Timing key when adding fertilizer to landscape

TONY BERTAUSKI
The Post and Courier

Applying the proper fertilizer — and at the proper time — can turn your begonias from merely pretty (left) to pretty spectacular.

Timing is everything.

Banana and peanut butter is my snack of choice. What I do is take a bite of banana and follow it with a spoonful of peanut butter. The flavors mix as I chew. At 10 seconds (I don't actually count), I chase it with vanilla soy milk. It has to be timed just right to enhance the flavor. Yesterday, my wife took my glass of vanilla soy milk just as the window of enhancement arrived. I tried to be patient, but the moment was slipping away. Desperately, I shouted, "Timing!"

She knew exactly what I was talking about.

May is the time to fertilize. I realize most people have not been able to resist the temptation. After all, spring has sprung, so why wait until May? However, turf, trees and shrubs wake up slowly as temperatures fluctuate from warm to cool. Once May arrives, though, temperatures start fluctuating between warm and hot.

If you've already fertilized, it won't kill anything, but those plants could be worse off than if you waited until May.

When fertilized, plants consume more carbohydrates to produce new growth. Carbohydrates are food, the end product of photosynthesis.

A late frost or, God forbid, a late freeze will kill new growth. Fertilized plants have much more new growth that will be damaged and, subsequently, will be more susceptible to disease. Fertilized plants also are weakened because they have depleted their carbohydrate reserve and now have to start over.

Early fertilization, quite simply, is risky. So far this year, we have avoided late cold snaps. There's still a long-shot chance we'll get one in May (like last year), but it's unlikely. Waiting until mid-May is the safest time to fertilize.

The numbers game

A fertilizer has three numbers on the label that represent nitrogen, phosphorus and potassium, in that order. Nitrogen encourages new foliage, most important to turf. Phosphorus boosts flowering, most important to annuals and flowering shrubs (not so much for turf). Potassium increases temperature and water-stress tolerance.

Most fertilizers contain slow-release nitrogen, which is released into the soil over a period of one to three months. If nitrogen is not formulated for slow release, it causes a large flush of growth. You would mow your lawn three times a week and then it'd be gone.

Organic fertilizers are derived from plants or animals. Examples are blood meal, fish emulsion or processed sewage. Milorganite is one of the most popular commercial products. Organic fertilizers contain low amounts of nutrients that are released slowly as microorganisms break it down. The greatest advantage of organic fertilizer is that it feeds microorganisms that are vital to healthy soil.

However, most commercial products are synthetic because they are cost-effective. Sulfur-coated urea is commonly sold to homeowners for the lawn. Do not apply more than 1 pound of nitrogen per 1,000 square feet.

If the fertilizer has a 20-3-18 ratio, that means it contains 20 percent nitrogen, 3 percent phosphorus and 18 percent potassium. Here's a shortcut: Divide the nitrogen into 100 to find out how much fertilizer contains 1 pound of nitrogen. For example, 20 divided into 100 means that 5 pounds of fertilizer contains 1 pound of nitrogen. If you have 2,000 square feet of front lawn, you should use 10 pounds of fertilizer.

For trees, shrubs and flowers, polymer-coated fertilizer, such as Osmocote, is a popular synthetic product. These products typically have more phosphorus, such as 14-14-14, to boost blooms. For trees and shrubs, it can be sprinkled around the base of each plant beneath the mulch. For annuals, it can be broadcast over the soil before mulching or incorporated into the soil before planting.

For established trees and shrubs, fertilizing is optional. Fertilize, however, if you want to boost the growth or flower production.

By the way, not just any peanut butter will work with banana. It has to be Smucker's All-Natural Crunchy. Smooth peanut butter is just gross. I don't even know why they make it.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback or request specific column topics, e-mail Tony at tony.bertauski@tridenttech.edu.