LAYING THE GROUNDWORK.

Great gardens bloom in the spring, but they begin in the fall.

To get those cheery daffodils, tulips and other signs of spring, you've got to work hard this month feeding and fluffing the soil, says Lisa Norrick, education specialist for the Arboretum of Los Angeles County.

``The valleys may be too hot for actually planting flowers right now, but it's the perfect time to freshen up your flower beds by digging up the soil, amending it with mulch or a time-release fertilizer'' - not both - ``and other soil supplements. It's also time to pull out last season's straggly bedding flowers and any weeds,'' Norrick says.

The early part of September is also a great time to create new beds, says Better Homes & Gardens garden editor Michael McKinley.

``Since the valleys often have a desert type of soil, I recommend amending the soil with peat moss,'' McKinley says. ``However, if you have caliche, that hard (crusted calcium carbonate) layer found throughout the area, you'll have to drill through it to provide drainage with a soil auger that you can rent from local garden centers. Otherwise your new plants will drown in the water that's just sitting on the hard caliche shelf.''

McKinley says another solution to caliche is raised beds, built above the ground and filled with new soil.

``Whether you dig up existing soil or create above-ground beds, it's best to amend the soil two weeks before planting so it will ferment. That way, bacteria can recolonize the new soil and you'll give your plants or trees a healthy start.''

What to plant

OK. You've got the soil prepared and you're ready to plant. But visit a nursery to see what's suitable for the season.

``Although fall is the major planting season, it's not the time to plant bare-root roses and stone-fruit trees (plums, peaches and apricots) as those need to wait until spring,'' says Norrick.

Traditionally, this is bulb-planting season, say garden experts, who add that daffodils are the heartiest for the Los Angeles area and should be planted between mid-September and late October.

``Daffodils will come back year after year, unlike tulips and hyacinths, which need a winter chill and need to be replanted each fall,'' says Joan McGuire, one of the Arboretum's curators, who adds that bearded iris can also be planted now, or dug up and divided and replanted for best growth.

``But don't stop with daffodils,'' McGuire continues. ``Add interest to your garden with some of the smaller, more unusual bulbs, such as babiana, freesia and anemones, a low-growing plant with daisy-shaped flowers.''

Whichever type you choose, pay attention to the package instructions.

``The general rule for planting bulbs is to plant them 2 1/2 times the width of their diameter, from the top of the bulb,'' says Norrick. ``And also keep in mind that when the instructions say to plant 8 inches deep, what it really means is that there should be 8 inches of soil on top of the bulb, so dig deeper and fluff up more of the soil to give the roots a chance to grow.''

Before it rains ...

As soon as the weather cools down into the '70s - but before the rainy season starts - select bedding plants.

Experts say to pass on the flowers in bloom and buy those with buds, and to plant early in the morning or late in the day so plants won't be so stressed.

McGuire suggests candytuft, baby snapdragons, pansies, forget-me-nots, African daisies and primroses. Her favorite is the primrose, not just because of its brilliant colors, but because it will come back the following year if you just let it ``die back'' instead of removing the plant when it's finished blooming.

Regardless of the type of flower, McKinley suggests slowly introducing the plants (usually sold in a plastic six-pack) to their new environment. ``Put them on the patio, getting a little more sun each day (for up to a week) and then remove them by pushing up from the bottom. Plant in the renewed soil and let rest for about two weeks,'' says McKinley, who adds that new trees should be introduced to the local soil in the same manner.

It's also the ideal time to sow seeds.

Unfortunately, the Valley has hot weather and dry Santa Ana winds that wreak havoc with a seed garden, but California State University, Northridge, botanic garden manager Brian Houck has a solution.

``Planting seeds in flats is the best way because the seeds aren't introduced to any bacteria or fungus and can be in a protected environment,'' he says.

To prepare a flat, Houck says you have to sterilize it first, by washing it out with a 10 percent bleach solution; rinse well and then cover the bottom with newspapers. Next, he adds vermiculite, a heat-expanded mica (soil additive) that holds water and allows air to flow around the seed.

``After that, I use my finger to create rows and plant the seeds,'' he says.

It takes a little effort, but Houck's CSUN students have had success, getting as many as 100 plants from a $2 package of seeds.

