Lawn Care Essentials: Feeding & Watering

Part two in a three-part series on environmental lawn care

Your lawn should be an asset to both your landscape and your lifestyle. Unfortunately, many homeowners have unwittingly turned their lawns into economic and environmental liabilities through over-fertilizing and over-watering.

Americans apparently feed their lawns the same way they feed themselves: too much and too often. For example, if you are currently preparing to pull out your spreader brimming full of 10-10-10: Stop!

Spring is the wrong time to fertilize most varieties of grass. Feeding your lawn now will simply encourage rapidly growing grass to grow even more vigorously. Moreover, it is likely that much of the quick-release fertilizer you might be using will release itself with the next downpour right off your lawn and into the nearest stormwater inlet.

If you are grasscycling your lawn, allowing clipping to remain behind when you mow, you are actually returning a prodigious amount of nitrogen and other nutrients to your lawn. Why buy “fake” or synthetic fertilizers, possibly manufactured from foreign oil, when you can recycle the real thing for free?

For most cool weather grasses, such as the fescues and Kentucky bluegrass, feeding can be put off until the fall. And before you start loading up on bags of fertilizer, take time to have your soil tested.

An inexpensive, eight-dollar soil test kit, available from your local Cooperative Extension Service, will provide you with complete information on the appropriate type of fertilizer to apply to your specific soil and turf variety, as well as the proper application rate and schedule. It will also include important advice regarding your soil’s pH and potential need for lime application. (Learn more about soil testing by viewing Putting Your Soil to the Test, April 10, 2009.)

In addition, stay clear of quick-release, water-soluble fertilizers that promise fast-greening. These will produce fast foliar growth and do little for root development and overall plant vigor. Instead, consider natural organic sources like compost or composted manure, or select other slow-release fertilizers such as IBDU, sulfur-coated urea, ureaformaldehyde, or methylene urea.

Well-intentioned homeowners often water their lawns improperly and at great cost. Consider that during midsummer, it can easily take 6,000 gallons of water per week to keep a typical quarter-acre lawn green and lush -- enough to fill a good-sized swimming pool once every month.

Common mistakes include watering by hand or relying on light, frequent water applications. This approach encourages roots to reach up to the soil surface for moisture, which is one of the most common causes of thatch. Moreover, these shallow root systems make lawns sensitive to temperature extremes, drought, and soil compaction. Frequent watering also encourages the germination of troublesome weed seeds.

Over-watering is much like over-fertilizing. An abundance of water results in faster, excessive leaf growth, which depletes a lawn's natural energy reserves and weakens its disease resistance. The artificially high moisture and surface humidity conditions are also ideal for the growth and spread of disease pathogens.

Over-watering can also waterlog your soil, leading to reduced soil aeration, as well as soil compaction and problems injurious to the plant's roots.

For the healthiest possible lawn, water only when absolutely necessary, such as when grass starts to experience drought stress, usually indicated by the lawn losing color or becoming dull, or when grass fails to straighten up after being walked upon. Of course, during a prolonged drought, such as last year’s, it is probably easier to simply let your lawn go dormant until rain and cooler weather return.

For newly established turf areas, make sure that moisture soaks into the soil sufficiently to moisten the root zone. You can easily check water penetration by simply inserting a screwdriver.

During hot, dry weather, your lawn may require up to one inch of water every five to seven days. To irrigate properly, try to water only during the morning, as midday watering can lead to scalding and wasteful evaporation, while late-day or nighttime watering invites disease.

Apply approximately one inch of water to each area of your lawn and overlap the watering patterns. To ensure adequate coverage, set up one of more inch-high containers under the path of the sprinkler to measure application. Empty tuna fish cans are perfect gauges.

Stop watering whenever runoff occurs, especially on slopes or on compacted, dry soils. That may mean turning the water on and off in cycles to allow moisture to soak into the ground. It may take a bit more time, but it is better than watching water run into a stormdrain.

And finally, stay off your grass while the lawn is wet. Wet soil is easily compacted, which provides an ideal environment for many stubborn weeds. In addition, walking on wet grass can potentially spread fungal spores and other disease organisms.

Copyright 2009, Joseph M. Keyser