Establishing a New Lawn to Achieve Sustainability

In this part of the country, there are two primary means of establishing a new lawn: seeding or sodding. Either can result in a healthy, good quality lawn that will be sustainable once established. The most important difference between seeding and sodding is the time necessary for developing a mature and durable turf. Sodding is essentially transplanting a mature turf that has been cared for by a professional. Seeding involves the same process used in the establishment of sod and can be accomplished by a professional or the homeowner. The number of variables involved in seeding make it difficult and many times unsuccessful for homeowners. Table 1 lists advantages and disadvantages of each establishment method.

Table 1. Seeding and Sodding comparison
Seeding

More grass types and varieties to choose from
Less expensive than sodding
Stronger root system development initially

Disadvantages
Initial establishment is longer
For best results, time of seeding is limited mainly to late summer and early fall
Moisture is critical for the young seedlings

Sodding

Rapid establishment and relatively weed-free in the beginning
Good for slopes or areas prone to erosion
Can be laid any time during the growing season

Disadvantages
Expensive
Less selection or control over kinds of grasses, especially shade or drought tolerance
Not adapted for use in low-maintenance situations

Sometimes the best approach to lawn establishment is a combination of the two methods. This can help reduce costs and meet specific site needs with the use of the most appropriate method. The latter point is key to establishing a sustainable lawn as the best-adapted plants are established in the right place.

Proper Soil Preparation

Regardless of which method you choose, success will depend on good soil preparation. If this step is done properly, the lawn will give you years of satisfaction. If you neglect this step or try to economize too much, it will be more costly to correct the problems you may encounter after the lawn is installed.

Guidelines to Avoid Common Pitfalls During Soil Preparation* Remove existing perennial broadleaf weeds and grasses. Examples of broadleaf weeds include: dandelions, thistles, plantain, and clover. Examples of perennial weedy grasses include quackgrass and orchardgrass. Leaving existing weeds and grasses only invites weed problems in the newly establishing lawn.* Test the soil and add the necessary potassium or phosphorus by rototilling it into the top 4 to 6 inches. Don't assume the topsoil you add is rich in nutrients, regardless of its color. Test it and make any nutrient additions that are necessary. Topsoil should be of a sandy loam texture with a good black color. Avoid heavy muck soils sometimes offered as topsoil.* If you add topsoil or peat, rototill it into the upper 4 to 6 inches. This step can be combined with the fertilizing step just described. For sandy or clay-like soil, spread 12 to 18 cubic feet of baled peat per 1,000 square feet. However, it should be noted that sandy soils are excellent for growing grass without the need for peat additions IF consistent irrigation can be supplied. If you are adding topsoil, apply it at a rate of 3 to 4 cubic yards per 1,000 square feet.* Don't let anyone talk you out of proper soil preparation if you are adding topsoil or peat. Leveling with a grader blade is not a substitute for rototilling. Rototilling under trees will disrupt their feeder roots and may cause considerable damage. Using a vertical mower to simply scratch the soil surface when you prepare the area beneath trees would be a better method of soil preparation.

* Don't pack the soil too firmly before seeding or sodding; use a garden rake to level uneven areas.

Establishment by Seed

In the upper Midwest, Kentucky bluegrass, fine fescue, and some of the perennial ryegrass cultivars are recommended. However, before a seed mix is chosen, evaluate the location: Is there shade, excessive use or wear, etc.? Is the desired lawn to be a showcase and green throughout the season (high maintenance), or is a healthy turf with a minimum of fuss (low maintenance) preferred? These are important questions to consider when choosing grasses.

* A Kentucky bluegrass blend containing at least two or three varieties is a good choice for sunny lawns. The benefits of a blend is that each variety may be different in its resistance to various disease and environmental tolerances, such as drought and shade.* Some turf-type perennial ryegrasses have been used in home lawns for durability and foot traffic tolerance. To grow well, many perennial ryegrasses require more fertilizer and water than do the Kentucky bluegrass/fine-leaf fescue lawns.* Fine-leaved fescues are often mixed with Kentucky bluegrass in areas that have more shade. For theses areas, use a mix consisting of 60 percent fine-leaved fescues and 40 percent Kentucky bluegrass varieties. Fine-leaved fescues can also be added to a bluegrass mix to lend drought tolerance in a sunnier location.* For low maintenance turf, mixtures of common Kentucky bluegrass varieties and fine fescues will offer a durable lawn.

* No more than 5 percent to 10 percent of any grass seed mix should be made of Italian or annual ryegrass. These plants are annuals and will not come back after the first winter. Also, due to their rapid germination and early seedling growth, they can overpower the more desirable lawn grasses that take a longer time to germinate, grow and become established.