Of course some seeds are simpler to sow than others.

``The absolute easiest seeds to plant here are California poppies,'' says Robin Pokorski, president of the Southern California Garden Club, which holds monthly programs that are open to the public.

She and other experts say all you need to do is throw the seeds over a well-prepared flower bed (a method called broadcast seeding) and rake the soil a bit with your fingers.

``Don't poke them in the ground like other seeds, as they just need minimal soil contact to germinate.''

Other California native wild flowers Pokorski recommends for novice gardeners are lupine, tidytips, Chinese houses and baby blue eyes, available in seeds at garden centers.

Water, water everywhere

At the Sepulveda Garden Center in Encino, where 400 gardeners grow vegetables in rented plots, senior gardener Patricia Jones says that keeping seeds moist when the winds blow is a constant challenge.

``Planting by seeds can be tricky, so a beginner may want to start with radishes. They, and carrots, are the easiest to germinate from seeds and that's why they're often used in local school projects.''

For more experienced gardeners, Jones recommends broccoli, brussels sprouts, all of the lettuces and spinach for local soil.

Whether it's new citrus trees, bulbs, poppies or radishes, the Arboretum garden experts stress careful watering to let the roots take hold. Don't overwater. Wait until the soil feels dry to the touch when you stick your finger in.

``New plants, such as pansies, like slow, deep water every two or three days while the weather is still hot, so you may want to invest in a water meter and save your fingernails,'' says McGuire.

Since you've already amended the soil to its healthiest state, these experts say plant food shouldn't be necessary in the coming few weeks. Later, as the plants - particularly rose bushes - mature, you may want to try a plant food such as Miracle-Gro.

``But don't blast the plant with the food. It's better to dilute it more than the manufacturer suggests, and then feed more often - maybe every two weeks,'' McGuire explains.

Once you've got the garden in order, get out a rake. As soon as there's a cold night, trees will drop their leaves.

The rake that experts recommend is a long-handled flexible-tine style, with a smaller, shorter model for getting around shrubs.

Buy bulbs now, plan for planting

For a beautiful spring garden, plan ahead. According to the Netherlands Flower Bulb Information Center in New York, Southern Californians should buy bulbs now and refrigerate until mid-October. While you're waiting, check out these tips on how to get the best bulb blooms:

Choose a sunny spot. Most bulbs like to be planted in full sun, although they can tolerate partial shade. Since bulbs will bloom before most trees leaf out, it's OK to plant underneath deciduous trees.

Plant bulbs in soil that drains well. Since soggy soil will rot the bulbs, avoid planting in places where water collects, such as at the base of hills or hollows. When preparing the planting site, be sure to work the soil well and mix in organic compounds such as compost or peat moss.

How deep to dig? Large bulbs, such as tulips or daffodils and hyacinths, should be planted about 8 inches deep. Small bulbs, such as crocuses or grape hyacinths (Muscari), are planted 5 inches deep, but check for directions on the package. Be sure to work the soil several inches deeper than you plant the bulb so the roots have plenty of room to stretch out.

Plant bulbs in groups. The biggest mistake that novice gardeners make is planting bulbs in a single row along a walkway. To get the maximum color impact, cluster your bulbs in a circular grouping for a bouquet effect or a triangle pattern with the narrow point facing you to give the appearance of more flowers than you actually planted.

- B.D.

What's happening

It's not too late to get a green thumb with these upcoming gardening classes and events:

Tuesday

Planting Iris; Allergy-free Gardening - The Southern California Garden Club will hold its monthly meeting and workshops at the Sepulveda Garden Center, 16633 Magnolia Blvd., Encino. Accredited iris judge Jane Troutman will discuss how to plant iris rhizomes at 9:30 and 10 a.m. Tom Ogren, author of ``Allergy Free Gardening,'' will explain which plants cause the least sneezing. Free; open to public. Reservations: Robin Pokorski, [phone].

Wednesday

Green Side Up: Fall Gardening Basics - An eight-week hands-on course for beginners, starting Wednesday, at the Arboretum of Los Angeles County, 301 N. Baldwin Ave., Arcadia. The course will be taught by Arboretum gardening expert Lisa Norrick, who will cover plant biology, fertilizers, mulch, dividing and transplanting, pest management, pruning, tools and basic garden design. Class hours are 2:30 to 4:30 p.m. on Wednesdays in the Education Greenhouse. Fee: $90. [phone].

