Lawn Aeration and Seeding; BE PATIENT :)
Often homeowners and landscaping outfits consider the unofficial end of summer, namely Labor Day weekend, the opportune time to get out and aerate and seed grassed areas. While this practice will yield results a better use of resources is to wait! The optimal time to aerate and seed with a cool season grass (fescues, ryes, most bluegrasses) is generally between September 15 and October 15. The reasoning behind this line of thinking is three fold: aerating and seeding produces the best results when temperatures have dropped, grasses are actively growing, and weed "competition" is mitigated.
- Sweltering summer days put substantial stress on cool season grasses, even when watered daily. As a general rule of thumb seeding yields best results when the soil temperature reaches 50 to 65 degrees Fahrenheit, which correlates to air temperatures ranging from 65 to 75 degrees. Temperatures are then still warm enough for seed germination without providing too much stress on new (young) grass.
- When temperatures drop going into the fall cool season grasses return to active growth; [core] aeration encourages grasses to develop deeper roots and plant roots need air to survive! Aeration also allows new seed to get down into the soil.
- Weeds that thrive in the summer begin to die as the weather transitions toward winter. This time when warm weather weeds are dying and cool weather weeds have not yet begun growing presents the best time for new grass to take hold.
