Skip to main content


Home > Resources > Late Summer Seeding

Timely Tip – Late Summer Seeding

Late Summer Is The Best Time of Year To Seed The Lawn

While spring and early summer seeding should be avoided, late summer /very early fall (Aug 15—Oct 7) is THE time for seeding in southeastern Pennsylvania, whether you are establishing new plots, repairing drought and summer damage,  or over-seeding to introduce newer varieties of seed with better drought, disease, shade or insect tolerance.  The advantages of late-summer seeding include warm soil temperatures for good germination, less weed competition and diminishing summer heat and drought stress.  By comparison, spring seeding conflicts with crabgrass and weed control applications and leaves very little time for seedlings to mature before they must endure the heat, drought and other stresses associated with summer.

Seed Selection

Your selection of seed should be guided by conditions such as full sun, dry shade, poor soil, sloping terrain, heavy foot traffic or a lawn’s history of insect and disease problems.  Take time to identify the issues affecting the performance of your lawn before selecting seed.  Grass seed has advanced a long way in recent years, and it is now possible to purchase, for example, endophyte-enhanced seed for insect resistance.  Weed Man can help identify issues in your lawn and make grass seed suggestions.  We recommend purchasing seed from knowledgeable, local suppliers who can provide the best seed for your lawn conditions:  Uhlers Seedsmen, 160 Lancaster Ave, Malvern, PA (ph) 610-644-1945 or Sweeney Seed Company, 488 Drew Court, King of Prussia, PA (ph) 610-275-2710    


Existing lawns - It is extremely important that your seed be in contact with soil, as opposed to dead, thatch material in the lawn.  For large areas aeration is the most practical means of penetrating thatch to get the seed to the soil.  Nearly all germination will occur within the protected aeration holes, which is fine.  As the seedlings mature through the fall and following spring, the spacing is sufficient to develop a thick lawn.  
New or bare areas larger than 12-18” in diameter - Remove any thatch and apply seed to finely cultivated topsoil you have either added or worked and loosened to a depth of 1”.  After applying seed, mulch with straw to keep the seed shaded, moist and protected from the elements.   

Starter Fertilizer

Weed Man’s regularly scheduled fertilizations provide adequate nutrients for late-summer seeding.  A “starter fertilizer” is not necessary.

Ideally, germinating seed should be constantly moist.  You should provide light, frequent watering when precipitation does not suffice.  When large existing lawn areas are aerated and over-seeded, the homeowner often makes a conscious, practical decision to water the most critical areas and accept the results that natural precipitation yields in other areas.

Many varying factors affect the short- and long-term success of a seeding.  Areas of young grass are more susceptible to the hardships of weather, competition, and traffic than established stands.  To avoid frustration, we encourage you to talk with us about establishing realistic expectations for a particular seeding project.  In general, when seeding your lawn to improve performance, a realistic expectation would be that you’ll have to seed in 2 or 3 years out of the next 4 or 5 years.