Triple-digit temperatures can keep tomatoes from turning full red, says Farmer Fred
Jetsetter tomato seems stuck on orange instead of turning full red. Blame the heat. Debbie Arrington
It seems counterintuitive; instead of ripening faster as days get hotter, tomatoes seem to slow down.
A lot of Sacramento-area gardeners are experiencing that phenomenon firsthand as they watch their tomatoes very very very slowly change from pinkish to full red.
Farmer Fred Hoffman, lifetime master gardener and award-winning radio host/podcaster, made that point in his weekly newsletter and “Garden Basics” podcast.
“Many area gardeners are wondering about the lack of color of their tomatoes now, in late summer,” Hoffman said. “Blame the triple-digit heat spikes that have occurred coast to coast for the slowdown this summer.”
According to university research, a couple of factors are in play. In late summer, tomato vines may have fewer leaves. Less foliage means less photosynthesis, which means less energy and slower growth for the plant. Without that boost of energy, its green tomatoes take longer to grow to size and ripen.
In addition, red pigments can’t form properly in triple-digit heat. Yellow and orange pigments seem to do OK, which leads to ripe tomatoes with splotches. They’re fine to eat, although not classically perfect.
Another factor: Soil temperature. If tomato roots stay over 80 degrees, fruit ripening is affected, too. (This is a problem in container-grown tomatoes.)
If your tomatoes seem to be taking forever to ripen, the solution is easy: Pick them. Then let them ripen in a dark space indoors (such as in a box on the kitchen counter). Their flavor may not be as intense as if vine-ripened, but they’ll be red and juicy – and finally ready to eat.
“Light conditions have very little to do with ripening," report Cornell University researchers. “Tomatoes do not require light to ripen and in fact, fruit exposed to direct sunlight will heat to levels that inhibit pigment synthesis. If temperatures remain high outdoors, these picked fruit will ripen more quickly, perhaps by as much as five days.”
Hoffman also has great advice this week on worms (or to be more specific, caterpillars) that eat tomatoes, and how to tell the culprits apart.
Listen to Farmer Fred’s podcast and newsletter here: https://gardenbasics.substack.com/.
Check out his "Get Growing" website here: http://www.farmerfred.com/
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Flowers in My Back Yard Series
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 June 7
Afternoon highs are expected to be back in the mid 90s by midweek, then edging towards triple digits. Plan your planting and garden activities accordingly.
* Remember to water early.
* It’s not too late to transplant tomatoes, peppers, eggplant or other summer favorites. Make sure they stay hydrated.
* From seed, plant corn, melons, pumpkins, radishes, squash and sunflowers.
* Plant basil to go with your tomatoes.
* 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.
* 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.
* Cut back fruit-bearing canes on berries.
* 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 off dead flowers from rose bushes 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.
* Pinch back chrysanthemums for bushier plants with many more flowers in September.
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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