Over Seeding Your Lawn
Lawn growth, 20 hour time lapse
Spring is the perfect time to over seed your lawn. The cool temperatures & spring moisture are ideal conditions for germination. Over seeding is generally defined as casting seed onto an existing lawn. This is a great way to add thickness to a thinning area and rejuvenate older lawns with newer more heat and drought tolerant species of grass. Here in Colorado we use cool season grasses such as Kentucky Bluegrass, Fescue, and Rye Grass. New mixtures of these grasses are being bred constantly to help improve lawn color, traffic resistance, and most importantly for Colorado, drought tolerance. Our Blue Carpet blend, which consists of 5 different verities of Kentucky Blue grass, is a great choice that will perform well in our climate. http://www.earthcarpet.com/products_blue_carpet.aspx
Step 1: Preparing your lawn.
The steps for over seeding are very similar to seeding a new lawn. In a new lawn you would normally rototill in 1-2” of compost 4-6” deep and rake it smooth. This obviously won’t work for an existing lawn, but lightly raking the soil and or aerating before adding seed is advisable. This will score the surface of the current soil allowing for seedlings to take root easier. It will also help to remove excess thatch that may have built up. Thatch is just old dead grass and roots that exist on the top levels of sod. Most lawns suffer from soil compaction it would be wise to core aerate your lawn before laying down your grass seed. By removing plugs in your lawn you accomplish adding much needed oxygen to the soil and grass seed loves to germinate in the tiny cozy holes all over the lawn. Colorado soil has an abundance of clay so we recommend having your lawn aerated twice a year (in the spring and fall) Once you have prepared your lawn for over seeding it is now time to select and sow your seed.
Be sure not to apply any pre emergent for weeds in early spring as this would prevent your seeds from germinating
Step 2: Selecting your Grass Seed
Not sure what kind you need? Not a problem. Just bring in a sample (about palm size) and a Nick’s nurseryman will identify what kind of grass you have on the spot. Most Coloradoans have a Kentucky Bluegrass/ Fescue blend. Once it is clear which type of grass seed you need it is time to lay it down.
Step 3: Lay your seed
To lay your seed Nick’s advises using a hand spreader that will broadcast seed evenly over your lawn. You may already have a hand spreader that you use for fertilizer, when using seed just change the setting to SEED, usually the lowest setting. Now lay your seed using your spreader being sure to cover all areas desired.
Step 4: Top-Dress your Seed
Once the seed is laid down it is important to lay down a THIN layer of decomposed organic material such as a compost/topsoil mix or Scotts seeding soil available at Nick’s. Now this may sounds contradictory to all the previous steps to remove all the thatch but it is VERY different. DECOMPOSED organic material is actually very beneficial to our soils; adding nutrients and breaking up the Colorado clay. When top-dressing avoid using a “hot” manure that can burn tender roots, be sure to use a well composted soil like Nick’s boss planter mix sold in bulk or the Scotts seeding soil available in a bag. The soil layer will also protect your new seed from birds and MOST importantly help retain moisture. Remember to use a THINlayer. The compost only needs to be about ¼ ” thick. Any thicker than that and you will run the risk of smothering the grass seed, preventing germination.
Step 5: Water
THE MOST IMPORTANT and final five steps in the process are water, water, water, water, water. New grass seed needs FREQUENT but lightwatering. The biggest hurdle and most common reason for poor seed germination is due to drying out. That being said the seeds do not need immense AMOUNTS of water just frequent applications of it. We recommend at least three times a day if possible but only for 3-5 minute increments for pop up sprayers and 7-8 minutes for traditional impact rotors or pop up rotors. Heavy water applications are unnecessary and could wash away seed and loose soil so take into account the grade of your lawn. A steep grade may require more frequent but shorter cycles to keep seeds moist but not washed away.
Grass seed can take an average of 3-4 weeks to germinate. During this time it is best to keep traffic off the area as much as possible. Newly germinated seedlings are delicate and when crushed can die completely. Sometimes it is best to place a temporary barrier around the area and seed the lawn in steps to keep you lawn usable. Since the area of your new lawn will need to be protected from traffic (and lawn mowers) for a few weeks it is a good idea to mow your lawn short prior to over seeding. This will also help your existing lawn avoid becoming matted and it will push through the protective layer of compost you laid down.
- Mow lawn short
- Lightly Rake area
- Spread ¼ - ½” of top soil or seeding soil (interchangeable with spreading seed)
- Rake topsoil even
- Spread new grass seed evenly
- Top dress with a thin layer of topsoil
- Immediately water seed in lightly
- Water newly seeded area at least 3 times a day for short increments. Less may be needed when temperatures are cool.
- Avoid traffic in the area.
- Enjoy your beautiful lawn
- Fertilize with Pro-rich lawn fertilizer 1 month after sowing
Adding organic material can be done PRIOR to laying down the seed if you wish to add more than a thin layer. This is called top dressing and is a great idea to help battle the poor soil profiles we face here in Colorado. It is important to remember that a thicker layer can smother existing grass. We advise to add no more than an inch of LOOSE organic material. Topsoil and topsoil/compost blends are much denser and may compact smothering your existing lawn. When you are finished spreading your top dressing, rake it smooth. Any bumps or swales that are present will forever remain once your grass grows through it and the new grass seed takes root. Once raked, the new material will be loose and grass seed may be spread directly on top of it and lightly watered in. The water will work the new grass seed to the desired depth. If you decide to wait to spread your grass seed, re-rake the area or spread out a thin layer of compost out after the seed is spread and water in.