Thursday, February 21, 2008
Weeding advice for a new lawn
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
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Q: I recently moved to a new house in Botetourt County with a newly planted yard. The builder seeded in October and so far the new grass is about a half inch to an inch tall. The builder brought in topsoil and seeded with fescue. Not all of the yard received topsoil. The rest of the yard is the red clay type. I have about an acre and a half but not all of it is yard. There are a lot of weeds already. The most common is the broadleaf type. I’m guessing buckhorn plantain or broadleaf plantain. The yard used to be a field before they built the house.
I am used to having a very nice yard and enjoy working in the yard and with the landscaping. What do you recommend I do this spring to get the turf started on the right path and how should I combat the existing weeds? I know fall is the best time to seed and fertilize but I know I don’t have the patience to wait until then to start working on the yard. I’m not opposed to starting over if it means a better result in the long run.
A: Let’s start with the weeds. The best time to control weeds is when they are tender. That tenderness time is determined by the weed’s growth classification as either a perennial, which is frequently tender in mid fall in the Roanoke area, or winter annual that is easier to kill in the fall, or summer annual, usually easier to kill in the spring. Unfortunately, though, I don’t know of a good broadleaf weed killer chemical that is mild enough for use on tender new grass. Your new grass seeded by the builder last October could be killed itself by a chemical that is manufactured for use on established grass plants. A good rule of thumb to use says that new grass is tender under it has grown enough for 3 regular mowings.
Weed plants tend to germinate and grow where there are openings in grass cover for them to receive sunlight. Overseeding good grass to increase the healthy turf plants and close those opportunities for weeds to grow in is a good recommendation, but overseeding this spring might not produce permanent grass plants capable of living on their own without watering due to poor root growth in hot soil. Late summer or early fall is the recommended time to overseed.
If the seeding done by your builder last October resulted in a fifty percent or better coverage, I’d recommend that you keep that grass and work this spring to improve its density and appearance rather than starting over with killing the new fescue, working in fertilizer and soil amendments, sowing grass seed, watering faithfully, and hoping.
Buy quality hoses and sprinklers now and make plans to water your new grass sown in October 2007 once or twice per week during dry times of the entire growing season in both your topsoil areas and clay soil areas. Your plan should also contain a contingency plan in the event that outdoor watering becomes limited. Decide on priority areas that should receive water if other areas must be left to nature’s whims.
Try to minimize activities on the new fescue during the entire growing season. Your goal will be to enhance grass root growth by reducing soil compaction.
Begin mowing the new grass when it gets tall enough so that cutting removes no more than one-third of the grass height to maintain 3-inches tall fescue. Sharpen your mower blade now and again after each 10 hours of cutting. This will help to avoid grass blade wounds that require energy to heal. Encourage root growth by mowing often enough so that no more than one-third of the grass height is removed at a time.
