IN THE GARDEN FOUR STEPS TO SPRING PLANTING SUCCESS.

Byline: JOSHUA SISKIN

Two weeks shy of its official arrival, spring may as well be here. In the Valley, spring comes in the winter, and summer typically shows itself in early spring. With these facts of local climatology in mind, the sooner you plant your spring garden, the better your plants will grow when hot weather comes, which could happen as soon as late March or early April.

The recent arrival of marigolds and petunias at the neighborhood nursery is a sure sign that spring planting is upon us. Marigolds and petunias should be planted as soon as possible so they can establish their root systems before our first heat wave sets in. A few hot days following planting can have a lasting negative effect on a plant's development.

Fortunately, there are ways of buffering the effects of unexpected weather extremes that may occur soon after your plants are in the ground. Four soil treatments will go a long way toward ensuring garden success, regardless of the weather, especially when planting vegetables and annual flowers that often flounder a short time after being placed in the ground. If you indulge your soil in these four treatments, I can almost guarantee that you will be a more successful gardener than you ever thought possible.

1. Dig up your soil to a minimum depth of 6 to 10 inches. A well-dug, aerated soil will welcome the growth of roots of young plants far more than a soil that is merely turned over on the surface.

2. Add soil amendments. Not to be confused with fertilizers, amendments - which consist of composted wood shavings, green waste or sewage sludge - will either soften hard soil and improve drainage or, in the case of highly sandy soil, improve water-holding capacity. Amendments are also friendly to aerobic soil bacteria, those important soil dwelling decomposers that make soil minerals available to plants and turn themselves into highly beneficial humus (sometimes defined as the skeletal remains of bacteria) when they die. Humus contributes to the overall health of the soil and depresses the growth of pathogenic soil organisms. For a soil that needs improvement, add 8 cubic feet of amendment per 100 square feet of planting area. Once your soil has been substantially improved, you will probably not need to add more than 2 cubic feet of amendment (per 100 square feet of growing area) per year.

3. Add fertilizers. Humus containing formulations such as those in Grow More and Gro-Power products are probably the best fertilizers on the market. Add phosphate rock to ensure quick root growth and plentiful flowers. Organic fertilizers such as cottonseed meal are also recommended.

4. After you have planted, put a layer of mulch on the soil surface to conserve moisture and keep roots cool. Lately, I have been using cedar chips (with nitrogen added), an inexpensive mulch sold by the bag, for this purpose. Homemade compost, a mixture of shredded prunings, grass clippings, and vegetable and fruit peels, also makes a fine mulch. If you have done steps 1 through 3 above, step 4 may not be necessary. Ted Howard, a distinguished Valley horticulturist I consulted regarding the above soil treatments, says that annuals planted several inches apart from each other in properly prepared soil will grow so quickly that, soon enough, no bare soil will be visible between them. His flowers create a living mulch with their foliage, covering the entire soil surface so that evaporation from the soil is minimized and water conserved. To my knowledge, Howard is the only person in Los Angeles who makes a living exclusively from planting flower beds. He plants most of his annuals from six packs, and they last for half a year so that only two plantings per year are needed. He stresses the importance of dead-heading - snipping off finished or wilted flower heads - to extend bloom time of annuals.