The availability of specific varieties will vary from year to year; however, within a particular kind of grass (e.g., fine fescue or improved Kentucky bluegrass), most varieties will perform equally well. Your local seed distributor, garden center, or county extension educator can help you evaluate the best varieties for your lawn. Some varieties can be special ordered, but usually at a higher cost.For a complete discussion regarding the adaptability of lawn grasses to our area and to specific site conditions, see the section titled: Cool Season Grass Selection for a Sustainable Lawn.TimingThe best time to seed in Minnesota is late summer (mid-August to mid-September) due to favorable conditions for germination and growth. In addition, fewer weed seeds are germinating that might compete with the grass seedlings. Lastly, there is ample time for the plants to be well established before winter. Seeding can also be done in early spring. However, weeds and high summer temperatures often reduce the chance of success. Most annual weeds that compete with new grass seedlings germinate in spring. Only the selective preemergent herbicide Siduron, (trade name Tupersan), may be used on newly seeded lawns. It will help reduce problems with crabgrass competition while the newly seeded area is getting established. In addition, the short growth period in spring allows less time to develop a root system to survive the summer heat stresses.Germination among the different cool season lawn grasses is quite variable. For example, Kentucky bluegrasses can take 14 to 28 days to germinate while perennial ryegrasses will germinate in as little as 5 to 7 days. The fine-leaved fescues generally require 14 to 21 days to germinate. Thus, perennial ryegrass, like annual ryegrass, can seriously compete with the Kentucky bluegrasses and fine-leaved fescues. This can significantly reduce the amount of these two types of grasses in the established lawn. It should be noted that summer germination times are usually those toward the lower end due to warmer soil temperatures while the longer times are more typical of spring sowings.

Dormant seeding involves sowing the seed after cold weather has set in, but the ground is not yet frozen solid. Usually this is sometime in early to mid-November. The principle is that the seed will remain "dormant" due to the cold soil conditions, but begin to germinate as soon as the soils start to warm in the spring. This avoids having to prepare the soil when it is still wet and cold in the spring and can result in several weeks head start in getting the lawn established. This method generally works best when the newly seeded areas are covered with several inches of snow soon after seeding that remain in place over the entire winter period. Open winters with extended warm periods followed by extremely cold periods can be disastrous for dormant seeded lawns.Purchasing Seed

Purchasing the highest quality seed possible is always a good investment. Poor establishment resulting from improper cultural practices will negate the monetary investment in purchasing high quality seed. However, poor quality seed will almost never result in a well-established lawn no matter how good the cultural practices. Determining what is high quality seed can be difficult for most people. Purchasing high quality seed can be easier by understanding a few basic terms on the grass seed label. See Fig. 1 for an example seed label. All labels must provide information about the grass seed purity, its germination potential, crop seeds present, weed seeds present, noxious weeds present and inert components in the package.

Figure 1. Example Seed Label (company and variety names are fictitious) WILL-GROW SEED COMPANY TURFTOWN, OREGON Lot No: 1234-B Test Date: month/year
Pure Seed	Variety	Germination
44%	Arctic Creeping Red Fescue	85%
31%	Blue Ribbon Kentucky Bluegrass	80%
9%	Wilson Chewings Fescue	85%
12%	Gopher Perennial Ryegrass	90%
1.56%	Crop
2.11%	Inert Matter
0.33%	Weeds
Noxious Weed Seed:25 Canadian Thistle Seeds Per Pound

Purity is the percent by weight of pure seed, crop, weed, and inert ingredients in the package. These percentages added together should total 100 percent. Purity is concerned only with quantity, not quality. That is, not all seeds present in the package are capable of growing. To determine the seed that will actually grow or what is known as pure live seed, the percentage purity should be multiplied by the germination percentage. For example, 90 percent Kentucky bluegrass (purity) multiplied by a germination percentage of 85 percent equals 76.5 percent. This is the percentage of Kentucky bluegrass that one would expect to grow under optimum germination conditions. It should be apparent that one would always seek to purchase the grass seed with the highest purity and germination percentage possible. Germination is the percent of pure seed that will germinate and grow in an ideal laboratory environment during a prescribed length of time. Since field conditions rarely ever duplicate these laboratory conditions, it is especially important to purchase seed with the highest germination percentage possible. As noted above, this is the percentage used to determine pure live seed. Crop is the percent by weight of seeds normally considered to be grown as an agricultural crop, including hay. This can include other types of grasses that may be undesirable in a lawn situation. This percentage should be as close to zero as possible. Weeds refers to the percent by weight of all seeds in the package that are not otherwise listed in pure seed or crop. It is not required to identify these weeds or how many there are since this is on a percent by weight basis. For example, 1 or 2 large seeds of a weed would pose no particular threat to the new lawn. However, some tiny seeds that weigh very little, such as chickweed, can account for many thousands of weed seeds distributed over a 1000 ft² of lawn area. This percentage should always be as low as possible. Noxious weeds are listed as the number per pound not as percentage per pound. Noxious weeds are weedy plants considered by individual states to be very difficult to control and could pose hazards to both humans and livestock. While this is often more of a problem in farm crop seed, one should always purchase grass seed without the contamination of any noxious weeds.Inert is the percent of material contained in the package that will not grow under any condition. Broken and damaged seeds, chaff, and empty seed hulls are just some of the more common inert material included. Obviously, this percentage should be as low as possible.Considering Seed Count vs. Seed Weight.

