Posted on: Friday, April 22, 2005

HAWAI'I'S GARDENS
Want to create a new lawn? The time to start is right now

By Jay Deputy

This is the best time of year to establish a new lawn. Over the next two weeks, we'll help you get started.

Starting a new lawn is a major investment in both time and money, but it is a permanent enhancement to your property, so it's important to take the time to do it right.

If you think you'll need an irrigation system, now is the time to install it.

The first — and most important — part of the process is to make sure the planting area is properly prepared. Don't take short cuts. Five or six weeks are necessary for the entire preparation to be completed, so don't plan on anything less.

Start by collecting a soil sample and get it analyzed by the College of Tropical Agriculture and Human Resources Diagnostic Service Center at the University of Hawai'i-Manoa (956-6706). It usually takes a few weeks to get the results, so in the meantime, start killing off unwanted old grass and weeds.

Herbicides are more effective when the weeds are healthy and rapidly growing, so apply a turf fertilizer high in nitrogen. Water well every day for a week or so and the weeds and old grass will be ready for the first herbicide application.

Use a nonselective herbicide such as Roundup (it kills everything it contacts, so be careful to follow the directions on the label). Continue to water often; it will take 10 to 14 days to see a complete kill.

You should receive the soil analysis results from UH by the time the first crop of weeds has died down. The soil report will give a recommendation for fertilizer application and possibly a pH (soil acidity) correction.

Apply the recommended amount of fertilizer. This is also a good time to spread several inches of well-composted organic matter over the entire planting area.

One cubic yard of compost will cover 100 square feet to a depth of three inches. You can buy it by the truckload from Hawaiian Earth Products. Roto-till to mix the fertilizer, compost and soil to a depth of at least six inches. Continue to water and let the soil settle for a week. Use a roller if necessary to help settling and level the surface.

Seeds of all types will be exposed by the tilling, producing a new crop of weeds. Let them grow for two weeks and spray with Roundup again.

Repeat the spraying until very few new weeds emerge over the next several weeks. Be patient: A weed-free planting bed will make life much easier in the months to come. This is especially true if you are going to seed your new lawn.

Herbicides should not be used on young grass seedlings until they are 3 to 4 months old, during which time hand-weeding is the only option.

When you are reasonably certain most of the weeds have been eliminated, roll the area once more to firm it up if necessary and then lightly rake it out for final grading.

You are now ready to plant the new grass with some confidence that weed pressure will be at a minimum and the soil conditions will support the long-term health of your lawn.

Next week, we'll look at costs involved in new lawns.

Jay Deputy is an education specialist in landscape horticulture and turf at the UH-Manoa Department of Tropical Plant and Soil Sciences, and state administrator for the Certified Landscape Technician Program sponsored by the Landscape Industry Council of Hawaii. Got a lawncare or turf question? Write to deputy@hawaii.edu.