August Tips & Events for Santa Clara County

“Now summer is in flower and nature’s hum is never silent round her sultry bloom.”

~ John Clare
 
Monthly Tips

Quiz

These plants all share a common issue. Do you know what it is? 

Photo credits: Utah State University Extension, UC Statewide IPM Project, University of Maryland Extension
A four-square collage showing a tomato - bean leaves - and a green pepper with discolored white or brown areas - and a slender light brown tree trunk with peeling bark 
 

Mark Your Calendar for the Fall Garden Fair 

Our Fall Garden Fair, part of Martial Cottle Park’s Fall Festival, takes place on Saturday, October 11. There will be talks, information booths, a plant sale, and more.


If you wish to start your fall garden earlier, we will sell cool season vegetable seedlings as part of our regular third Saturday sale on September 20.

 

Fire-Safe Landscaping Is for Everyone
overhead view of a suburban house showing 5-foot - 30-foot - and 100-foot spacing

Even if you don’t live in Santa Clara County’s Wildland Urban Interface, landscaping with fire safety in mind is a smart move. Creating defensible space—especially in the first five feet around your home—can dramatically improve your home’s chances in a fire. Start by removing dead or dry vegetation, using non-flammable hardscaping, and relocating flammable objects. Then, work outward to 30 feet, reducing fuel risks and pruning regularly. You may not have acres to manage, but regular cleanup and thoughtful planting can provide peace of mind—and protection—when it matters most.


Photo credit: CalFire
Defensible Space Zones
 

Powdery Mildew—a Fungal Foe
Powdery mildew on melon leaves

Do you see a white, powdery film on your squash, cucumber, melon, or pumpkin leaves? It is likely powdery mildew, a wind-borne fungus that loves our warm, dry summers. It causes the leaves to shrivel up and eventually the whole plant will die. There is no cure, but there are some environmentally friendly things you can do. Spraying the leaves with water in the morning will wash away spores and slow the fungus down. Consider removing badly infected plants to make space in your garden for fall vegetables. Next spring, choose powdery mildew-resistant varieties and be sure to plant them in full sun.


Photo: Powdery mildew on melon leaves, Jack Kelly Clark, UC
Powdery Mildew
 
A photo collage showing - crumpled distorted green leaves - a leaf with small black feces and stippling - green onion leaves with yellow markings - and long red peppers covered with discolored spots

Photo credits: [1-3] Jack Kelly Clark; [4] Aziz Baameur
Quick Tips on Thrips

Signs of Thrips

Summer vegetables love warm weather. So do thrips, a garden pest that thrives in hot, dry conditions. Thrips are tiny sucking insects that cause stippled damage on leaves and fruits. There are many species and host plants. Signs of thrips in the garden are easy to spot, as shown in the numbered photos:


  1. Distorted leaves caused by thrips feeding on young leaves and buds
  2. White scars, speckles of black feces, and a western flower thrips on a leaf
  3. Lesions of  onion thrips-transmitted iris yellow spot virus
  4. Distorted peppers (on the left) infected with tomato spotted wilt virus transmitted by thrips
 

Citrus Pruning

Unlike other fruit trees, citrus does not need to be pruned to be productive. You might still consider pruning to suit your preferences and to keep the tree size manageable. Do heavier pruning just before bloom or just after fruit. You can do light pruning anytime, although it’s best to do it when there’s no chance of frost, to protect tender new growth. Remove dead and diseased wood, vertical water sprouts, and suckers growing from below the graft union. Pruning crossing branches will help keep the tree center somewhat open. Trim lower branches so they don’t touch the ground.
Using hand pruners to trim deadwood in a citrus tree

Photo credit: Allen Buchinski
Pruning Citrus
 
Head of broccoli surrounded by its leaves

Photo credit: jsbaw7160, Pixabay
Vegetables

Start Winter Vegetable Seeds in August 

If you like growing your own transplants from seed, August is the time to start winter vegetables like broccoli, cauliflower, beets, and more. They take 4–6 weeks to grow from seed to garden-ready transplants. Lettuce, bok choy, chard, and some others are faster and can be ready in 3–4 weeks. Use the times listed in the final column of our Vegetable Planting Chart to calculate when to start seeds for different crops. Plan to transplant seedlings in September to early October, while the ground is still warm enough for them to get a good start before cold weather.
 

