Understanding Lawn Fertilizers

Understanding Lawn Fertilizers

Your particular gardening habits will probably dictate when and how often you fertilize your lawn and which type of fertilizer you choose.  Another factor you should consider is the importance you place on your lawn’s appearance.  Do you want a deep green, well-manicured lawn, or a rough-and-tumble grassy surface for a good game of football or croquet?

One good rule of thumb for timing fertilizer applications is to fertilize lawn grasses when their rate of growth slows down and the deep green color fades to a yellowish shade.  Other gardeners may prefer to fertilize by the calendar—once a month during the growing season.  Take a good look at the wide range of fertilizer products available and their diverse methods of treatments and application; you should find a product that will meet your particular gardening habits and your lawns needs.

Choosing a Lawn Fertilizer

Providing a sufficient nitrogen on a regular basis is the key to healthy looking grass.  Whatever the product, the package label should contain three numbers, such as 26-3-3, 6-4-2, or 10-10-0.  The first number is the most important; it refers to the percentage of nitrogen present.  The second number refers to phosphorus, the third to potassium.  If one of the numbers is zero, that element isn’t included.

Nitrogen stimulates leaf growth and helps grass maintain a rich green color.  Less important to lawns, phosphorus promotes sturdy cell structure and healthy root growth and aids in flower and fruit production.  Potassium helps plants with normal plant functions and development.  When you buy a fertilizer specifically formulated for grass, these three elements should be in proper balance.

Nitrogen—Key to Green Lawns

Lawn fertilizers contain nitrogen in either an organic or inorganic form.  Organic fertilizers work slowly because bacteria must convert them into nitrates that roots can assimilate.  Sources are sludge, cottonseed meal, or other products derived from plants or animals.  Inorganic fertilizers are of two types: “fast acting” for immediate results and “slow release” for prolonged nutrient delivery.  The fast-acting types must be applied carefully as over-application will “burn” a lawn.  Slow-release fertilizers work over a longer period of time so they are less likely to burn.

• You may find nitrogen listed on fertilizer labels under these names:
• Nitrate or nitgrogenous.  Nitrogen is an immediately available form; not dependent on air or soil temperatures.  Fast-acting.
• Ammonical or ammonic.  Bacteria in soil are needed to break down the ammonia into nitrates.  Fast-acting.
• Urea.  A more complex compound than ammonia; bacteria convert it to ammonia, then nitrates.  Fast-acting; use with care to prevent burning.
• Urea-form, urea-formaldehyde, or “slow-release.” Artificially combined with resin to give slow, long-term release of usable nitrates.

Information accredited to Sunset Lawns & Ground Covers.  Page 16.