Summer is not created equal.

In parts of the Central Valley, blast-furnace heat parches people as well as gardens. In the Sierra foothills, temperatures waver between warm and icy cold.

At higher elevations, it's even more unstable: Snow and hail fell on Donner Summit early this month.

What's a gardener to do?

Get in touch with your microclimate.

In California, growing conditions can be all over the zonal map, even in one backyard, observed Claire Splan, author of the new "California Fruit and Vegetable Gardening" (Cool Springs Press, $22.99, 256 pages).

"The challenge with the book was the wide variety of climates in California," said Splan, who lives and gardens in Alameda. "Trying to make a garden here is like gardening on planet Earth – we have a little of everything."

The best way to determine what you can and can't grow is to try, she added.

"I want to get people out, doing things, getting familiar with their own microclimates," Splan said. "Our weather is changing. I've lived in Alameda my whole life, and it's not the same climate I grew up with – it's hotter. We have to adapt. It's one more challenge for gardeners."

Summers tend to be challenging for gardeners, anyway. Besides heat, there's pressure to keep water bills down.

Mulch can go a long way toward keeping the ground evenly moist and cool. Mulch means less water used, less money spent and less worry.

Move the mulch around, too, so it doesn't pile up around the trunk of the plants (that can cause rot), advises landscape designer Cheryl Buckwalter, one of the Regional Water Authority's Blue Thumb bloggers.

"Move the mulch at least several inches away from the base," she said. "This improves air circulation and reduces the chance of damage, disease and unwanted pests from making themselves at home.

"Then add a fresh layer of mulch to a depth of 2 to 3 inches so your plants, soil and soil organisms can enjoy the many benefits of this inexpensive and easy action that also gives your garden a fresh look."

Speaking of water, summer is a good time to tune up irrigation as well as target water wasters throughout the house. Most water agencies offer free Water-Wise House Calls with advice on how to keep little drips from adding up to big bills. (Learn more at www.BeWaterSmart.info.)

"Check the drip system," Buckwalter said. "Check polyethylene tubing on the soil surface for damage and breaks due to heavy foot traffic, chewing from animals, etc. Repair leaks and broken lines. Clean and replace emitters."

Once lines are repaired, cover them with mulch to avoid any more disruptions. To be effective, emitters should be placed directly on the soil, not on top of the mulch.

Check to see what's not getting watered, too. You may need to adjust the placement of emitters farther away from shrub or tree trunks as plants grow.

Turn on the sprinklers, Buckwalter added. The spray from one sprinkler head should reach the head of the adjacent sprinkler. If not, clear blocked or clogged heads.

You may need to replace mismatched nozzles and consider installing water-saving rotary nozzles, she added. Adjust misaligned, tilted and obstructed heads.

Remember: "The target for the water is the lawn, not fences, sidewalks, streets or houses," Buckwalter said.

If water is running off, adjust your timers. Consider installing a "smart" controller that automatically adjusts irrigation to the weather.

And watch out for places where water can accumulate, such as saucers under pots or neglected pools. This is shaping up to be a bad mosquito summer.

According to the Sacramento-Yolo Mosquito and Vector Control District, late-spring storms created breeding grounds for mosquitoes. Making matters worse, dozens of mosquito samples and several dead birds have tested positive for West Nile Virus.

"We're very concerned about the level of intense activity we're seeing this season," said district manager David Brown. "While it's not uncommon to find widespread areas with dead birds and mosquito samples in August, finding virus activity in June is certainly earlier than anything we've seen in recent years, and we urge residents to take these early indications seriously."

On the flip side, this weather is good for gardening. With such a mild late spring, it's not too late to plant some vegetables, which continues to be the hottest trend in gardening.

"Most people get into it because of one or two particular things they want to try," Splan said. "They're not happy with the quality they get in the supermarket or they want a different variety."

As always, there's one backyard crop that dominates that list.

"No. 1, they want really good tomatoes," Splan said. "Tomatoes are the gateway drug of gardening. From there, add a little zucchini, a little basil, a few peppers. Before they know it, they're full-fledge veggie gardeners."

In Splan's tomato section of the garden, she planted "the best-tasting ones," she said. That includes Big Mama (a hybrid Roma), the heirloom Black Krim and the sweet Black Cherry.

"My dirty little secret is that I actually hate tomatoes," Splan said. "I grow great plants, but I give the tomatoes away."