Fall Planting - An afternoon workshop on soil preparation and plant selection for fall and spring gardens will be held at the Huntington Library and Botanical Gardens, 1151 Oxford Road, San Marino. The class will be taught from 3 to 5 p.m. by Katarina Eriksson, head gardener of Huntington's perennial gardens. Fee: $20. Advance reservations required: [phone].

Thursday

Pruning Trees and Shrubs for Optimum Health and Beauty - A slide show, lecture and demonstration of pruning techniques will be held at 2:30 p.m. at the Huntington Library and Botanical Gardens, 1151 Oxford Road, San Marino. Free. Reservations: [phone].

Sept. 15

Fall Botanic Garden Series - This California State University, Northridge, Extension program offers a variety of hands-on programs that feature local garden experts, authors and botanists as well as museum directors and biologists as speakers. The first two, which will be held Sept. 15, are ``Selecting and Growing African Violets'' from 9 a.m. to noon and ``Feng Shui in the Garden'' from 2 to 5 p.m. Fee for each one-day class: $49. To register: [phone] or on the Web at www.csun.edu/exl.

Sept. 22

Plant Materials I - Landscape architect Kenneth Kammeyer will teach this UCLA Extension course on plant texture, density, form and color with overnight field trips to nurseries and gardens. The seven-week course begins at 9 a.m. Sept. 22 at the Public Policy Building, Room 2270 at UCLA. Fee: $460. [phone].

Sept. 29

Native plant sale - Horticulturists and other expert gardeners will be available to help with the purchase and planting of native plants, such as white and purple sage and sticky monkey flowers, at Soka University of America, 26800 W. Mulholland Highway, Calabasas. Event will be held from 9 a.m. to 1 p.m. Free. [phone].

Rose Workshop - A five-week course on everything you need to know about roses, from planting to disease control, will be held at Huntington Library and Botanical Gardens, 1151 Oxford Road, San Marino. The fee is $75 and includes a field trip. Hours are 9 to 11:30 a.m. Saturdays. Registration: [phone].

Oct. 2

Native Plants - A garden tour and lecture on native plants will be held at Soka University of America, 26800 W. Mulholland Highway, Calabasas. The free program will give instructions on how to grow native plants in your garden. Class hours are 10 to 11 a.m. Reservations: [phone].

Oct. 3

Planting Design for the Home Gardener - The principles of design as applied to the home garden will be taught by landscape architects Anna Armstrong and Richard Walker in a 12-week course at the Public Policy Building, Room 1270. The course will be held from 7 to 10 p.m., and college credit is available. Fee: $270 for credit, $210 without credit. [phone].

Oct. 13-14

Native Plant Sale and Gardening Festival - This event is sponsored by the California Native Plant Society and will be held from 10 a.m. to 4 p.m. at the Sepulveda Garden Center, 16633 Magnolia Blvd., Encino. There will be expert gardeners available to assist with selection and garden planning, demonstrations, garden books and activities for children. Free. [phone].

- Barbara De Witt

CAPTION(S):

10 photos, 2 boxes

Photo:

(1 -- cover -- color) `This is the season'

For a glorious display of spring color, start preparing your garden now

(2 -- color) Laying the groundwork

(3 -- color) SCILLA SIBERICA

(4 -- color) NARCISSUS ``HAWERA''

(5 -- color) PUSCHKINIA LIBANOTICA

(6 -- color) Step 1: Measure the bulb to determince depth of hole.

(7 -- color) Step 2: Dig hole with a garden trowel.

(8 -- color) Step 3: Check depth of hole before covering bulb.

(9 -- color) Step 4: Lisa Norrick of the Arbetorum of Los Angeles County mixes bulb planting mix and fertilizer into the soil before covering up the bulb.

(10 -- color) Step 5: Enjoy your efforts in the spring.

Gus Ruelas/Staff Photographer

Box: (1) Buy bulbs now, plan for planting (see text)

(2) What's happening (see text)