Plants have different needs for fertilization

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Question: We have the drip system for watering all the plants and trees and palm trees. We are planning on having the fertilizer system added to the drip system. We were wondering if it is OK for the palms, or do they need their own special fertilizer and at only certain times of the year.

Fertilizer injectors were originally intended to be used when growing all one kind of plant, or plants, with similar fertilizer requirements. Not all plants have the same requirements. Most woody plants can do nicely with one, or perhaps three fertilizer applications per year.

In most cases, with woody plants, we want the fertilizer to "run out" as we enter the fall months. This encourages many plants to enter into dormancy as the dormant season approaches.

With continuous applications of fertilizers, some plants are encouraged to grow later in the season. In many cases, this will not be too much of a problem. In the case of winter-tender plants, then this can be a problem.

Encouraging growth of winter-tender plants into the fall months will cause their growth to be more succulent and tend to make these plants less tolerant of freezing temperatures. If it is possible, try to limit fertilizer applications with your injector after about the end of July to woody plants.

If you have annuals, flowering herbaceous plants, vegetables or turfgrass, you could apply fertilizers to these plants by hand, and thus avoid the possibility of continuously fertilizing tender woody plants.

When applying fertilizer to plants irrigated with drip, applying the fertilizer just under the emitters or using fertilizer stakes just a few inches off the emitters will push the fertilizer toward growing roots.

Foliar applications of fertilizers also work extremely well when applied during the growing season, as long as you apply them lightly and during the cool of the day.

Foliar applied fertilizers last only a couple of weeks and are usually reapplied when needed.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension.