HOrT COCO-UC Master Gardener Program of Contra Costa

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Crape Myrtle with powdery mildew

Powdery Mildew on Crape Myrtles

September 1, 2025
By Help Desk Team
Note: this is a rerun of an article originally printed in the Contra Costa Times. Q: I have a crape myrtle and every year it is covered in a whitish powder. I have been told it is powdery mildew, but I don't know how to control it.A: Powdery mildew is a plant disease caused by a fungus, Erysiphe…
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Garden dahlia flowers

Late-Summer Dahlia Problems - What's up?

August 20, 2025
By Dawn A Kooyumjian
A favorite summer flower is dahlias – little ones, big ones and even really big ones as is Dahlia imperialis growing from 8 to 12 feet tall.Were your dahlias looking fantastic earlier this summer, full of stunning blooms and healthy leaves but now they are starting to look a little tired? Here is a short…
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Shelf of fertilizers

The ABCs of Fertilizer

August 3, 2025
By Help Desk Team
Understanding the ins and outs of fertilizing your garden can sometimes feel overwhelming. The shelves of colorful products at the local shop, sometimes with confusing labels, promise magical results. By keeping in mind some basic facts about fertilizers and fertilizing, you may approach the task with much…
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Tomato blossoms

Tomatoes Not Producing

July 21, 2025
By Help Desk Team
Note: This article was previously published in 2018. We are rerunning it because we are noticing this happening in many gardens right now.Client's Request: Why no tomatoes? Starting to get lots of flowers but almost NO tomatoes? Plants look very healthy. I live in central Contra Costa County.MGCC Help Desk…
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Veggie garden

How to Know When Garden Vegetables Are Ready to Harvest

July 7, 2025
By Help Desk Team
  The long-awaited summer harvest time is approaching, and our mouths are watering in anticipation of those first juicy tomatoes and sweet, crisp cucumbers. But it is not always obvious when some fruits and vegetables are at their peak and ready to pick. Here are some tips for knowing when to…
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