Section 13     Highway Seeding

13.1 General

Section 13 is intended to assist those seeding contractors who must conform to Maryland State Highway Administration (MD-SHA) requirements for highway seeding. Current MD-SHA seeding specifications are paraphrased here; contact Maryland Dept. of Transportation for current MD-SHA specifications when bidding or specifying work.

13.2 Soil Testing

MD-SHA requires soil testing. Soil shall be tested for acidity (pH), soluble salts concentration, phosphorus (P or P2O5), and potassium (K or K2O).

13.3 Salvaging Topsoil

Topsoil shall be removed from areas and to depths as specified by MD-SHA. areas as specified by MD-SHA. Topsoil shall be transported and stored in piles at locations acceptable to MD-SHA. Topsoil infested with seeds, rhizomes, etc. of Johnsongrass, Canada Thistle, or Phragmites shall be evaluated by MD-SHA prior to salvaging, which shall determine the severity of infestation, how the topsoil shall be used, and steps to prevent spread of these weeds. Vegetation shall be removed before topsoil is removed. Topsoil shall be kept separate from other materials in neat piles on well drained land, and shall be seeded with MD-SHA conservation seed mixture immediately after final pile shaping. Silt fence shall be installed and maintained around the stockpile until vegetation is established. Excess topsoil is the property of MD-SHA and shall not be removed without written permission of MD-SHA.

13.4 Placing Salvaged Topsoil

MS-SHA shall reevaluate salvaged topsoil infested with seeds, rhizomes, etc., of Johnsongrass, Canada Thistle, or Phragmites prior to placing. Before salvaged topsoil is placed, the existing grade shall be loose and free of stones, etc. larger than 3 inches (80 mm). Subject to the suitability of weather and soil conditions, as specified by MD-SHA, salvaged topsoil shall be worked into the existing grade; roughening, ridging, or serrating the existing grade may be specified by MD-SHA. Salvaged topsoil shall be placed to a depth specified by MD-SHA. Stones, etc. larger than 3 inches (80 mm) shall be removed. Slopes with steepness of 1:2 to 1:4 shall be tracked perpendicular to the slope with cleated track equipment. Limestone and soil amendments shall be added as specified by MD-SHA.

13.5 Soil Preparation Prior to Seeding

For turf seeding, wildflower seeding, woody shrub seeding: Areas shall conform to MD-SHA specifications for the finished grade and be free of plant growth before soil preparation is begun. The soil of areas to be seeded shall be loosened by disking, harrowing, raking, or by other methods approved by MD-SHA immediately before seeding, or as specified by MD-SHA. Where slopes are shallower than 3:1, the soil shall be loosened to a depth of 2 inches (50 mm); where slopes are 3:1 or steeper, the soil shall be loosened to a depth of 1 inch (25 mm); where serrated cut are present, slopes shall not be loosened, but shall be seeded and mulched in vertical increments no greater than 50 feet (15 m). Clods, stones, etc. larger than 1.5 inches (40 mm) shall be removed before seeding in or near residential areas; in other areas, only debris over 3 inches (80 mm) shall be removed. Gullies, washes, and disturbed areas that develop after final soil preparation shall be repaired before seeding.

13.6 Seed Application Equipment

Spreaders, drills, hydraulic seeders, etc. shall be approved by MD-SHA, and calibrated to the satisfaction of MD-SHA. Hydraulic seeders shall display maximum capacity in gallons (liters), shall have an agitation system, and shall spray uniformly. Mechanical seeders shall be capable of placing seed at rates specified by MD-SHA. Hydraulic seeders and spinner spreaders shall not be used during periods of high winds.

13.7 Seeding and Fertilizing

Seed and fertilizer shall be applied to previously prepared seedbeds. Legume seeds shall be inoculated according to the manufacturers label; inoculant shall be stored at room temperature (about 65o F), out of sunlight and away from heating units. Hydraulic seeders shall apply seed within 8 hours after mixing. Hydraulic seeders shall use inoculant rates 10 times greater than for mechanical seeders; seed shall be reinoculated if not used within 1 hour. Mechanical seeders shall incorporate seed and fertilizer no deeper than 0.25 inches (6 mm). Legume seed shall be dampened with water and mixed with inoculant; seed shall be reinoculated if not used within 24 hours.

