Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I renovate my cool-season lawn?

Renovation takes an existing lawn and establishes new turf from seed without removing the old sod by tilling or grading. For cool-season lawns such as Kentucky bluegrass, perennial ryegrass and fescues, the end of August to mid-October is an ideal time to renovate. There are no short cuts to establishing a high quality turf, so do not skimp on soil bed preparation. Remember, the basic principle for successful turfgrass renovation is to achieve contact between the moist soil and the seeds.

First, the eradication of undesirable species or weeds is necessary. This can be done with several herbicides. For instance, glyph0sate works well. The packaging on this product also gives some good advice on how to renovate your lawn. Pay close attention to warnings about wind drift, dusty conditions and drought conditions. Adequate watering a week or so ahead of time up to the day of spraying can insure positive results. Wait until the areas you have sprayed start to turn yellow before you proceed with the following steps.

If you do not have a weedy lawn, you can start at this step. Yes, you knew it was coming, the thatch word. Most verticut machines or power rakes are effective in the reduction of thatch. They are efficient in removing any of the dead undesirable species or weeds you may have sprayed. If you have an eighth inch or less, of thatch don't worry about it. If you are in doubt, take a sample to a professional for a recommendation. Some thatch is absolutely essential to a healthy lawn.

The next step is to roughen the turf by aeration or grooving. This can be accomplished with the use of an aerator or in the case of grooving you can use a power rake. The intent here is to provide openings in the soil to maximize the soil to seed contact. The biggest problem is not running the equipment over the area enough. Anywhere from-two-to-five passes may be required. Remember that the seed needs to be only barely covered with soil. Deeper is not better.

This next step can be taken at almost any time. Have your soil tested and do what is recommended! Take samples from a number of areas, but concentrate on the problem areas. A plug four-to-five inches deep is excellent because it also shows layers. Try going another six inches in the bad areas, to see if there is a surprise, like rocks or rubble. Soil testing can be done through the Garden's William T. Kemper Center for Home Gardening. See “How do I test my soil?”

Seed selection is very important. Select a mixture recommended for your area and do purchase quality seed. Consult a knowledgeable garden center as to what specific types might be best for your particular purpose. Seed at the recommended rate listed on the package for over seeding. For a currently fairly dense lawn, use the lower rate. For a very thin sparse lawn, use the higher rate. Skimping on seed or exceeding the recommended rates can result in a poor stand of grass.

Planting extra seed will not solve the problem. Lawn renovation is a compromise form of seed bed preparation. Too much seed can encourage disease from overcrowding.

Roll or rake the area to insure good contact between soil and seed. Irrigate the area to the depth of the existing root system. You may need to water more than once a day to keep the top of the soil damp so the seed will not dry out. Water religiously for 10 days to 2 weeks until the grass germinates. Gradually cut back until you are watering only once or twice a week.

Once re-established, consult our Kemper Factsheet on "Lawn Maintenance" for information on the care of your renovated lawn.