Thursday, November 27, 2003
Copyright © Las Vegas Review-Journal

GARDENING: Save on mowing by fertilizing lawns in late fall

More and more research points to late fall as the time to fertilize lawns. Most of us don't want to hear that because we're afraid fertilizing means mowing all winter.

Yet when the weather warms up next spring, we eagerly head out and feed our lawns. After all, that is tradition. Early spring feeding triggers top growth and that means chasing the mower across the turf more often. You may even feel like you are producing hay rather than manicuring turf.

Professionals have been preaching fall fertilizing and research by Ohio State University backs them up. The research finds late fall fertilizing:

• Improves quality of turf.

• Increases root growth.

• Improves color through the winter and into spring.

• Improves drought tolerance.

• Decreases spring mowings.

• Decreases summer stress problems.

• Improves weed control.

Research also finds that as temperatures dip into the 50s, top growth stops growing -- which means less mowing -- but it continues to manufacture food to store in the roots for next spring's growth. Therefore, the massive root system can then keep up with the grass blades at an accelerated rate. You have a lawn with all the gusto needed to carry turf into summer and it will be thicker and a richer green. And you won't have to feed the lawn next spring.

Researchers find that lawns lacking nitrogen going into the winter are starving by spring. When you finally add the fertilizer, the turf responds like a hungry hog and nutrients all go to top growth (more mowing). The added top growth saps the roots' stored energy and becomes stressed as you head into summer with no reserves. The turf then loses its ability to recover from disease, insects, drought and foot traffic.

Conversely, feeding now when the turf is slowing down builds a larger carbohydrate pool and the stored nutrients gradually release to the turf as it heads into next spring and summer. You come out of it as the winner, not having to mow as often. As a side note, I've wondered why homeowners have their gardeners mow their lawns every week through the winter. There is nothing to mow.

Another advantage to fall feeding is weed control. A thick, healthy lawn is the best form of weed control. This will reduce the amount of sunlight hitting the soil surface so weed seeds can't germinate. But you must fill in the bare spots or weed seeds will oblige you and fill in for you next spring.

Your nursery has a good selection of lawn fertilizers to select from. Follow the directions for amounts to add. To avoid a striped, unevenly colored lawn, apply the fertilizer in two directions, one half in a north-south direction and the other in an east-west direction. Follow the feeding with a good drink of water to move the nutrients to the rooted area. Now note this, by feeding this fall, your lawn will be able to get by on smaller amounts through the rest of the season and still maintain an acceptable quality of turf.

We are hearing more about the benefits of potassium. Soil tests indicate our soils have ample potassium. Note what it does: builds in cold resistance; makes the green stuff greener; improves the transfer of nutrients through the plant; and improves its stress tolerance to drought, insects, diseases and foot traffic. You'll find potassium already in your fertilizer.

Q: How can I get rid of spotted spurge and crab grass now?

A: The only thing I know of that will take these weeds out now is 2, 10 plus S herbicide. That is getting on two knees and using 10 fingers and some sweat to dig or pull them out before they drop this year's seed cop. Next February apply a preemergent herbicide to prevent seeds from germinating.

Q: I put down crab-grass killer last spring and am wondering why it didn't do a thing?

A: If you had thatch, it absorbed the chemical. Therefore, get rid of the thatch. Second, most gardeners apply the herbicide too late. Apply it in late February. Finally, do not disturb the soil after applying the chemical as it forms a protective layer that prevents weeds from germinating.

Q: Can I keep green grass on one-day-a-week waterings?

A: Yes! After watering your grass, dig down to see how far water soaked into the ground. Ideally you hope the water soaked about 5 inches in the ground. You may have to set your clock to cycle again if it isn't very deep. Have faith in your soil. It is like a sponge soaking water for your roots to use as needed. Keep an eye on your lawn, if it has a droughty look, add more water.

Q: What time of day is it best to water the lawn during the winter?

A: We recommend watering after 9 a.m. If it is real cold the misting water quickly freezes on sidewalks causing a dangerous situation that may hurt someone.

Q: Last weekend we had a little frost on our lawn and someone walked across it. Now the grass looks dead where he walked. Will it come back?

A: Yes! Avoid walking across your lawn when it is frozen or it does brown out.

Q: We are planning to convert to a "Water Smart" landscape. Is it too late to do plants now?

A: I'll say not unless planting frost-sensitive plants. Planting now enables your plants to develop a stronger root system for the hot weather next summer.

Q: We miss the fall colors back East. What are some colorful plants to get that autumn feeling?

A: Here are a few to consider: Virginia creeper, Mexican buckeye, red oak, hackberry, pomegranate, nandina, ornamental pear, Chinese tallow and pistachio, ray wood and Modesto ash, sumac, honey locust and Eastern redbud. These plants are at the Desert Demonstration Gardens so come see them.

Q: When do I fertilize my fruit trees?

A: Wait until they drop their leaves. Adding nutrients while leaves are still on trees can cause spurts of new growth leaving them vulnerable to upcoming frosts. Let trees go dormant before feeding them. Do it around the first of the year.

Linn Mills writes a garden column each Thursday. You can reach him at lmills@reviewjournal.com or at the Desert Demonstration Gardens at 822-8325.