Category Archives: Seeding

Fall Dethatching & Overseeding

Everyone wants that lush green and full lawn. For northern cool season grasses, the closest thing to a get rich quick lawn solution is to fall dethatch and overseed. It will create the biggest impact difference to your lawn and is fairly easy.

The Preparation:

To do the dethatching for most yards under 20,000 sq ft you can easily knock this out with a simple DIY electric dethatcher like the one SunJoe sells for typically between $130-180. We like it for its price (as cheap as renting a beast of one from Home Depot for a few hours), and for its effectiveness. Check out the thatch coming up in the quick video below. Removing all of that buildup will allow water and nutrients to better reach the soil to be more effective. This will also prep your soil for better seed to soil contact when overseeding.

Dethatcher Rake

Type of Grass :

When picking your grass type for the fall overseed you need to decide what is best for your lawn. We like the idea of introducing more Kentucky bluegrass (AKA – KBG) blends into the lawn for their ability to expand growth and fill in gaps in the lawn. You can READ MORE ABOUT GRASS TYPES HERE. One brand we enjoy using is from and comes at a fair price.

Lawn Renovation Steps & Video From This Old House:
1. Mow the lawn to a height of 1½ inch. Be sure to collect the grass clippings.
2. Run a de-thatcher across the entire lawn to remove dead plant matter. (WE LIKE THE SUNJOE!)
3. Use a leaf rake to collect and remove all the thatch pulled from the lawn. Some people use a leaf blower or run their lawn mower over after raking to pick up the extra piece in their bagger.
4. Run a gas-powered core aerator across the lawn. (WE ACTUALLY SKIP THIS STEP, UNLESS YOU HAVE REALLY COMPACT SOIL)
5. Rake up and remove the soil plugs extracted by the aerator. (IF YOU DID THIS)
6. Spread compost over the lawn and rake it down into the holes. Even if you did not core aerate compost or peat moss is a really nice introduction of organic matter to the soil.
7. Analyze the physical structure of the soil with a soil test kit; amend the soil as necessary. (LAWN SERV’S JOB!)
8. Use a broadcast spreader to over-seed the lawn with new grass seed. Adjust the spreader to dispense seven pounds of seed per 1,000 square feet area.
9. Use backside of leaf rake to lightly work the grass seed into the lawn.
10. Lightly water twice a day to keep the lawn damp, not soaking wet.

Overseeding – Cool Season Grass in the fall

BACKGROUND: Overseeding is the action of adding grass seed to an existing lawn. This may be considered by people for spots where bare areas show, or even better over the whole yard! Overseeding is a great way to improve the density of grass that has become thin while introducing new innovative grass that is likely more resistant to disease, drought, and bugs.

THE RULE (KIND OF): if 50% or more of you lawn is in good condition, overseeding can be a positive effort worth trying. If more than 50 percent of the area is in poor condition (weeds, dog spots, etc), you will want to consider a new lawn from sod or seed (bigger project).

NOTE: Pick seed that is appropriate for your lawn type and area. You probably want to make sure you are buying perennial not annual grass so that it comes back the next year. It will say right on the label of the bag.

Best Practices:

MOW LOW: We don’t typically advise this…. but because you are trying to grow grass from seed take into consideration that the seed will be competing with that existing (taller) grass and its nutrients (sunlight, water, fertilizer, etc). To give the seed a better chance MOW LOW in gradual steps. Normally, you should cut grass to a height of 3 to 3.5 inches. In this case, reduce that height to 1.5 to 2 inches. Also, bag or rake up the clippings in preparation for overseeding lawns, even if normally you do not. You want to give seeds the best chance of making good contact with the soil, and clippings would just get in the way.

RAKE TO LOOSEN SOIL: You will need good seed-to-soil contact for the new seed to germinate. Prepare areas by raking. Use a light touch, so you break up the soil surface without raking out the existing grass.

RAKE TO HELP SEED SOIL CONTACT: We recommend applying seed with a spreader to get more even coverage. Use the recommended rate for your selected seed when overseeding. Rake the area again lightly with an upside down rake after you overseed to improve the seed-to-soil contact.

APPLY STARTER FERTILIZER: apply a starter fertilizer for improved and faster results. We think going half application rate 2 weeks apart is a real pro move if you have the time.

WATER, WATER: The grass seed must be wet in order to germinate. The soil should be kept evenly moist, which may mean several water applications per day for a few weeks. Try not to over do the watering leading to flooding the area and making the seed move.

After the grass blades sprout, you’ll still need to water a couple of times per day and try to take it easy on the lawn for the first couple mows. Definitely don’t go heavy traffic, it will die. Keep up with your regular fertilizer applications and enjoy!

The best time for overseeding lawns that have cool-season grasses is in September in northern climates. You are looking for that not too hot, not going to frost too soon time frame.