Renovating a Home Lawn
There are many reasons why homeowners may need to renovate their lawns. Maybe the aesthetic quality you desire from your lawn cannot be achieved with the present grass type that had existed "for all those years." Some of you may have had the unpleasant experience of having a lawn seriously injured by a fungus disease or an insect pest. Maybe you are a new homeowner and the previous owner neglected the lawn and has left you a plot containing every imaginable weed known to invade a lawn. Lawn renovation is a way to upgrade your lawn from some of these present conditions.
Renovating lawns today can give very favorable results compared to years ago. This is due to the availability of numerous improved turfgrass cultivars developed over the years to look good, with less maintenance and at the same time resist things like disease and drought. Also the machinery available to renovate lawns today eliminates the need to "turn-under" an existing lawn before you seed. This eliminates the need for raking, re-grading, etc.
First determine the reasons why you are considering lawn renovation and find out if upgrading can be accomplished by following proper lawn maintenance procedures. For those fitting into this category you probably don't have to read any further.
If the lawn has deteriorated beyond what normal maintenance can solve, then renovation may be the answer. First determine why the lawn has deteriorated into its present condition.
Common problems experienced by homeowners on Long Island are poor drainage, thatch, compaction, excessive shade, the wrong grass type for your maintenance and/or site, disease, insects or other factors. Problems of this nature can usually be rectified by a combination of renovation and proper maintenance thereafter. One factor that makes lawn renovation unsuccessful is a thatch layer of 1-1/2 inches or more. If this is the case the lawn may need to be started over from "scratch" either by removing the existing turf with a sod cutter or by turning under with a rototiller.
Now have the soil tested.
It is imperative to correct soil pH and nutrient problems. Plan ahead since it takes a couple of weeks to receive results. Limestone, if needed, should be applied at least 3-4 weeks before or after fertilizing. You should plan on seeding in late summer/early fall (mid-August through September).
In most seasons on Long Island you will find that the air temperatures have cooled, but the soil temperatures are still warm enough for seed germination. This, accompanied by adequate rainfall, makes for a very favorable environment for lawn renovation.
Maybe you will be the lucky one and only need to renovate your lawn partially. Lawns in this category are those containing at least 50 percent of desirable permanent grasses, they have no other noxious perennial grasses, and if thatch is present it does not exceed 1-1/2 inches. You will need to identify the weeds that presently occupy areas of your lawn.
In order to eliminate the competition these weeds present, a suitable herbicide would then need to be applied. You can use one of the selective broadleaf herbicides used to control most of the common weeds found in a home lawn. A selective herbicide will kill the weeds but at the same time not injure the desirable turfgrass. You will have to wait between 2 to 4 weeks (depending on the ingredients contained in the product) after applying these herbicides before you can apply new grass seed. Refer to individual product labels for specific recommendations. If thatch is a problem it should be removed now.
Lawns that were made up of grass types other than Kentucky bluegrass may not require this step. Power rakes or de-thatching machines can be rented to eliminate thatch layers. Run the machine over the lawn in at least 4 directions (including diagonally). It is necessary to rake off the debris resulting from the de-thatching process. It is very important to make sure that the seed you are going to apply is in direct contact with soil.
Good seed to soil contact will insure optimum germination.
Research at Cornell University has found that the following step-by-step procedure provided the best results in allowing optimum seed germination and establishment of the new turfgrass:
When selecting a turfgrass seed mixture choose a high quality seed dominated by the turf type which will provide you with the desired aesthetics and maintenance level as well as tolerate the conditions of your particular site, i.e. shade. A disk type seeder is used by some to apply seed to areas requiring renovation.
- Suppress the growth of the existing lawn grasses. Scalping the lawn by mowing it very short will do this.
- Aerate the soil by using a hollow tine core aerating machine. The machine should have hollow tines that should be able to remove cores about 6 inches deep. Go over the area to be renovated in two directions that are at right angles with each other.
- Let the cores that are removed dry out and then break them up and drag them to fill in the holes that resulted from the aerating process. A steel "drag mat" will work best for this procedure.
- Spread the grass seed which you have selected.
- Apply a starter fertilizer. These fertilizers are usually in a 3-4-1 or similar ratio. An example is 18-24-6. Your soil test results may indicate the need for a different analysis fertilizer.
- Drag (lightly) the fertilizer and seed into the soil layer created by the core aeration.
- Roll (lightly) the fertilizer and seed to achieve seed to soil contact. Do not bury the seed deeply.
- Water the newly seeded area concentrating on keeping the soil moist throughout the seed germination period. Perennial ryegrass will germinate under optimum conditions in 7-10 days where Kentucky bluegrass will take approximately 3 weeks to germinate.
- Three weeks after the grass seed has germinated apply a regular turfgrass fertilizer.
- Set your lawn mower blade height at 2 inches and do not let the grass exceed 3 inches in height (never remove more than 1/3 of the grass blade at any one mowing).
This type of seeder has a series of stationary knives which cut grooves in the soil. The grooves are cut to the proper depth for seeding (approximately 1/8" into the soil). At the same time seed drops down tubes from a seed-hopper located on the machine and is placed in the mineral soil under the thatch. Finally the grooves are covered with soil by a series of disks located in the rear of the machine. Seeding should be done in several directions including diagonally to insure good coverage.
It is also important to be sure the soil is not too moist. Moist soil can make the disks moist and the seed may stick to the disks. This may cause a uneven distribution of seed in the grooves.
Some individuals also use a verti-cutting machine. This machine will only cut grooves in the soil. You then would follow up by spreading the seed in two directions with a drop-type or broadcast spreader. The area would then be dragged to pull and/or work the seed into the grooves or seedbed.
For those of you with lawns containing less than 50 percent of a desirable turf type, it will be necessary to follow steps for a complete or total renovation.
This treatment provides no residual weed control.
- To kill all grass and growing weeds, omit at least one mowing before spraying.
- Apply glyphosate (Roundup) at the rate required for specific weeds and/or grass. Be sure to achieve thorough spray coverage of all existing grasses, weeds, etc., in the existing lawn. Do not contact foliage of desirable plants.
- Allow 7 days before seeding.
Do not use glyphosate in galvanized or unlined steel sprayers.
After the weeds and undesirable grasses have been killed, you will follow the step-by-step process for establishing a seed bed which is described under Partial Renovation above.
Pesticide recommendations obtained from 2001 Pest Management Recommendations for Commercial Turfgrass, Cornell Cooperative Extension publications. It is strongly recommended that you refer to a copy of these publications for more information on pest control.
This publication contains pesticide recommendations. Changes in pesticide regulations occur constantly and human errors are still possible. Some materials mentioned may no longer be available, and some uses may no longer be legal.
Read the label before applying any pesticide.
Original Prepared by: Thomas Kowalsick, Horticulture Consultant, Cornell Cooperative Extension - Suffolk County;
Information obtained from: Lawn Renovation in New York State by Norman W. Hummel, Jr., Extension Turfgrass Specialist, Cornell University, 12/6/88 and Cornell Turfgrass Short Course 1999.