13.8 Fertilizer

MD-SHA specifies the use of these fertilizers:

10-22-22 50% urea formaldehyde nitrogen, phosphorus, and potassium, for topsoiled and nontopsoiled areas
38-0-0 urea formaldehyde, for nontopsoiled areas
0-20-20 phosphorus and potassium, for refertilization
38-0-0 urea formaldehyde for refertilization

13.9 Limestone

MD-SHA specifies the use of these liming materials:

MD-SHA Region Liming Material Kilograms per Hectare

Tons per Acre

1 Limestone 6,700 6.0
2A and 2B Limestone 5,600 5.0
3 Dolomitic Limestone 4,500 4.0

13.10 Seeding Regions

MD-SHA seed mixtures are to be seeded in these regions..

Region 1 (Western): Garrett County; Allegany County; Washington County, west of Clear Spring.

Region 2A (Northwestern): Washington County, east of Clear Spring; Frederick County.

Region 2B (Northern): Montgomery County, Carroll County, Howard County, Baltimore County, Baltimore City, Harford County, Cecil County.

Region 3 (Eastern): Prince Georges County, Anne Arundel County, Calvert County, Charles County, St. Marys County, Kent County, Queen Annes County, Talbot County, Caroline County, Dorchester County, Wicomico County, Worchester County, Somerset County.

13.11 MD-SHA No. 1 Seed Mix for Roadsides

MD-SHA No. 1 Seed Mix for Roadsides is formulated and tested according to strict standards of purity, minimum germination, and composition. MD-SHA No. 1 shall be mixed under the supervision of Md. Dept. of Agriculture, and shall be tested and tagged by MDA with appropriate certificates of identity (i.e., tags). MD-SHA No. 1 shall carry the MD-SHA orange tag on its containers when it is seeded. MD-SHA No. 1 shall be modified according to the seeding season and the seeding region. MD-SHA No. 1 shall be composed of the following turfgrass species, and be seeded at 75-100 lbs./acre. Certified cultivar(s) of Tall Fescue = 90%; certified cultivar(s) of Kentucky Bluegrass = 10% of mix.

Tall Fescue, certified cultivar(s) = 90% of mix

Any of the following cultivars: Alamo, Amigo, Anthem, Apache, Apache II, Arriba, Austin, Avanti, Aztec, Barlexus, Bonanza, Bonanza II, Chieftain, Chieftain II, Cimmaron, Coyote, Crewcut, Crossfire, Crossfire II, Debutante, Duke, Duster, Eldorado, Falcon II, Finelawn 5GL, Finelawn 88, Finelawn, Petite, Grande, Guardian, Heritage, Houndog V, Jaguar II, Jaguar 3, Kentucky-31, Lancer, Maverick II, MB-22, Mesa, Micro DD, Minimustang, Monarch, Montauk, Olympic II, Palisades, Phoenix, Pixie, Pyramid, Rebel 3D, Rebel II, Rebel Jr., Safari, Shenandoah, Shortstop, Silverado, Southern Choice, SR-8200, SR-8300, Starlet, Taurus, Titan, Titan II, Tomahawk, Trailblazer II, Tribute, Vegas, Virtue, Winchester, Windsor II, Wrangler

Kentucky Bluegrass, certified cultivar(s) = 10% of mix

Any of the following cultivars: Allure, Barcelona, Baron, Calibur, Cannon, Chateau, Cheri, Classic, Columbia, Dawn, Eagleton, Eclipse, Estate, Fairfax, Freedom, Georgetown, Kelly, Kenblue, Liberty, Limousine, Livingston, Lofts 1757, Marquis, Monopoly, Nassau, Preakness, Ram I, Rugby, Shamrock, Sophia, SR-2000, Suffolk, Unique, Viva, Voyager, Washington

13.12 MD-SHA No. 2 Seed Mix for Medians

MD-SHA No. 2 Seed Mix for Medians is formulated and tested according to strict standards of purity, minimum germination, and composition. MD-SHA No. 2 shall be mixed under the supervision of Md. Dept. of Agriculture, and shall be tested and tagged by MDA with appropriate certificates of identity (i.e., tags). MD-SHA No. 2 shall carry the required MD-SHA orange tag on its containers when it is seeded. MD-SHA No. 2 shall be modified according to the seeding season and the seeding region. MD-SHA No. 2 shall be composed of the following turfgrass species, and be seeded at 75-100 lbs./acre. Certified cultivars of Kentucky Bluegrass = 60%; certified cultivar(s) of Fine Fescue = 40% of mix.

Kentucky Bluegrass, certified cultivar(s) = 60% of mix

Two or more of the following cultivars, with no more than 35% of one cultivar: Abbey, Allure, Alpine, Aspen, Barcelona, Barmax, Baron, Baronie, Blacksburg, Calibur, Cannon, Chateau, Cheri, Classic, Columbia, Conni, Dawn, Eagleton, Eclipse, Estate, Eva, Fairfax, Fortuna, Freedom, Georgetown, Glade, Gnome, Julia, Kelly, Kenblue, Liberty, Limousine, Livingston, Lofts 1757, Marquis, Merit, Midnight, Monopoly, Nassau, Nu-Star, Opal, Opti-green, Preakness, Princeton 104, Ram I, Rugby, Shamrock, Sophia, SR-2000, SR-2100, Suffolk, Touchdown, Unique, Viva, Voyager

Fine fescue, certified cultivar(s) = 40% of mix

Any of the following cultivars: Atilla, Aurora, Banner, Bardur, Bighorn, Biljart, Bridgeport, Brigade, Discovery, Epsom, Eureka, Jamestown II, Longfellow, MX-86, Proformer, Reliant, Scaldis, Serra, Shadow, Silvana, Southport, SR-3000, SR-3100, SR-5000, Tiffany, Valda, Victory, Waldorf, Warwick

13.13 MD-SHA No. 3 Seed Mix

MD-SHA No. 3 Seed Mix is formulated and tested according to strict standards of purity, minimum germination, and composition. MD-SHA No. 3 shall be mixed under the supervision of Md. Dept. of Agriculture, and shall be tested and tagged by MDA with appropriate certificates of identity (i.e., tags). MD-SHA No. 3 shall carry the required MD-SHA orange tags on its containers when it is seeded. MD-SHA No. 3 shall be modified according to the seeding season and the seeding region. MD-SHA No. 3 shall be composed of the following turfgrass species, and be seeded at 75-100 lbs./acre. Certified cultivar(s) of Hard Fescue = 75%; certified cultivar(s) of Chewings Fescue or Sheep Fescue = 20%; certified cultivar(s) of Kentucky Bluegrass = 5% of mix.

Hard Fescue, certified cultivar(s) = 75% of mix

Any of the following cultivars: Attila, Aurora, Bardur, Biljart, Brigade, Discovery, Eureka, Reliant, Scaldis, Serra, Silvana, SR-3000, SR--3100, Valda, Warwick

Chewings Fescue or Sheep Fescue, certified cultivars = 20% of mix

Any of the following cultivars: Banner, Bighorn, Bridgeport, Epsom, Jamestown II, Longfellow, MX-86, Proformer, Shadow, Southport, SR-5000, Tiffany, Waldorf

Kentucky Bluegrass, certified cultivar(s) = 5% of mix

Two or more of the following cultivars: Abbey, Allure, Alpine, Aspen, Barcelona, Barmax, Baron, Baronie, Blacksburg, Calibur, Cannon, Chateau, Cheri, Classic, Columbia, Conni, Dawn, Eagleton, Eclipse, Estate, Eva, Fairfax, Fortuna, Freedom, Georgetown, Kelly, Kenblue, Liberty, Limousine, Livingston, Lofts 1757, Marquis, Merit, Midnight, Monopoly, Nassau, Nu-Star, Opal, Opti-Green, Preakness, Princeton 104, Ram I, Rugby, Shamrock, Sophia, SR-2000, SR-2100, Suffolk, Touchdown, Unique, Viva, Voyager, Washington

13.14 MD-SHA Seed Additives

The following additives shall be added to SHA Seed Mix No.1 and SHA Seed Mix No. 2, as required. Seed mixes which include a one or more seed additive are noted with a suffix using the guide, below:

Suffix Seed Additive Rate per Acre
a = Weeping lovegrass 2.0 pounds
or Foxtail millet  10.0 pounds
b =  Cereal rye 22.0 pounds
c = Crown vetch 8.0 pounds, plus inoculum
d = Serecia lespedeza 20.0 pounds, plus inoculum

13.15 MD-SHA Seeding Schedule

MD-SHA Seed Mix No. 1 and MD-SHA Seed Mix No. 2 shall be seeded according to the schedule, below. Letters a, b, c, d refer to Seed Mix Additives, see above.   

Region Spring Season Summer Season Fall Season Late Fall Season
1 1 April - 15 June 16 June - 31 July 1 August - 1 October 2 October - 1 November
SHA-1c or SHA-2 SHA-1ac or SHA-2a  SHA-1c or SHA-2 SHA-1bc or SHA-2b
2A 1 March - 15 May 16 May - 31 July 1 August - 20 October 21 October - 20 November
SHA-1c or SHA-2 SHA-1ac or SHA-2a SHA-1c or SHA-2 SHA-1bc or SHA-2b
2B 1 March - 15 May 16 May - 31 July 1 August - 20 October 21 October - 20 November
SHA-1d or SHA-2 SHA-1ad or SHA-2a SHA-1d or SHA-2 SHA-1bd or SHA-2b
3 3 March - 1 May 2 May - 31 July 1 August - 31 October 1 November - 30 November
SHA-1d or SHA-1 SHA-1ad or SHA-1a SHA-1d or SHA-1 SHA-1bd or SHA-1b

13.16 Legume Cultivars for MD-SHA Seeding

The following legume cultivars have been specified for use in certain seeding mixes by MD-SHA.

Birdsfoot trefoil Empire, Norcen, Viking
Crimson clover
Crown vetch Penngift, Chemung
Flatpea Lathco
Serecia lespedeza Appalow, Interstate, Interstate 76

13.17 Miscellaneous Grass Cultivars For Highway Seeding

The following grass cultivars have been specified for use in certain seeding situations by MD-SHA.

Alkali grass Fults, Salty
Canada bluegrass Reubens
Perennial ryegrass All-Star, Blazer, Manhattan, Palmer, Pennant, Pennfine, Premier, Prelude, Regal, Repell
Redtop Streaker
Reed canarygrass

Ioreed, Palaton, Rise

Roughstalk bluegrass Laser, Sabre
Weeping lovegrass common, Lehmann, Morpa

13.18 MD-SHA Temporary Seeding Mix

MD-SHA Temporary Seed Mix: Barley or Cereal Rye = 95% of mix; Foxtail Millet = 5% of mix.

Barley OR Cereal Rye
Minimum purity = 98%
Foxtail Millet
minimum purity = 99%

13.19 MD-SHA Wildflower Seeding

MD-SHA Wildflower Seeding Dates
Region 1 1 September thru 1 May
Region 2A and 2B 1 October thru 15 April
Region 3 15 October thru 15 April

MD-SHA Wildflower and Companion Seed For Regions 1, 2A, 2B

Seed Box A: MD-SHA Wildflower and Companion Seed

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

Black-eyed Susan Rudbeckia hirta 2.2 2.0
Corn Poppy Papaver rhoeas 1.5 1.3
Gold Yarrow Achillea filipendula 0.2 0.2
Ox-eye Daisy Chrysanthemum leucanthemum 1.1 1.0
Plains Coreopsis Coreopsis tinctoria 1.1 1.0
White Yarrow Achillea millefolium 0.2 0.2
Sheep or Hard Fescue Festuca ovina or F. durior 1.1-5.6 1.0-5.0

