Lawn Care/Establishment/Seed and Sod Preparation/Seedbed Preparation

Establishment of turfgrass areas is most commonly accomplished with seed, although sod can be used. Sod offers the advantage of an "instant lawn" whereas seed takes much longer to produce a green turf. Establishment with seed is much less expensive and less complicated than with sod. The steps involved in establishing a lawn from seed include the following:

Time of Seeding	Fertility
Preparing the Seedbed	Weed Control Fertility
Seeding	Spring Seeding
Mulching	Dormant Seeding
Watering	Seeding a New Lawn
Mowing

Time of Seeding

The best time to seed a lawn is in late summer to early fall. Adequate soil moisture, warm soil, and limited weed pressure allow for excellent seedling growth. Between August 15 and September 15 is optimum seeding time in northern states while September 1 to September 30 is optimum in southern states. You should seed as early as possible within these windows of time. During the fall, waiting even one week later may mean the stand will take two to four additional weeks to mature. Establishment in the spring is possible but not as effective as fall seeding.

Preparing the Seedbed

A soil test should be taken at the site to determine and correct any fertilizer deficiencies or pH corrections needed. Work the soil to 4-6 inches, incorporating the fertilizer or other soil amendments. Avoid overtilling or tilling wet soil which can damage soil structure. Allow time for the soil to settle after tilling to prevent undulations and difficult mowing in the future. Rake the area to the finish grade just prior to seeding. Then apply a "starter fertilizer" to enhance seed germination and development. Starter fertilizer is high in phosphorus (the second number in the analysis on the fertilizer bag). For instance, a 16-22-8 fertilizer contains 22% P₂O₅.

Apply the fertilizer according to the label at 1.5 lb. P2O5/1000 ft².

Seeding

Seed should be applied using a drop spreader if possible because rotary spreaders do not disperse the seed as uniformly. There are no spreader calibration guides for turfgrass seed. The easiest way is to set the spreader adjustment very low, sow one half of the seed in one direction, and then sow the other half at right angles to the first direction of seeding. It may take several passes over your lawn. Seeding rate recommendations are presented below.

After the starter fertilizer and seed have been applied, the area should receive a light raking followed by a light rolling to insure good seed-soil contact. A roller designed to be filled with water, but left empty so it will not compact the soil, is perfect for this job. Maximize the seed-soil contact is critical for quick germination and establishment.

Mulching

Mulching the area will prevent erosion and conserve water. Mulching is most important when it is impossible to adequately irrigate newly seeded areas. One bale of clean (weed-free) straw per thousand square feet will give about the right amount of covering. Many homeowners apply too much mulch which can shade seedlings and have to be raked off later. Apply the straw so you can still see approximately 50% of the soil through the mulch layer.

Watering

Seedlings are very susceptible to desiccation, and the seedbed should not be allowed to dry. A newly seeded lawn will need to be irrigated two to four times daily depending on the weather. Apply enough water to moisten the top one to two inches of the soil, but avoid saturating the area. Once the grass is two inches high, gradually reduce the frequency of irrigation and water more deeply. After the turf has been mowed two or three times, deep and less frequent irrigation is most effective.

Mowing

Mowing a new lawn will encourage the turf to fill in quickly. Mowing should begin when the first few seedlings are tall enough to mow. You may only mow 10% of the plants in the first mowing, 20-30% of the plants in the second mowing, and so on. Most wait too long to mow a newly seeded lawn, so mow early and often. Initially mow Kentucky bluegrass, perennial rye, and fine fescue at 1.5 inches and tall fescue at 2.0 inches. After the first three to four mowings, you can adjust your mower to the permanent mowing height which is 2.5 - 3.5 inches for Kentucky bluegrass, perennial rye, and fine fescue and 3.0 - 4.0 inches for tall fescue. As always, never remove more than 1/3 of the grass blade at any one mowing.

Fertility

New seedlings have poorly developed root systems and thus they cannot effectively absorb nutrients from the soil. Therefore, it is important to fertilize after seeding to encourage establishment. Apply 0.75 to 1.0 lb N/1000 ft² at four to six weeks after germination and again at eight to ten weeks after germination. If seeding in mid-August, these applications would be mid to late September and again mid to late October.

