Vail garden column: Fertilizer 101
January 8, 2014
With good weather back in Colorado, you may have a hankering to get outside and make something happen in the yard. But if fertilizing the lawn is on your mind, think again.
Especially if you applied fertilizer last fall, the lawn should not need another application until mid-May or later. That fall fert is one of the most important applications of the year — so if you did it, good for you and your lawn!
Start with the basics
What is fertilizer supposed to do? According to landscape industry Best Management Practices and the scientists at Colorado State University (CSU), fertilizers are for clearly defined results that include more shoot growth, colorful foliage and plant health.
When should you fertilize the lawn?
• Why not in April: The only reason to apply fertilizer early is if you use the "weed and feed" variety that controls early-season weeds. CSU turf experts caution against over-application of nitrogen in April because it can cause the grass to grow too fast before the roots can support the growth. Pushing grass growth over root growth is counterproductive and will make the lawn less heat tolerant.
• Best times to fertilize: an easy memory tool is to plan around major holidays. Mother's Day to Memorial Day is good timing for the first application. Fertilizing before the 4th of July (mid to late June) is good for the second application. Time the third application around Labor Day and then have the fall application done before Halloween.
• Avoid the hot months. According to CSU, from July through mid-August, fertilization is not required.
How to select fertilizer
• Select slow-release or controlled-release fertilizers and natural organic-based fertilizers (not to be confused with manure). Slow-release cuts the risk of nutrients leaching into ground water or running off in surface water.
• The top three nutrients on the bag are Nitrogen, Phosphorus and Potassium. Nitrogen is the key ingredient, but it works along with the other nutrients. Garden center experts can help you sort out the elements.
• Since manufactured fertilizers are often relatively high in nutrient content, follow the manufacturer's label and apply the minimum amount recommended.
• If you use a mulching mower and leave clippings on top of the lawn, you can use 1/4 to 1/3 less fertilizer.
• Broadcast fertilizer uniformly over the lawn. Selecting a fertilizer with the word "homogenous" on the label means particles are all about the same size and will spread more evenly.
• Fertilize the day before your scheduled watering day so that water can get nutrients soaking into the soil right away and minimize fertilizer "burn."
Becky Garber is member of the Associated Landscape Contractors of Colorado of which Neils Lunceford, a landscaping company, is a member. You may contact them at 970-468-0340.