Seed Box B: Wildflower Seed

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

Cornflower Centaurea cyanus 1.5 1.3
Cosmos Cosmos bipinnatus 1.8 1.6
Dames Rocket Hesperis matronalis 1.7 1.5
Hookers Evening Primrose Oenothera hookeri 0.1 0.1
Lance-leaved Coreopsis Coreopsis lanceolata 2.2 2.0
Purple Coneflower Echinacea purpurea 2.2 2.0
Rocket Larkspur Delphinium ajacis 1.1 1.0

Seed Box C: Fluffy Wildflower Seed (place Gaillardia without awns in Seed Box B)

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

Firewheel Gaillardia pulchella 1.1 1.0
Blanketflower Gaillardia aristata 2.2 2.0

MD-SHA Wildflower and Companion Seed For Region 3

Seed Box A: Wildflower and Companion Seed

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

Plains Coreopsis Coreopsis tinctoria 1.1 1.0
Mexican Hat Ratibida columnifera 1.1 1.0
New England Aster Aster novae-angliae 0.2 0.2
Ox-eye Daisy Chrysanthemum leucanthemum 1.1 1.0
Black-eyed Susan Rudbeckia hirta 2.2 2.0
Corn Poppy Papaver rhoeas 2.2 2.0
Lemon Mint Monarda citriodora 0.7 0.6
Sheep or Hard Fescue Festuca ovina or F. durior 1.1-5.6 1.0-5.0

Seed Box B: Wildflower Seed

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

California Poppy Eschscholzia californica 2.2 1.0-5.0
Tall Cornflower Centaurea cyanus 1.5 1.3
Yellow Cosmos Cosmos sulphureus 0.7 0.6
Cosmos Mixed Cosmos bipinnatus 0.7 0.6
Calendula Calendula officinalis 0.7 0.6
African Daisy Dimorphotheca aurantiaca 1.1 1.0
Scarlet Sage Salvia coccinea 0.7 0.6
Maximillian Sunflower Helianthus maximilliani 0.3 0.3
Lance-leaved Coreopsis Coreopsis lanceolata 1.1 1.0

Seed Box C: Fluffy Wildflower Seed (place Gaillardia without awns in Seed Box B)

Common Name Scientific Name Kilograms / Hectare

Pounds / Acre

Firewheel Gaillardia pulchella 1.1 1.0
Blanketflower Gaillardia aristata 2.2 2.0

13.20 MD-SHA Woody Shrub Seeding

Woody Shrub Mix

MD-SHA woody shrub mix shall have a minimum purity of 98%. MD-SHA Woody Shrub Seed Mix shall be seeded at the rate of 56 kilograms per hectare (50 pounds per acre).

25% Amur Honeysuckle Lonicera maackii
or Tatarian Honeysuckle Lonicera tatarica
20% Bristly Locust Robinia fertilis (inoculant required)
25% Shrub Lespedeza Lespedeza bicolor (inoculant required)
30% Arrowwood Viburnum Viburnum dentatum

also: MD-SHA Cover Companion Seed Mix shall be seeded at 39 kilograms per hectare (35 pounds per acre)
Lovegrass shall be seeded at the rate of 2 kilograms per hectare (1.8 pounds per acre).
or Foxtail Millet shall be seeded at the rate of 11 kilograms per hectare (9.8 pounds per acre).
and Cereal Rye shall be seeded at the rate of 25 kilograms per hectare (22.3 pounds per acre).

MD-SHA Woody Shrub Seeding Season

Woody shrub seed mix shall be seeded as specified in Section 13.1 thru Section 13.8, unless specified otherwise by MD-SHA. Woody Shrub Seed Mix and associated seed may be seeded in any MD-SHA seeding region during the times shown, below, when the temperature is above freezing (32o F, 0o C), and the ground is not frozen:

Region Spring Season Summer Season Fall Season Late Fall Season

Region Spring Season Summer Season Fall Season Late Fall Season
1 1 April - 15 June 16 June - 31 July 1 August - 1 October 2 October - 1 November
2A 1 March - 15 May 16 May - 31 July 1 August - 20 October 21 October - 20 November
2B 1 March - 15 May 16 May - 31 July 1 August - 20 October 21 October - 20 November
3 3 March - 1 May 2 May - 31 July 1 August - 31 October 1 November - 30 November

Wetland Woody Shrub Mix

MD-SHA wetland woody shrub mix shall be used to seed wetland sites. Composition and seeding rate shall be established by MD-SHA for each site where the mix will be used.

Common Name

Scientific Name

Comments (editors notes)
Black Chokeberry Aronia melanocarpa Small shrub, tolerates shade.
Black Haw Viburnum prunifolium Medium shrub, does better in drier spots.
Buttonbush Cephalanthus occidentalis Small shrub, tolerates the wettest spots.
Canadian Serviceberry Amelanchier canadensis Tree, does better in drier spots, Juneberry.
Common Elder Sambucus canadensis Large shrub, Elderberry.
Fetterbush Leucothoe racemosa Small shrub, tolerates acid soils.
Highbush Blueberry Vaccinium corymbosum Small shrub, tolerates shade, acid, drier spots.
Inkberry Ilex glabra Small evergreen holly shrub.
Silky Dogwood Cornus ammomum Large shrub, widely adapted.
Smooth Alder Alnus serrulata Large shrub, does well in very wet spots.
Smooth Witherod Viburnum nudum Medium shrub, does well in drier spots, too.
Southern Arrowwood Viburnum dentatum Medium shrub, does well in drier spots, too.
Swamp Honeysuckle Rhododendron viscosum Does well in wet, acid soils, nice flower.
Sweetbay Magnolia Magnolia virginiana Small tree, partly evergreen, nice flower.
Sweet Pepperbush Clethra alnifolia Small shrub, very showy flowers.
Winterberry Ilex verticillata Small holly shrub, does well in very wet spots.
Witch Hazel Hammamelis virginiana Small tree, does better in drier spots.

13.21 MD-SHA Seed Mulches

Kinds. MD-SHA seed mulch shall be straw or hay, or wood cellulose fiber, or soil stabilization matting.

Straw or hay. The composition of straw and hay used for erosion control seed mulch shall conform to the definitions of the MD-SHA. In addition, straw and hay used for MD-SHA seeding shall be free of the seeds or viable plant parts of the following weeds: annual bluegrass, Bermudagrass, giant foxtail, phragmites, bindweed, cocklebur, corn cockle, dodder, horse nettle, spurred anoda, wild garlic, and wild onion. Straw and hay shall be applied according to the provisions of the MD-SHA and shall be anchored, as may be appropriate, according to the specifications of MD-SHA.

Cellulose wood fiber. Cellulose wood fiber products shall conform to the definitions of the MD-SHA, and be applied according to the specifications of MD-SHA..

Stabilization matting. Stabilization matting products shall have a uniform thickness and distribution of natural or biodegradable synthetic fibers or cords that freely allow the penetration of water and seedlings of the plant species which they cover. These materials shall not contain any chemicals or other materials which may leach into the soil, or reduce the germination and establishment of seeds placed under them, or which may be harmful to skin. They shall be smolder-resistant and resist rotting or decay for a minimum of six months and a maximum of 12 months. The top and/or bottom of shredded wood (excelsior) matting shall be covered with a biodegradable plastic netting.

Staples. Stabilization matting products shall be secured to the soil surface according to the manufacturers label instructions. If staples are used they shall be 11-gauge "U" shaped wire staples (width not less than 1.5 inches, length not less than 6.0 inches), or 8-gauge "T" shaped wire staples (main leg not less than 8.0 inches long, secondary leg not less than 1.0 inch long, and head not less than 4.0 inches wide).