Feeding Time

Spring`s The Time To Take A Hard Look At Your Plants` Diet

March 15, 1991|By William Aldrich.

Squanto, as you no doubt recall from your early elementary school years, was that fellow who showed the Pilgrims how to fertilize their corn crop by putting a fish in the planting hole.

Fast-forward to today and you can find that same principle being applied- only now it`s a ``secret`` and the name is trademarked. Indeed, a company called Offshore Ventures Ltd. is bringing the gardeners of America ``Squanto`s Secret,`` heralded as ``the logical organic choice.``

What Squanto knew then was that decaying fish enriched the soil, making crops grow better. Now ad copy writers throw around such claims as: ``The amino acids that are hydrolyzed from the fish can be utilized directly by plants.``

However it is phrased, the plants we grow need a diet that is rich in the proper balance of nutrients. If a plant`s root system is in a sterile medium, it will not thrive. Corn planted in Illinois grows bountifully because of the nutrient-laden soil here.

This month is a good time to polish up on feeding plants. As days lengthen and the sun`s strength increases, plants that have been sulking on the kitchen window sill can be coaxed into active growth; the lawn is beginning to shake off the winter grays and could stand some help; and the vegetable garden most likely will be turned when the soil dries, and its nutrient balance should be addressed, too.

Because there are so many areas of our home and landscape that need diets adjusted in the spring, we should distinguish between organic food, such as Squanto`s Secret, and products that aren`t organic. Also worth considering is whether liquid is better than granular and whether slow-release products are better than fast-working fertilizers.

Room for confusion

Steve Ettlinger has written a book about the traumas many of us will suffer this month during a trip to the garden center. In researching

``Everything Sold in Garden Centers`` (Macmillan Publishing, $24.95), Ettlinger asked garden center managers what shoppers were most ignorant about. `` `I need fertilizer,` they`d say, but they would have no idea what they needed it for,`` Ettlinger said. ``I picked up a series of fancy packages one time and started examining the labels like you would a wine bottle to determine what level of quality it was.

``One label said it was for fruit and vegetables, another for flowers, another for the lawn-and they all had basically the same formulation. I asked the manager what the difference was and if I were a gardener and wanted to feed all these types of plants, was I liable to buy three or four containers of fertilizer? He said yes, you would likely buy all of them despite the fact they were basically the same fertilizer.``

In general, making sure a plant is in its proper environment (the right soil, temperature, humidity) is more important than giving it fertilizer. A good fertilizer might help, but it won`t perform miracles.

Still, the first step in understanding fertilizers is to know how to read those numbers that stare back at us from the label.

Fertilizers are rated by the amount of three basic nutrients they contain: nitrogen, phosphorus and potassium (also known as potash). Known as the N-P-K nutrients, the numbers on a fertilizer container correspond to the percentage of each in the product. For instance, a 50-pound bag of 20-20-20 contains 10 pounds (20 percent) each of nitrogen, phosphorus and potassium and 20 pounds (40 percent) of inert ingredients that bond with the fertilizer.

Where fertilizers vary is in the ratio of N-P-K and the speed with which those nutrients become available. Lawn food often has a high nitrogen content for quick greening of the grass blades. Fertilizer designed for flowering plants often has a high phosphorus content.

This can be the start of serious confusion, so a track back to the start might be in order:

- Liquid and powder fertilizers are essentially the same. Both are diluted with water to a minute strength. Because they are suspended in water and poured directly onto plant roots (or sprayed on the foliage), they can be utilized by the plant within seconds, said Robert Hagedorn of Stern`s Miracle- Gro.

The advantage of this feeding method is that it is ``precise; you put down what you need when you need it,`` Hagedorn said. The fertilizer is used up quickly and needs to be reapplied within a few weeks in most instances.

- Granular fertilizers (lawn products and general garden fertilizers often are sold this way) are applied dry and dissolve slowly with watering. The aim of most of these is to release nutrients slowly over several months to feed the plants steadily.