Landscaping Tips - Ideal Time to Overseed

When is the ideal time to overseed your bermudagrass lawn with perennial ryegrass? 

Grass seed germinates faster and grows stronger when the planting season aligns with the natural germination and growth processes of the plant. The influences on germination and growth include both environmental conditions (which the turf manager controls to some degree) and inherited influences in the seed.  Perennial ryegrass seeds have a very quick germination rate, (the seeds should germinate within 5 to 10 days) so if the temperatures are right and the water and seed-soil contact are there, the overseeding operation should be successful.

· Air temperature-wise, overseeding should be done when the daytime temperatures are 80-85°F and the nighttime temperatures are 55°F. weather.com provides monthly high and low temperatures for Phoenix and Arizona over a three-year period.  Last year, 2020, these ideal temperatures did not happen until the last week of October. This year, 2021, the prediction for the ideal temperatures occurs the third week of October.  Check the weather over the next few months to schedule the best time to start the overseeding  process. 

· The soil temperatures should be between 50°F and 65°F.  An inexpensive soil thermometer, available at most garden stores, can help eliminate the guesswork. Check the temperature six inches down into the soil. 

· Sowing the seed too early in the fall shall result in poor germination, birds feeding on the seed, increased competition from weeds and slowing of the bermudagrass dormancy. 

· Sowing too late in the fall, may slow germination as well as growth and establishment of the seedlings and the first frost may damage or kill them.

Proper soil preparation is also key to the germination process.  Much of the initial growth of new grass seedlings happens underground, where it cannot be seen. The seeds must come into contact with the soil so that new roots get seedlings firmly established.

With the challenging climatic changes occurring in our area today, flexibility in adjusting the dates for turf overseeding are key to not only a successful operation but to saving money in labor and seed if multiple visits are necessary to achieve an acceptable lawn.