divided shall be dug far enough from the plant to include all roots without damaging them. Plants shall be pulled apart with each division or crown cut with its own roots intact. Each division shall be reset into well prepared soil that has good drainage and amended with compost and/or leaf mold.

a) All plants shall be planted, maintained, and guaranteed (to be clarified in the solicitation). Disturbed areas from where plants were removed shall be backfilled with topsoil, tamped, raked, and shall be covered with either mulch or sod or seed as approved by the COR.

8. Furnishing gravel: Gravel shall be provided for planting and drainage purposes. Gravel shall consist of one (1) to two (2) inch washed gravel composed of hard durable pieces of stone, thoroughly clean, and free from extraneous and or deleterious matter.

9. Related Services: The Contractor shall provide the necessary labor, materials, and equipment to perform landscape related work that is not specifically covered under this contract, such as, but not limited to:

policing ornamental beds, cabling and bracing trees; re-staking plants and, in times of drought, watering plants using a water truck and /or other appropriate means.

10. Plant Removal: The Contractor shall remove shrubs and trees, including stumps, which are dead and/or pose a threat to public safety, or are identified by the COR. Disturbed areas where plants were removed, shall be covered with either mulch or sod, as approved.

11. Soil Tests.

12. Landscape Design: Partial or total landscape designs for sites under this contract. These include all or some of the following: blackline drawings, and colored presentation renderings. This work may be subcontracted.

13. Irrigation System Design: Design a completely automatic irrigation system. Design shall be completed by a Certified Irrigation Designer.

Estimate of total water usage per zone per month shall be provided. The exact location of the pump and the control box must be approved by the

COR and Building Manager. Once installation has been completed and accepted, three (3) hard copies and one electronic copy of the as built drawings, included a list of all installed equipment must be provided to the

14. Irrigation Repair: Repairs shall be paid through Additional Services.

Related services shall cover costs of pipes and wire repair, controller, solenoid valve and sprinkler head replacement and any other repairs necessary. Repairs shall be performed by a Certified Irrigation Contractor and completed within 48 hours; delays in this schedule must be approved by the COR.

Q. BIO PREFERRED MATERIAL: The Contractor shall utilize products and materials made from bio-based materials to the maximum extent possible without jeopardizing the intended use or detracting from the overall quality delivered to the end user. All supplies and materials shall be a type and quality that conforms to applicable federal specifications and work standards. All supplies and materials to be used in the performance of work described here-in are subject to the approval of the COR. See www.biopreferred.gov . The following is a list of products that may be used in this contract for grounds maintenance for which bio-based products are available: fertilizers and 2-cycle engine oil.