Fertile Imagination : When it comes to feeding your plants, there’s a dizzying array of choices. Become familiar with your garden’s needs will make the decision easier.

We know that feeding plants is important. Most greenery requires nourishment to thrive. Unfed plants might lose vigor and develop health problems.

The dizzying array of fertilizers on the market, though, makes feeding plants intimidating and confusing. Choosing an appropriate fertilizer can baffle even experienced gardeners.

Perhaps the biggest decision you’ll have to make regarding fertilizers is whether to go organic or chemical--unless you choose to straddle the fence. Some plant foods are chemical, such as the popular Miracle-Gro; others are more natural in origin, such as manures.

The main benefit of chemical fertilizers is their quick absorption by plants. Organic fertilizers take longer to get to plants because they need to be broken down first and don’t release nutrients to plants in cold weather. An argument for using them is that since they are slow to release, they don’t burn plants as chemical fertilizers can if applied too heavily.

Chemical fertilizers can generally be recognized by the high numbers on their labels, such as 26-26-26. These numbers are the fertilizer’s NPK ratio, which explain the percentage of nitrogen, phosphorus and potassium in the fertilizer.

Organic fertilizers tend to have lower NPK levels, such as rock phosphate (0-3-0). Organics also tend to be alive with microorganisms that feed the soil.

Examples of organic fertilizers include manure, blood meal, bone meal, fish emulsion, seakelp, bat guano, greensand, cottonseed meal, gypsum and rock phosphate, which is the mined skeletal remains of prehistoric animals.

No matter what type of fertilizer you choose, it will feed your plants, says Lois Chaplin, horticulturist for Pursell Industries in Sylacauga, Ala., which makes a variety of widely available time-released chemical fertilizers.

“Plants pick up nutrients whether the food is organic or chemical,” she said. “Time-released fertilizers have a Polyon coating, which breaks down over time. With this coating, plants are given metered doses of plant food, which prevents burning and washing away.”

Despite advances in chemical fertilizers, some horticultural experts lean toward organic foods for one reason: Soil health.

“I used to use chemical fertilizers, and I fought the organic people for 20 years,” said Gary Matsuoka, president of Laguna Hills Nursery in Lake Forest. “Ten years ago, organic growers told me things grew better with their fertilizer products, but they couldn’t tell me why. Now, the latest research points to the fact that organic fertilizing builds the soil and encourages the production of crucial soil organisms like mycorrhizae. They’ve also found that soils where chemicals are used eventually become depleted and lifeless.”

Matsuoka contends that if soils are properly cared for, they can create fertilizer. “Mulching is the key,” he said. “As long as you maintain a mulch layer of 5 to 9 inches made up of whole dead plants from your yard such as grass, you create an ecosystem,” he said. “After two or three years, your garden will feed itself. Until then I suggest fertilizing with blood meal every two or three months to keep the nitrogen level up.”

One of the newer forms of fertilizer with its share of proponents and skeptics is rock dust, a natural mineral fertilizer. It is said to have a wide range of trace minerals, which some say are deficient in many soils. It is also touted for its ability to promote soil health.

When used correctly, a good rock dust will encourage and promote microbial activity in the soil, said Leslie Battjes, a Santa Monica distributor of ECO-MIN, which was developed by an Australian farmer and researcher.

“ECO-MIN contains over 60 minerals and trace elements that are released to the plants,” she said. “Not only has it been shown to make plants healthier and more prolific, many say fruits and vegetables taste better.”

Vermicompost is also used, although it’s not new. Often called “worm castings,” vermicompost is worm feces that provide a wide variety of nutrients to plants. In addition to creating compost, worms are prized for their constant tunneling which aerates Orange County’s heavy clay soils.

Whatever approach you take, consider these tips when feeding your plants:

* Forgetful, or have no time to feed? Try time-released fertilizers, which will get you off the hook for three to nine months. They are especially helpful in containers, although you might want to supplement pots with a liquid food occasionally. Remember to mulch plants, which will improve the soil, cut down on watering requirements and keep plant roots at an even temperature.

* Special diets. Some plants such as azaleas, camellias, citrus, gardenias and palms need a specific type of food to keep them thriving. Azaleas, gardenias and citrus, for instance, require an acid food with iron; without it, their growth becomes chlorotic (yellow), and the plants won’t thrive, bloom or fruit as well.

* Sampling the soil. The best way to find out what your yard needs is to take a soil sample, which will tell you the nutrient content and what you need to add to correct problems.

Take a sample up to 6 inches deep and deliver it to a soil and plant laboratory. Send more than one sample if you suspect the soil is different from one part of the yard to another.

* Foliar fertilizing. For quick results, spray fertilizer on the leaves, which is often more effective than ground feeding. This should be done with a fertilizer made for foliar feeding. Also be sure to add an adjuvant, which will make the fertilizer stick to the leaves, rather than bead up and slide off. Spray in the early morning or late evening; never when the sun is high, which can burn plant leaves.

* Soil temperature. In the winter months, many organic fertilizers and even some chemical fertilizers aren’t taken up by cool-season flowers. A Pursell product called Pansy Booster has a nitrate form of nitrogen for use in cool soils. It can also be successfully used on other winter-bloomers such as Iceland poppies, snapdragons and mums.

* Containerized plants. Potted plants rely on you to keep them fed. Generally, fertilizers wash through potted plants within a few weeks. Fertilize once a month or use a time-release fertilizer and supplement with occasional liquid feedings.

* Sick plants. Give an ailing plant proper water and sun and start fertilizing it when it’s looking better.

* Nitrogen deficiency. Orange County’s clay soils tend to be high in phosphorus and potassium, which aren’t very mobile, but nitrogen quickly leaches through all soil types and therefore must be applied on a regular basis. Nitrogen-poor plants are usually pale green or yellow. The foliage and stems may also be stunted, and the plant is likely to dispose of old leaves quickly as it moves what little nitrogen it has to new leaves for growth. Many fertilizers, such as blood meal and fish emulsion, are primarily nitrogen.

* Follow package directions. Many products have a different NPK ratio. Follow directions carefully.

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Resources

* Laguna Hills Nursery, (949) 830-5653.

* ECO-MIN, (888) 679-4353 or visit its Web site at https://www.oyi.com.

For worm castings, call Orange County Farm Supply, (714) 978-6500.