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Fertilize Naturally—
Is Feeding Frenzy Really Needed?

Written by UC Master Gardener Dan Vierria

Before reaching for fertilizer, ponder this: the runoff that eventually swirls down storm drains pollutes our waterways. Aquatic life and the quality of drinking water can be affected. Those who wonder if plants need nitrogen, phosphorous or potassium (The Big Three of fertilizers) might also ask “Do I need fertilizer at all?”

Determine plant needs

Fertilizers often are regarded as the cure-all for ailing plants, browning lawns and struggling trees. More often than not, lack of essential nutrients is not the problem. Too much water, the same abundant use of water that washes excess fertilizer down storm drains, may be the likely suspect. Moisture imbalances in soil, either too much or too little water, are the No. 1 environmental factor that impacts plant health. It’s always a good idea to inspect irrigation systems for clogged emitters and spray heads, broken pipes, errant spray patterns and incorrect timer programs.

Other symptoms of nutrient deficiencies could be caused by unhealthy roots, poor soil conditions, or improper care.

Fortunately, California soils contain most of the elements essential for plant health. In the Sacramento area, soils may be deficient in nitrogen. A soil test can determine if nitrogen is needed. Inexpensive soil-testing kits can be purchased at nurseries and more detailed testing can be submitted to soil-testing labs.

Consider replacing lawn

Lawns demand more frequent irrigation and nitrogen use than shrubs and trees. Consider replacing or reducing large turf areas with plants that require less fertilizer and water. Buffalograss and zoysiagrass are among alternative turf choices that require about half as much nitrogen as traditional turf choices. A mulching mower that returns grass clippings to your lawn can provide as much as 20 percent of a lawn’s fertilizer needs.

Several woody ornamentals, like nonflowering trees and shrubs, don’t need fertilizer, even at planting. Plants that are most-often thirsty for fertilizer feedings are flowering shrubs, some annuals and fruit trees and actively-growing turf.

Use fertilizer wisely

Using more fertilizer than the label recommends is never a good idea. Carefully read and follow label instructions when applying fertilizers. If you can’t read the small print on the label, go online and increase the font size for easier reading. Too much nitrogen can cause excessive growth and increased pest and disease problems. Excessive growth demands more water, too. Salts in nitrogen fertilizers also can damage roots.

Fertilizers are marketed in two categories—inorganic or chemical fertilizers and organic. While organic fertilizers are derived from plants and animals (seaweed, fish, bone meal, etc.), they can still be harmful to the environment and contribute to surface and ground-water pollution if used improperly.

When fertilizer is needed, use a slow-release type that will nourish plants throughout the growing season and is less likely to runoff into storm drains. Use the recommended rate of application and fertilize at the optimum time for the plants being fed. Always keep fertilizer off hard surfaces like driveways and walkways where it can easily be washed into gutters and down storm drains. The responsible use of fertilizer is a key component to being stewards of the environment.

For more information


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