Scheduling Fall Seedings for Cold-Climate Revegetation
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
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Revegetating construction sites in the fall requires the scheduling of seeding and mulching for either permanent or dormant seedings. Dormant seedings must be late enough in the fall to prevent germination, while permanent seedings must be early enough to permit seedling establishment and avoid winterkill. A technique for determining optimum seeding dates using growing degree-day curves was developed and tested. Small outdoor plots and buried pots in Hanover, New Hampshire, were seeded with tall fescue at intervals during October 1988 and 1989, respectively, and covered with either straw mulch or a Typar row cover. Soil surface temperatures, germination and growth were monitored into the following springs. Fall or spring germination of fall-sown tall fescue seeds required about 100 GDDs over 5C, while the development of a second leaf required an additional 70 GDDs. In the experimental plots without any cover, these requirements were met with 12 October and 5 October seedings, respectively with a Typar cover, seeding dates could be delayed by one week. In pots the greatest spring yields were obtained under Typar at the earliest 5 October seeding date and the latest dormant seeding date 2 November. Straw mulch applied during the fall had little or no effect on the number of growing degree-days remaining. However, during the following spring, it slowed soil warming and germination of dormant seedings. The appropriate fall seeding date for northern areas can be calculated using a power curve for Hanover, New Hampshire Julian date 360 x GDDs required to the minus 0.05 power.
- Agronomy, Horticulture and Aquiculture