Overseeding
Question:
“There is seed just lying there, and it has not grown at all since they planted the seed several weeks ago. Doesn’t the crew need to come out and re-aerate, so the seed can go down into the ground? It’s just laying there and it cannot grow like that.”
Answer:
This is a common misconception for cool season grass aeration and over-seeding. It is common to think that the grass only grows in the aeration holes.
However, in reality, aeration is done to help loosen the soil for roots of the existing grass, as well as the future new growth. The holes allow water, air, and nutrients into the root bed which aids in root health and plant growth. As another benefit, aeration provides an excellent little seed bed for over-seeding, which is one of the reasons these two activities are done at the same time. However, the holes are not necessary for fescue germination in the fall.
In reality, aerators are designed to provide 4-6 holes per square foot. So, let’s do the math. We’ll assume 6 holes per square foot. If each hole is 3/4 square inch, that means that only about 3% of aerated ground has holes. Let’s say we then aerate 3 times in the same area. That is still only 9% of the area that has holes! Or, to think of it another way, after a single aeration, 97% of the ground does not have holes.
So, without question, most of the seed that becomes a “lawn” is established on ground that has not been aerated.
An interesting facet of this, however, is that when adequately watered, seedlings do START in the holes FIRST. This makes sense since, the ground has been loosened and gravity moves water to these holes. The seeds in the holes will initially get the most benefit of the watering. However, with watering diligence, in just a short time after the seed germinates in the holes, seed will begin germinating where there are no holes. (Unless of course there is a situation for another topic such as shade, roots, rocks, etc.)
So the answer to this question and concern is this: Stay diligent with your watering, and have patience. If planted at the right time, and the area has appropriate conditions for fescue turf, the seed will germinate and grow!
Email info@tlgturfcare.com for further questions and information.
Tips from the NCSU Cooperative Extension:
“Tips For Success: Seeding Cool Season Turfgrasses
Fall is the best time for renovation and seeding of tall fescue and other cool-season lawns. Remember that spring-established tall fescue is more susceptible to drought, heat, fungal diseases, and weed encroachment. With normal summer weather patterns, spring seeding is not likely to result in a year-long stand of healthy tall fescue. So do not delay, seed today!
Young seedlings normally emerge and grow best when air temperatures are between 70 and 80 degrees. Soil temperatures need to be greater than 60 degrees for good germination. It is generally better to go a bit early than to seed late. If tall fescue is seeded in less than ideal conditions (too cool or no soil moisture), you may experience a thin turf stand going into the winter. So try to get your seed out in September. If you must wait until October there is an increased likelihood of slow/low germination.
A typical tall fescue seeding rate is 5 to 6 pounds of seed per 1000 square feet. Germination normally occurs within 7 to 21 days under suitable moisture and soil temperatures conditions.”