Improve Denver Landscaping through Overseeding
americanarbor March 11, 2016

In the Denver area, it’s not uncommon for cool season lawns to look less than perfect after summer’s heat or winter’s cruel weather. Lawns at the end of both seasons are subject to damage, disease, and neglect. Fall is considered the optimum time for overseeding, but March offers the second best opportunity to improve Denver landscaping

Overseeding is also a simple way to thicken a thin and tired lawn and a lot less expensive and labor-intensive than replacing old sod with new.  Before overseeding your lawn, have your soil tested. Simply dig up some soil (about two or three cups is sufficient) from several areas of your lawn and put it in a plastic bag. Your local extension office can test the soil for you for a nominal fee.

Correct problems before overseeding: poor soil condition, improper drainage, soil compaction, insufficient water, poor fertility, poor air circulation, insufficient light, excessive thatch, grass varieties unsuitable for your area, and neglect. Many of these problems can be alleviated through lawn aeration.

Overseeding equipment comes in two basic types: slit-seeding and broadcast seeding. A slit-seeder has blades that cut through the thatch and open a shallow, narrow furrow in the soil into which the grass seed is directly deposited. A broadcast seeder sprays the seeds over the lawn. Landscaping pros generally recommend that broadcast seeding be performed in two passes at forty-five degree angles to make a diamond-shaped pattern. A split-seeder uses less seed; a broadcast seeder is faster and easier. If you haven’t the time or inclination to do this yourself, American Arbor Care can overseed your lawn and correct any pre-application problems. (Link:

After overseeding the lawn, new grass seed will sprout in about seven to ten days under adequate conditions. It takes about eight weeks for an overseeded lawn to become fully established. Grass isn’t that fussy, but it does require some care. After overseeding:

  • Water the lawn heavily to drive new grass seed into the soil where it can germinate.
  • Until the grass seeds germinate, water frequently and lightly.
  • After germination, water less frequently, but more heavily for deeper soil penetration to encourage stronger root growth.

Once the overseeded lawn is established, water it at the levels and frequency recommended for the species of grass.

Top Dressing & Pre-emergent Applications

Fertile soil is rich with microorganisms and organic matter. Colorado, in general, is not blessed with rich soil. Wind erosion and lack of rainfall are main culprits in the state’s poor soil quality. Urban and suburban traffic further compact clay-based soils, which impedes water penetration and root growth. Top dressing can have the following benefits:

  • Enrich the soil and reduce the need for fertilizer.
  • Expand the soil and reduce the damage of compaction.
  • Increase the soil’s ability to retain water.
  • Reduce thatch, so water, herbicides, and fertilizer can penetrate the soil.
  • Prevent wildlife from gorging on the all-you-can-eat buffet you just offered by overseeding your lawn.

Pre-emergent herbicide applications can affect desirable plants. Therefore, it’s best not to apply these chemicals soon after overseeding, because the herbicide can kill the newly sprouting grass and negate your efforts to produce a thicker, healthier lawn. Apply the seed first and then wait at least six weeks (eight is better) so the new grass has a chance to develop a good root system before applying the pre-emergent herbicide. Although mulch and rock beds are a great way to keep weeds at bay, you may need to apply pre-emergents to them as well. The herbacide makes a 1/2″ barrier in the soil and prevents weeds from germinating, but doesn’t kill existing plants. Make sure to ask your Denver tree specialsts which pre-emergent is best for your plants, as some herbicides can damage perennials, including trees. 

How Much Do I Need?

Each application has its own guidelines for application. Don’t apply too much herbicide: it’s expensive and will not provide any additional benefit. Don’t apply too heavy a top dressing or you’ll smother the lawn. In fact, over-application may harm your lawn and other landscaping plants. Applying too little is ineffective and wastes effort, time, and product.

Landscaping Denver yards benefits from the knowledge and skills of professionals. American Arbor Care can determine what your soil needs, the correct ratio of grass seed to square footage and the correct amount of top dressings, pre-emergent fertilizers, and herbicides to apply. We will perform the applications at the right time so that your lawn has its best chance to become the envy of the neighborhood. Call (303) 639-8584 to schedule a consultation–and don’t forget to have your trees inspected, too! American Arbor Care is a professional tree service company offering the expertise and knowledge of certified arborists.  Take advantage of our special offer: for all of your 2016 spray and landscaping maintenance needs, prepay by March 31, 2016 and receive a 5% discount!

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