Northwest Lawn Renovation

FIRST AID FOR POOR LAWNS

The first step is to identify the primary cause of lawn deterioration. Drought, compact soil, poor drainage, root competition, excessive shade, inadequate fertility, thatch, improper mowing, poorly adapted grass species, weeds, insects, and diseases may all contribute to poor lawns.

DIFFERENT LEVELS OF RENOVATION

1) Simple: overseeding a small patch of lawn
2) Medium: include power raking and core aeration if soil is compacted or if thatch buildup greater than one-half inch
3) Total: kill undesirable grasses with non-selective herbicide

SHOULD I REPLACE OR RENOVATE MY LAWN?

If soil is excessively compacted or the yard has greater than 50% weed or bare soil, renovation alone won't be sufficient. Starting a new lawn may be the best option if it's necessary to remove existing turf, till, add compost and topsoil, and change the soil grade.

WHEN SHOULD I RENOVATE MY LAWN?

Renovate your lawn in early fall when growing conditions are favorable and weed competition is lower than in spring. In western Washington, the best time for seeding is between September and mid-October. If that's not possible, seed between late March to mid-May as long as soil isn't too wet to work.

STEP 1: Control Undesirable Vegetation

  • Moss: Use an iron-based moss-killer when the moss is moist and green. Remove dead moss by hand, using a thatching rake or cultivator. Apply moss killer at least 3 weeks prior to seeding.
  • Weeds: Remove manually, use soil solarization methods, or kill using a non-selective herbicide that contains glyphosate (e.g., Roundup®). Read instructions to determine the dilution rate and recommended time to wait before reseeding. Avoid weed killers that persist in the soil, such as soil sterilants.
  • Coarse weedy grasses: Lawns with large patches of weedy grass such as velvet grass, orchard grass, or bentgrass are best renovated after killing all vegetation with glyphosate. More than one application will probably be necessary to kill creeping perennial grasses with deep rhizome roots.
  • For best results, weeds and grasses should be actively growing with plenty of leaf surface for the herbicide to cover. If this is not the case, apply a high-nitrogen fertilizer and water frequently for two weeks prior to using an herbicide. If the entire lawn is weeds, spray everything. If only a few patches exist, spray just those weeds.

STEP 2: Debris Removal

  • Follow instructions on herbicide's label and wait to remove weeds until after the weed killer has reached the roots.
  • Set your lawn mower on its lowest cutting height and mow to approximately three-quarters inch tall. Remove all clippings, leaves, and other debris by sweeping or raking. 
  • Remove thatch more than one-half inch deep by vigorous hand raking or use a power rake to expose existing soil. Power rake the lawn in different directions as many times as necessary to remove accumulated thatch. Set height of tines to nick the soil surface one-eighth to one-half inch deep. Where thatch is excessive, remove with a sod cutter. The soil surface should be firm and lightly roughed with all thatch removed so seed can contact soil surface.

STEP 3: Soil Moisture Replenishment

  • Before seeding, thoroughly soak soil to depth of 6–8 inches to replenish soil moisture. This helps ensure young grass seedlings have sufficient water, particularly important in the fall after a dry summer season.

STEP 4: Prepare Soil Surface by Aerating and Leveling

  • Aerate soil to cure compacted soil, create better drainage, and allow nutrients and oxygen to easily reach plant roots. For small jobs, use a hand-held coring aerator; for larger jobs, use a mechanical aerating machine to remove soil plugs. Aerate the lawn thoroughly by going over it 3 to 5 times in different directions. Allow soil plugs to partially dry before breaking them up with a hand or power rake before seeding. Fill the aeration holes with coarse sand or compost to help maintain improved aeration.
  • Level soil and solve other drainage issues by filling low spots with a quality top soil. First, scratch the existing soil's surface so new soil will blend together with existing soil. Fill low spots with top soil up to the existing soil's level, then water to settle. After the new soil settles, add more top soil and water again. Repeat as many time as necessary until new soil is level with the existing soil and no longer settles. 

STEP 5: Soil Test for pH & Fertility

  • A soil test will determine your soil's pH and fertility. Use test results to determine how to best enhance your soil by adding organic nitrogen fertilizer, phosphate, or potassium.
  • Apply an organic fertilizer such as Dr. Earth Super Natural Lawn Food, following package instructions. Use a level-headed rake to work the fertilizer into the top quarter inch of soil.
  • If soil pH is low, apply lime to raise soil pH. If needed lime enhancement exceeds 100 lbs./1,000 sq. ft., apply 100 lbs. now and the remainder the following spring or fall.

STEP 6: Grass Seeding

  • Select a turf grass variety that is well-suited to the Maritime Northwest. Turf-type perennial rye grasses and fine-leaved fescues are well-adapted to western Washington. Less suitable options are Kentucky Bluegrasses, short-lived in the Puget Sound, and Bentgrass, an overly high-maintenance option for the average gardener.
  • Seed at the right rate, since excessive seeding creates too much competition between seedlings. The larger the seed, the higher the seeding rate. Distribute the seed uniformly over the planting area with a hand-held spreader for small jobs or a drop spreader for larger jobs.
  • For uniform coverage, apply half the seed in two separate applications perpendicular to each other.
  • Lightly rake in the seed so it's covered by no more than 1/16 inch of soil with about 10% of the seed showing on the surface.
  • A light application of screened compost—no more than one-quarter inch—may be spread on top to help retain moisture and hide seeds from birds.

STEP 7: Germination and Watering

  • Young seeds and seedlings die quickly if they dry out, so keep seeded areas moist until seedlings are well established. Several light waterings are better than heavier waterings that can either drown the seeds or float them away on sloped areas.
  • Multiple waterings may be necessary on hot days.
  • Germination is dependent on soil temperatures above 50°F, sunlight, and seed variety.
  • Seedlings should start germinating within two weeks, depending on seed variety.
  • Once seedlings have emerged, gradually increase the duration of watering. Watering frequency may be decreased after the lawn is established.
  • Avoid foot traffic on a newly renovated lawn for several weeks after seedlings first emerge.

STEP 8: Let it Grow, Then Mow

  • Wait to mow until after 60% of the grass is 3 to 4 inches tall. Use a sharp mower to mow to grass 2.5 inches tall. Always keep your lawn between 2 to 3 inches tall because this height helps retain moisture and lack of sunlight deters weeds from thriving.
  • Watering: After the lawn is established, water your lawn deeply during all dry periods. Apply 1 to 1.5 inches of water once a week. Do not depend on the light rains of late spring and early summer to provide enough moisture.

MORE TIPS FOR A HEALTHY LAWN

Fertilize and water regularly for a lush, green lawn year 'round.

Apply dolomite lime every six months (25 lbs./1000 sq. ft.) to maintain neutral soil conditions which help reduce moss in shaded or moist lawn areas.

Core aerate annually to prevent the lawn's soil from becoming overly compacted.

Thatch decreases the vigor of turf grasses by restricting water and nutrients from entering the soil. Thatch is the buildup of dead roots, rhizomes, and stems at the soil surface which accumulates over a period of years. It must be removed periodically by mechanical means. Do not allow thatch to become thicker than one-half inch. If it does, use a thatching rake or power rake to remove as much as possible.

Develop a regular plan to fertilize, mow, water, dethatch, and overseed and keep your lawn looking great!