Weed Control Fertility

There is little weed pressure in the fall so weed control may not be needed. If broadleaf weeds become a problem in the fall, they can be easily controlled with a broadleaf herbicide application in October or November, after the third or fourth mowing. Annual grasses such as crabgrass can be controlled with preemergence herbicides applied in the spring. For seedings made very late in the fall where the lawn is not fully established by winter, do not apply a preemergence herbicide early the next spring because it may damage late-developing seedlings. Instead, use a postemergence crabgrass herbicide later in summer.

Spring Seeding

The best time to seed a lawn is in the late summer/early fall (mid-August to mid-September). Seeding in spring is very difficult and often unsuccessful. However, there are circumstances that warrant a spring seeding:

• Thin turf due to winter damage
• Poor turf density due to poor recovery from previous year's problems, i.e., grub damage, drought damage, etc.

To make your spring seeding most successful, you must:

• Seed as early in the spring as possible to maximize the competition of turfgrass over crabgrass. Dormant seeding or early April seeding is preferred.
• Maximize seed-soil contact through good soil preparation.
• Irrigate often as soon as temperatures favor germination (soil temperatures above 55°F). As root systems develop, gradually reduce frequency but increase duration of irrigation. Continue irrigation throughout the summer until an adequate root system is established.
• Control weeds in the lawn because spring germinating weeds will outcompete the desirable turfgrass and may kill the turfgrass.

Dormant Seeding

If a spring seeding is necessary, consider doing it before the frost comes out of the ground. This is defined as "dormant seeding" because the seed will lie dormant until the soil temperatures warm in April or May. Depending on your location, dormant seeding can be done as early as Thanksgiving and as late as March. The benefit of dormant seeding is that as the soil heaves and cracks during the winter, crevices are created for the seeds which create ideal germination conditions. Additionally, dormant seeding is easier to schedule than spring seeding, because spring rains make it difficult to seed.

Weed Control Guidelines

• Perennial grassy weeds (nimblewill, creeping bentgrass, etc.) are not effectively controlled in the spring with glyphosate (Roundup or Kleen Up). Plan this type of renovation for the late summer.
• Avoid using broadleaf herbicides in newly-seeded areas until the new seedlings have been mowed at least three times.
• Avoid using preemergent crabgrass controls (except those containing siduron) at the same time as a spring seeding. As a general recommendation, delay the use of these materials until the new seedlings have been mowed four to eight times, depending on the herbicide. Check the label of the specific crabgrass control material for the exact recommendations. As mentioned earlier, siduron is an exception to this rule. It can be used at the time of seeding, but will only control crabgrass for 3 or 4 weeks.

Seeding into an Existing Lawn

• Mow the area to 1 or 1.5 inches to reduce competition from established grasses.
• Apply a starter fertilizer (high in phosphorus) over the entire lawn at 1.5 lbs P₂O₅/1000 ft².
• Aerify the area punching at least 20 to 40 holes/ft² with the largest tines possible. This will increase the seed-soil contact and improve germination and establishment rate. You can never over-aerify at this time, so make many passes over the lawn. A power raking at this time will also help to increase the seed-soil contact.

Seeding a New Lawn - Summary

• On uncompacted soils with no thatch, an aerifier can be used to expose the soil like previously mentioned. A powerrake set to cut 1/8 to 1/4 inch into the soil also will work well. Follow this with a power overseeder or drop seeding.
• On compacted soils, till the soil to 4 inches or more, rake smooth, allow it to settle for a week or two with irrigation or a heavy rain fall, rake to the final finish, and then drop seed.
• On lawns with significant thatch, a power rake should be used to loosen and remove as much of the thatch as possible. If the thatch is over 1 inch thick, either use a sod cutter to remove the thatch, or till the soil turning under the thatch. Follow this with drop seeding or power overseeding.
• Just before seeding, apply a starter fertilizer (high in phosphorus) over the entire lawn at 1.5 lbs P₂O₅/1000 ft².
• After seeding, roll the lawn with a light roller to insure seed-soil contact.
• Water the newly seeded area three to four times daily to encourage germination after soil temperatures reach 55°F.
• Mow as soon as Kentucky bluegrass, perennial rye, or fine fescue reach 1.5 inches and when tall fescue reaches 2.0 inches. After the first three to four mowings, adjust the mower to the permanent mowing height.
• Six weeks after germination, apply 0.75 lb N/1000 ft² with a fertilizer containing N, P, and K.

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