Good news for procrastinating gardeners: It's not too late to get started. To make up for lost growing time, plant some healthy transplants, but look for ones that haven't yet started to set fruit.

Put them in a sunny spot, give them water three times a week and fertilize once or twice a month.

"Just grow something," Splan said. "Later this summer, you'll be glad you did."

YOUR SUMMER TO-DO LIST

Pace yourself; there's plenty to do this summer. Here are some suggested gardening jobs, courtesy of UC master gardeners:

Late June

• Let the grass grow longer. Set the mower blades high to reduce stress on your lawn during summer heat. To cut down on evaporation, water your lawn deeply during the wee hours of the morning, between 2 and 8 a.m.

• Tie up vines and stake tall plants such as gladiolus and lilies. That gives their heavy flowers some support.

• Dig and divide crowded bulbs after the tops have died down.

• Feed summer flowers with a slow-release fertilizer.

• Mulch, mulch, mulch. This "blanket" keeps moisture in the soil longer and helps your plants cope during hot weather. But don't let mulch mound around trunks or stems; that can cause rot.

• Warm weather brings rapid growth in the vegetable garden, with tomatoes and squash enjoying the heat. Deep-water, then feed with a balanced fertilizer. Bone meal can spur the bloom cycle and help set fruit.

• Feed camellias, azaleas and other acid- loving plants. Mulch to conserve moisture and reduce heat stress.

• Cut back Shasta daisies after flowering to encourage a second bloom in the fall.

• Trim dead flowers from rosebushes to keep them blooming through the summer. Roses also benefit from deep watering and feeding now. A top dressing of aged compost will keep them happy. It feeds as well as keeps roots moist.

• Plant basil to go with your tomatoes. There's still time to plant melons, pumpkins and squash from seed. Throw in a few sunflowers, too.

• Transplant summer annuals such as petunias, marigolds and zinnias. It's also a good time to transplant perennial flowers including astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia, salvia and verbena.

July

• Keep your vegetable garden watered, mulched and weeded (easier said than done). Attack weeds while they're small and before they flower.

• Pinch back chrysanthemums for bushy plants and more flowers in September.

• Feed vegetable plants bone meal or other fertilizers high in phosphate to stimulate more blooms and fruiting.

• Remove spent flowers from roses, daylilies and other bloomers as they finish flowering.

• Pinch off blooms from basil so the plant will grow more leaves.

• Cut back lavender after flowering to promote a second bloom.

• It's not too late to add a splash of color. Plant petunias, snapdragons, zinnias and marigolds.

• From seed, plant corn, pumpkins, radishes, winter squash and sunflowers. Here's a tip from champion pumpkin growers and pumpkin patch pros: The biggest Halloween pumpkins get their start on July Fourth. Plant your future giants in early July.

August

• Harvest tomatoes, squash, peppers and eggplant. Prompt picking will help keep plants producing.

• Feed citrus trees their last round of fertilizer for the year. This will give a boost to the fruit that's now forming.

• Harvest tomatoes, beans, squash, pepper and eggplants to prompt plants to keep producing. Give your plants a deep watering twice a week, more if they look droopy or are in containers. Also, give them a boost with phosphate-rich fertilizer to help fruiting. (Always water before feeding.)

• Pinch off dead flowers from perennials and annuals to lengthen their summer bloom.

• Pick up after your fruit trees. Clean up debris and dropped fruit; this cuts down on insects and prevents the spread of brown rot. Then, feed fruit trees with slow-release fertilizer for better production for next year.

• To prolong bloom into fall, feed begonias, fuchsias, annuals and container plants. Always water before fertilizing.

• Fertilize fall-blooming perennials, too. Chrysanthemums can be fed until the buds start to open.

• Divide and transplant bearded iris. This job should be done every three years to keep iris blooming strong in spring.

• Prepare for a fall full of flowers by paying a little extra attention to your garden. Cut off spent blooms from roses, annuals and perennials, then give them a boost of fertilizer. Roses will rebloom about six to eight weeks after faded flowers are removed.

• Indoors, start seedlings for fall vegetable planting, including bunching onion, cabbage, broccoli, cauliflower, kale, radicchio and lettuce.

• Sow seeds of perennials in pots for fall planting including yarrow, coneflower and salvia.

• Start your fall vegetable garden outdoors, too. Direct seed beets, carrots, leaf lettuce and turnips. Plant potatoes.

– Debbie Arrington

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