IN THE GARDEN IT'S SOMETHING IN THE WATER.

Imagine that every time you turned on your sprinklers, your lawn and garden were automatically fertilized with no extra effort on your part. Then imagine that your sprinkler water carried not only liquid fertilizer but also organic polymers that would, in time, reduce by up to 50 percent the amount of water you needed to apply to your lawn and garden.

If you can imagine such a scenario, you can appreciate fertigation, which injects fertilizer into the irrigation stream and has been used for decades in nurseries. If you ever wondered why plants at your garden center are always so lush and full of flowers, consider that fertigation, in one form or another, has probably been utilized in their development and growth.

Fertigation removes the headaches associated with conventional fertilization. Novice and experienced gardeners alike never cease to wonder about when, how much and at what concentration they should fertilize. Not to mention trekking to the nursery and lugging home heavy bags of fertilizer, and then worrying over dispersing their granular contents effectively.

With fertigation, a small tank is set up next to the main irrigation line and a diluted concentration of liquid fertilizer flows from the tank into the irrigation pipes with each watering. A double-check valve, back-flow prevention device must be installed between the main line shut-off and the fertilizer tank.

A constant, diluted fertilizer is as beneficial to plants as a constant healthy diet is beneficial to people; it's a smart alternative to the instant growth produced by high-concentration fertilizers, which is not healthy for plants and creates additional work for gardeners.

What's more, recent research at California Polytechnic State University, Pomona, and the University of Florida has shown that organic polymers known as soil surfactants can also be injected into the irrigation system to speed water infiltration into the soil and retard water evaporation out of the soil. The overall result is extraordinary water savings. According to the studies, when soil surfactants are injected into the irrigation system, water application can be reduced by up to 50 percent or more.

The company leading the way in fertigation technology is FertiGator. Their latest product is called Mojo, which, injected into the irrigation system, provides fertilizer and soil surfactants as well as ingredients that repel gophers, deer, rabbits, fire ants and grubs, with no toxicity to people or pets. The company can be contacted at [phone] or on the Web at www.fertigator.com.

TIP OF THE WEEK: Carol Lambert from Lake Los Angeles issues an illuminating caveat about turning horse manure into humus - for soil building purposes - through the use of red wriggler worms. ``Anyone composting horse manure must ask the owners of the horses if they have recently been de-wormed, since the worming medicine will also kill fishing worms used for composting.

``I de-worm my horses twice a year. I keep manure from the de-wormed horses separate from my compost for about a week to protect the worms in the compost. Manure from de-wormed horses can be used right away if it is spread over the soil surface for weed control.''