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Elinor Teague

Welcome Elinor Teague

Elinor Teague
A note from Elinor Teague to the readers:  After writing gardening columns for the Fresno Bee for 18 years, it is a pleasure to be able to continue to offer readers gardening advice and tips here on the Fresno County Master Gardeners’ website. 

Readers’ questions and comments are always welcome.  Call the Fresno County Master Gardeners helpline (559) 241-7534 with your questions or bring samples into the Master Gardener office at UCCE office at 550 E. Shaw Ave. in Fresno, M-F, 9-12.

June 2020 Master Gardener website column

June 2020 Master Gardener website column

We had our first truly hot spell of the late spring/early summer growing season this last week of May.  Even well-irrigated plants will have suffered the effects of high temperatures.  New transplants and seedlings will have been most affected; plants with established roots systems will have shown less severe signs of heat stress or maybe none at all.  

When daytime temperatures suddenly rise above 90 degrees and night temps remain at 60 degrees or above in late spring as is common here in the Central San Joaquin Valley, plants are unable to adjust quickly to the change in temperature.   The sudden onset of intense heat can severely damage or kill vulnerable plants.  Pansies, spring-blooming bulb flowers, peas and sweet peas are very susceptible to high temperatures and die quickly.

Some of the symptoms of heat stress and drought stress are similar (wilting leaves, brown tips on leaves), but there are symptoms that are specific to heat stress.

              On hot days, the leaves on many tender-leafed plants will wilt.  If the soil contains adequate moisture, the wilting is temporary and the leaves will recover  overnight.  The leaves on well-watered cucurbits including squashes, melons and cucumbers regularly wilt during the day in summer.  It’s normal for these plants.  In the hot sun, moisture transpires rapidly from their large leaf surfaces but the wilting disappears as temperatures cool in the evening. To avoid overwatering cucurbits, check soil moisture levels before irrigating. 

              Many trees including citrus will drop leaves during hot spells as a means to conserve water in the tree; it’s a survival mechanism.  Leaves make food for trees (and provide precious shade).  That’s why it’s so important to deep irrigate all trees regularly in summer.  A good practice is to deep irrigate trees in summer when the top three to four inches of soil is dry which is generally about once a week or more often during the hottest spells.

              Blossom drop during the first hot spell is common on many vegetables including tomatoes, cucumbers and beans.  Eggplants and peppers tolerate higher heat and hold their flowers better than other vegetables.  Tomatoes, beans and cucumbers will begin to set new flowers and fruit again in late August as nights grow longer and cooler. New leaves on many plants will be smaller after a hot spell and flower petals may be thinner.  Flower fragrance is also adversely affected by high temperatures.

              Bolting or flower set occurs on cool-season crops such as broccoli, chard and spinach in late spring in our climate.  Bolting makes leaves taste bitter. To lengthen the growing time of cool-season crops look for seeds or transplants of varieties that are labelled as ‘slow-to-bolt’,’heat tolerant’ or that have Mediterranean names.   

              To help mitigate damage from heat stress, monitor the weather reports and irrigate before the hot spells arrive.  The soil in container plants dries out extremely quickly in hot weather and the plants will need watering at least once a day.  Consider moving containers into shady spots in the garden when high temperatures are predicted.   



Read Elinor's past articles for this year