The Federal Seed Act requires that grass seed be listed on the label by weight and that it be separated into two broad categories: fine-textured grasses and coarse-textured grasses. However many of the grasses vary significantly in their respective seed sizes and consequently vary significantly in the number of seeds per pound. A more accurate description of the grass seed contents contained in a package would be to list their percentage by seed count rather than percentage by weight. For example, large seeds (such as those of perennial ryegrass) are quite heavy and take only about 225,000 seeds to make one pound. On the other hand, Kentucky bluegrass is much smaller and therefore a much lighter seed by weight than perennial ryegrass. In fact, Kentucky bluegrass requires from 1 to 2 million seeds depending on variety to make a pound. Table 2 contains the number of seeds per pound for several other common lawn grasses.

Table 2. Some ranges for the number of seeds per pound for several cool-season lawn grasses
Creeping bentgrass	5-8 million
Kentucky bluegrass	1-2 million
Fine-leaved fescue	400 to 500 thousand
Perennial ryegrass	200 to 225 thousand

Given the above example, a 50 percent perennial ryegrass : 50 percent Kentucky bluegrass mix by weight actually contains only about 112,500 seeds of perennial ryegrass per pound of mix. The number of Kentucky bluegrass seeds present in this same mix would be about 500,000 to 1 million. Therefore the percentage of perennial ryegrass : Kentucky bluegrass contained in this sample mixture based on seed count is about 11 to 23 percent perennial ryegrass and 77 to 89 percent Kentucky bluegrass. Using this example, one may need to add a certain amount of one type of grass or another based on seed count to create the best mix for a particular site condition. For example, adding some additional pure creeping red fescue seed to an "off-the-shelf" seed mixture for shady areas will increase the number of seeds of the more shade tolerant creeping red fescue. This should provide greater potential for establishing a lawn area in the more shady parts of the landscape. For more about purchasing grass seed, see:

Seeding Rates and Planting Methods

Seed Kentucky bluegrass blends (i.e., a combination of several Kentucky bluegrass varieties) at a rate of 2 to 3 pounds per 1,000 square feet. Use 3 to 4 pounds per 1,000 square feet when the seed mix contains Kentucky bluegrass and fine-leaved fescues. Using too much seed will result in higher costs and slower establishment due to competition between grass plants. Using a rate that is too low will prolong the time it takes for the grass to completely cover the soil surface and allow more opportunity for significant weed invasion to occur. See Table 3 for examples of different seeding rates for different blends and mixtures of turfgrasses.

Table 3. Commonly Used Seeding Rates Per 1000 Square Feet of Home Lawn Area
Kentucky bluegrass only	2-3 pounds
Kentucky bluegrass/fine fescue mix	3-4 pounds
Kentucky bluegrass/perennial ryegrass mix	3-4 pounds

Hand Seeder Seeding by Hand or Hand-Powered Equipment

Hand seeding is most practical where only small areas are to be established. First, lightly rake the soil surface loosening at least the top 1/2 inch of soil. This will allow for easier incorporation of the seed into the soil surface helping insure good seed-to-soil contact. Next, spread the seed by hand or by using a drop type fertilizer spreader calibrated to deliver the appropriate seeding rate. Whether you use a drop spreader or spread seed by hand, apply half the desired rate in one direction, then spread the second half at a right angle to the first to insure a good pattern of distribution. Follow up with a light raking allowing about 10 to 15 percent of the seed to show. Lightly roll the area to ensure good seed-to-soil contact. Note: Drop spreaders are generally preferred for seeding as they are more accurate due to less influence by windy conditions and differential seed size (i.e., larger seeds are thrown farther than smaller seeds when using a rotary spreader, resulting in uneven distribution of grass species within the area).