Quiz Answer: Sunscald and Sunburn

Plants, like people, can suffer sunburn in the hot August sun. These plants all exhibit sunscald or sunburn, which can result in white or leathery spots on tomatoes or peppers, brown spots on leaves, and peeling bark on young trees. How to protect them? Provide shade cloths during the hottest part of the day. Avoid heavy pruning that leaves fruits exposed. Keep plants well-watered during extreme heat and use mulch to retain moisture and reduce heat stress. For young trees, paint their trunks with diluted white latex paint. The good news: you can still eat fruits with sunscald by cutting out the affected areas.
Shade cloth covering tall tomato plants

Photo: Shade cloth covering tall tomato plants, by Barbara Krause
Sunscald
Sunburn
 

More August Tips and To-Dos

For more gardening tips and to-dos, visit the monthly tips archive on our website. It is perfect for browsing, and while you may recognize some of the content, you’re sure to find something new. It starts with to-dos for the month, just the thing to review before heading out to your garden.
More Tips and To-Dos
 
 
 

Upcoming Events

Our monthly Plant Clinic Online is an opportunity to chat with a Master Gardener via Zoom to diagnose a plant problem. You can also listen and learn while other people ask questions. It takes place on the second Tuesday of the month (August 12) from 7 to 8:30 pm. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required.


PADG Get a Head Start on Your Fall Garden, Saturday, August 2, 10:00 am–11:15 am, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


PADG Open Garden Saturdays, August 2, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


MRDG Starting Your Cool Season Garden, Saturday, August 9, 10:00 am–noon, McClellan Ranch Preserve, Community Garden Area, 22221 McClellan Road, Cupertino


PADG Open Garden Saturdays, August 9, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Time to Start Planning Your Cool Season Vegetable Garden, Saturday, August 9, 10:30 am–11:45 am, Willow Glen Branch Library, 1157 Minnesota Avenue, San Jose


STDG Planning Your Cool Season Vegetable Garden, Saturday, August 9, 1:00–3:00 pm, Sunnyvale Teaching and Demonstration Garden, 433 Charles Street, Sunnyvale


Top 10 Habits of Successful Gardeners, August 12, 6:30–7:30 pm, Online


It’s Time to Plan for Your Cool Season Veggie Garden, Tuesday, August 12, 7:00–8:30 pm, Saratoga Library, 13650 Saratoga Avenue, Saratoga


Plant Clinic Online, Tuesday, August 12, 7:00–8:30 pm, Online


Planning a Simple Native Garden for Beginners, Thursday, August 14, 5:30–6:30 pm, San Jose Public Library - Rose Garden Branch, 1580 Naglee Avenue, San Jose


MCP California Native Plant Sale, Saturday, August 16, 9:00 am–noon, Martial Cottle Park, 5283 Snell Avenue, San Jose


PADG Open Garden Saturdays, August 16, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


10 Top Habits of Successful Gardeners, Saturday, August 16, 11:00 am–12:30 pm, Milpitas Library, 160 North Main Street, Milpitas


Lawns: Choices for Turfgrasses, Groundcovers and Meadow Grasses, Sunday, August 17, 1:30–2:30 pm, Rinconada Library, 1213 Newell Road, Palo Alto


Managing Invasive Plants, Thursday, August 21, noon–1:00 pm, Online


PADG Open Garden Saturdays, August 23, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Shrubs and Small Trees to Plant in Fall, Wednesday, August 27, 6:00–7:00 pm, Morgan Hill Library, 660 W. Main Avenue, Morgan Hill


PADG Open Garden Saturdays, August 30, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto


Starting Your Cool Season Garden, Saturday, August 30, 11:00 am–12:30 pm, Tully Community Branch Library, 880 Tully Road, San Jose


Seedy Saturday Seed Swap, Saturday, August 30, noon–1:30 pm, Sunnyvale Public Library, 665 W Olive Avenue, Sunnyvale


PADG Open Garden Saturdays, September 6, 10:00 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto
Check our calendar for the latest schedule of events. Videos of many past presentations are also available.
 

About Us

University of California Master Gardener volunteers promote sustainable gardening practices and provide research-based horticultural information to home gardeners. Visit our website for more information including:


Have a gardening question? Ask us. We’re here to help!
Connect With Us
Facebook  Instagram  Youtube  
 
 

University of California Cooperative Extension | 1553 Berger Drive, Bldg. 1 | San Jose, CA 95112 US

Unsubscribe | Update Profile | Our Privacy Policy | Constant Contact Data Notice