Soil moisture is key to survival in triple-digit temperatures
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Spraying tomato plants with water early in the
morning helps fight spider mites and aphids while
refreshing the leaves and raising the humidity
around the plants. The runoff helps the plants, too.
(Photos: Kathy Morrison)
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As the weather forecasters like to say: We’re having a heat wave!
Triple-digit days dominate our Sacramento forecast at least through Saturday. In its Excessive Heat advisory, the National Weather Service warns, “Drink plenty of water; don’t wait until you’re thirsty.”
That same advice applies to your garden. Plants with roots in soil that stays evenly moist – not soggy – have the best chance of surviving, even thriving during this heat wave.
The secret is to keep the soil from completely drying out – not on top, but down 4 to 6 inches in the root zone. Use a moisture meter to check. Or use a long-handled screwdriver; if you can’t shove it in 6 inches, you need to irrigate.
Potted plants in containers are especially at risk. The rootball contracts as it dries out, leaving gaps around the sides of the pot. When you pour water on a severely dry potted plant, the water tends to run out the sides without ever penetrating the rootball. In such cases, you may need to submerge the pot in water, let soak for a few minutes, then drain. Don’t let the roots sit in standing water; they’ll suffocate.
Wilting in the heat of the afternoon is normal for many plants, especially those with big thin leaves such as hydrangeas or squash. But if plants are wilted in the morning, water immediately.
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Burlap or shade cloth can help prevent sunburn
on tomatoes or other summer vegetables.
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Spider mites in particular are loving this heat; this itty-bitty arachnid thrives in hot and dusty conditions. If you see wispy webs covering leaves and stems of shrubs and other plants, knock them down with a strong stream of water from the hose.
This summer shower destroys their webs and washes the mites and dirt off the plants. It also disrupts what attracted the mites in the first place – dry, dusty leaves.
Wash mites off plants early in the morning, so the plant’s foliage has all day to dry. Fungal diseases usually aren’t a problem right now; powdery mildew can’t stand anything above 90 degrees.
This same approach also works against aphids. Showering plants is not wasting water; the runoff will go to the plant’s roots. Most plants also absorb moisture via their foliage.
Avoid spraying neem oil or other treatments (often recommended for pest control). The oil coats the plant’s foliage and increases its sensitivity to extreme heat. Instead of helping the plant, the oil “cooks” its tender leaves.
And put off any fertilization until weather cools back to normal. Feeding increases a plant’s water needs. During this heat, it just adds to plant stress.
For more on heat stress and plants, check out this advice from the UC Integrated Pest Management Program: http://ipm.ucanr.edu/PMG/GARDEN/ENVIRON/thermal.html .
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Flowers in My Back Yard Series
July 28: Naked Ladies put on summer show
July 21: Thank Luther Burbank for these long-lasting beauties (Shasta daisies)
July 14: How to keep hydrangeas happy
July 7: Grow these bright cosmos for bees and butterflies
June 30: Agapanthus adds blue fireworks to the garden
June 23: Easy-care gazanias fill those hot corners
June 16: Daylilies are perfect for water-wise gardens (and a lot more)
June 9: Grow coneflowers for pollinators -- and yourself
June 2: Sunflowers capture Sacramento's summer attitude
May 29: Are your roses going 'blind'?
May 26: Zinnias are the summer flowers every garden needs
May 19: Plant dahlias now for late-summer flower power
May 12: Know your coreopsis from your bidens
May 5: Mums the word on Mother's Day weekend
April 28: Majestic Matilija poppy is worth a look
April 21: Celebrate roses, America's favorite flower
April 14: Small flowers with outsized impact
April 7: Calendulas do double duty
April 3: Make Easter lilies last for years to come
March 31: In praise of a pollinator magnet (small-leaf salvias)
March 24: Azaleas brighten shady spots
March 17: The perfect flower for beginners? Try zonal geraniums
March 10: Keep camellias happy for years to come
March 3: Fruit tree blossoms are a fleeting joy
Feb. 27: Are your roses looking rusty?
Feb. 24: Treasure spring daffodils now and for years to come
Feb. 17: How and why to grow wildflowers
Feb. 10: Let's talk Valentine's Day roses
Feb. 3: Why grow flowers?
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Garden checklist for week of Aug. 2
Get out early in the morning and monitor your garden’s moisture needs. Deep water and add temporary shade structures for plants that are feeling a little burned. In particular, protect developing peppers and eggplant.
* Put off fertilization until this heat passes; plants need to concentrate on hydration instead of growth.
* Harvest tomatoes, beans, squash, pepper and eggplants to prompt plants to keep producing. Give your plants a deep watering twice a week, more if planted in containers.
* Watch out for caterpillars and hornworms in the vegetable garden. They can strip a plant bare in one day. Pick them off plants by hand in early morning or late afternoon.
* Mulch can be your garden’s best friend – it conserves moisture while blocking out weeds. But don’t let mulch mound around stalks, stems or trunks. That can promote rot.
* 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.
* 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. Roses will rebloom about six to eight weeks after deadheading.
* 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.
* In the garden, direct seed beets, carrots, leaf lettuce and turnips. Make sure to keep seeds and seedlings consistently moist.
* Plant potatoes.
Contact Us
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Food in My Back Yard (FIMBY) Series
Lessons learned during a year of edible gardening
WINTER
Is edible gardening possible indoors?
Hints for choosing tomato seeds
Why winter is the perfect time to plant fruit trees
When to plant? Consider staggering your transplants
How to squeeze more food into less space
Plant a fruit tree now -- for later
Win the weed war by tackling them in winter
Tips for planting bare-root trees, shrubs and vegetables
Time to give vegetable seedlings some more space
Ways to win the fight against weeds
FALL
Dec. 16: Add asparagus to your edible garden
Dec. 9: Soggy soil and what to do about it
Dec. 2: Plant artichokes now; enjoy for years to come
Nov. 25: It's late November, and your peach tree needs spraying
Nov. 18: What to do with all those fallen leaves?
Nov. 11: Prepare now for colder weather in the edible garden
Nov. 4: Plant a pea patch for you and your garden
Oct. 27: As citrus season begins, advice for backyard growers
Oct. 20: Change is in the autumn air
Oct. 13: We don't talk (enough) about beets
Oct. 6: Fava beans do double duty
Sept. 30: Seeds or transplants for cool-season veggies?
Sept. 23: How to prolong the fall tomato harvest
SUMMER
Sept. 16: Time to shut it down?
Sept. 9: How to get the most out of your pumpkin patch
Sept. 2: Summer-to-fall transition time for evaluation, planning
Aug. 26: To pick or not to pick those tomatoes?
Aug. 19: Put worms to work for you
Aug. 12: Grow food while saving water
Aug. 5: Enhance your food with edible flowers
July 29: Why won't my tomatoes turn red?
July 22: A squash plant has mosaic virus, and it's not pretty
July 15: Does this plant need water?
July 8: Tear out that sad plant or baby it? Midsummer decisions
July 1: How to grow summer salad greens
June 24: Weird stuff that's perfectly normal
SPRING
June 17: Help pollinators help your garden
June 10: Battling early-season tomato pests
June 3: Make your own compost
May 27: Where are the bees when you need them?
May 20: How to help tomatoes thrive on hot days
May 13: Your plants can tell you more than any calendar can
May 6: Maintain soil moisture with mulch for garden success
April 29: What's (already) wrong with my tomato plants?
April 22: Should you stock up on fertilizer? (Yes!)
April 15: Grow culinary herbs in containers
April 8: When to plant summer vegetables
April 1: Don't be fooled by these garden myths
March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth
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