Be careful not to bury the seed too deeply. Seed that is buried too deeply may not germinate. Always gauge depth of planting by the smallest seed in the mix. For example, when mixtures of Kentucky bluegrass, perennial ryegrass and fine-leaved fescue are used, depth of planting should be determined by the Kentucky bluegrass seed as it is the smallest of those in the mix. In this example, planting depth for all seeds would be about 1/4 inch for the mixture. This would be the normal recommended planting depth for Kentucky bluegrass. Mechanical Seeder Larger areas are better seeded with mechanical devices that can either be rented or done by a turfgrass professional. A walk-behind machine known as a "slit seeder" can be rented or used by a hired professional. This machine loosens the soil just ahead of a series of discs that cut a groove to a specified depth in the soil. A series of tubes drop down from the seed hopper beside each of the discs. Seeds are dropped through the tubes at a specified rate into the groove and lightly covered by the rotating disc. This allows precise placement of the seed at the proper depth and spacing. Again, it is usually desirable to seed in two directions perpendicular to each using half the seeding rate in each direction. Seeders known as "cultipackers" are commonly used for seeding large sites. These units are tractor mounted and provide very uniform seed distribution while also firming the seedbed after planting. The cultipacker seeder is equipped with a ridged roller component to help ensure the proper seed placement. While seed may germinate somewhat uniformly across the surface, better germination is often observed in the parallel "valleys" made by the ridged roller immediately after seeding. This type of seeding is very efficient for large areas and produces excellent results. Splitting the seed amount in half and going to different directions will help achieve faster establishment.

Once seed is planted, make sure that the soil is kept evenly moist although slight drying between waterings is not detrimental and may even be beneficial. South-facing slopes and other parts of the yard exposed to hot afternoon sun may dry out more rapidly and require additional watering on a more frequent basis.

Water Sprinkler Moisture is critical once seeds start to germinate. They should not be allowed to dry. After the majority of seeds have germinated you can water more heavily, but less frequently, to encourage deeper rooting. Be sure that all of the different grasses contained in a mix have germinated before cutting back on moisture. Establishment should take 6 to 12 weeks. If you seed in late summer (mid-August to mid-September), the lawn should be usable the following spring.Mow the lawn once it reaches a height of 3 inches. Cut no more than one inch off, otherwise you will slow the establishment process. Mowing regularly in this way encourages deep rooting and helps maintain good growth. In addition, where the fast germinating perennial ryegrass is used in the mix, mowing when it reaches 3 inches will help prevent excessive competition with the much slower germinating fine-leaved fescues and Kentucky bluegrass.When seeding in the late summer or early autumn, a preemergent herbicide should not be needed. Weed control using contact herbicides in a newly seeded lawn will have to wait until it's been mowed four times to allow the plants to become well established. Also, many of the troublesome broadleaf weeds that appear during the early establishment period will disappear once a regular mowing schedule has begun. For more on seeding the lawn, see:

Sodding the Lawn

When sodding a lawn, the consumer is limited in the varieties available. Most of the sod grown in the Upper Midwest is a blend of Kentucky bluegrass varieties and, as such, are unsuited to shady conditions although some may tolerate light shade.

NOTE: To insure good results, the same soil preparation must be done to sod a lawn as to seed it. With proper soil preparation and care, both upland and peat sod will perform equally well.

Sodding can be done any time after the ground thaws in spring, right into autumn. The limit on fall sod laying is the amount of time the sod has to develop roots before the ground freezes. The later sod is laid, the more risk that it will suffer damage if there is an "open" winter with poor snow cover.

Purchase sod as fresh as possible. Ideally, it should have been cut no more than 24 hours prior to delivery. The sod should be laid as soon as possible, or within one day after delivery. If the sod needs to be stored for a time, it should be kept in a cool, shaded area, and drying out of exposed rolls avoided.

Suggestions for Successful Sodding

When your sod arrives, have it stacked in the shade to prevent heating. Make sure you keep the outer rolls lightly watered. Complete your sod laying within 24 hours from delivery to minimize heat build up in the sod rolls that can kill the plants. Lay the sod on slightly moistened ground. Stagger sod joints, butting the edges as close together as possible. Lay sod the long way across slopes and peg it down to prevent it from sliding once it is watered. After sod is laid, go over it with a light roller, no more than 1/3 full of water, to insure good sod-to-soil contact. Water sod thoroughly, followed by lighter, frequent watering. Continue to water frequently during the two to three week establishment period, then gradually water less often but more heavily.
Aerification may help prevent soil layering caused by peat or soil that came with the sod. Aerify the spring or fall after establishment. Be sure to aerify deep enough so that the tines penetrate through the sod at least two to three inches into the soil.

Establishing a new lawn from sod or seed can be a very satisfying experience on its own. Once the lawn is established, it will provide many benefits such as cooling, erosion prevention, runoff control and allergen reductions. Having planned and installed a well-designed landscape with appropriate areas devoted to lawn grasses that will meet family needs and be sustainable can be particularly gratifying. For more on establishing a lawn from sod, see: