April Tips & Events for Santa Clara County
“There is nothing that is comparable to it, as satisfactory or as thrilling, as gathering the vegetables one has grown." — Alice B. Toklas

Spring Garden Market
Sat. April 14, 9–2  Martial Cottle Park, San Jose
Start your summer garden with our Spring Garden Market! Shop our huge variety of tomato , pepper, herb , and  flower seedlings, plus a beautiful array of  succulents . We grow many varieties not available elsewhere, selected for taste, beauty, and performance in our soil and climate.

See our website for more information , including the schedule of talks, additional vendors, and more. Arrive early for best selection.
Heirloom tomatoes
It's Veggie Time
You can start many summer vegetables now from seed or transplant. Consider starting them in small pots and then moving them up to larger pots as they start to grow. This will allow them to get bigger and stronger before you plant them in the ground. Many warm season vegetables such as tomatoes and chiles need warmer soil temperatures before they can go into the ground. Wait until nighttime temperatures are consistently above fifty degrees for the soil to warm up enough for them to grow well. You can plant them outside earlier in containers and slightly earlier in raised beds.

Photo: Pepper seedlings at Martial Cottle Park, by Allen Buchinski
Bud galls on pluot by Susan Casner-Kay
Plum Bud Gall Mite
A new pest has been discovered in our county and is being closely monitored. The tiny Plum Bud Gall Mite causes deformities of buds and other plant parts and can weaken and potentially kill a plant. Galls are abnormal outgrowths of plant tissue and can look like tumors on the plant. The galls are formed by irritation of the plant cells by the feeding or egg-laying behavior of the mites. This particular mite is found on stone fruit trees such as apricot, peach, plum, and pluot. If you think you have found evidence of this pest, please notify the Santa Clara County Department of Agriculture at 408-916-4600.

Photo: Galls caused by plum bud gall mite on pluot, by Susan Casner-Kay
Bay Area Checkerspot butterfly from Calphotos website by Bill Stagnaro with Creative Commons 3.0 License
Butterflies provide beauty in your garden and aid in pollinating your plants. You can provide them with their habitat needs of food, space, and shelter. Planting a variety of colorful flowers will attract them. Native flowers are particularly good for supporting native butterflies with which they have co-evolved, and umbel flower forms act as landing pads. Some good choices are Achillea millefolium (yarrow), Ceanothus (wild lilac), Eriogonum (buckwheat), and Salvia spathacea (Hummingbird sage). If you plant milkweed for the monarchs, make sure to choose a variety native to California. Avoid tropical varieties which can disrupt the monarchs' migration patterns.

Photo: Bay Checkerspot Butterfly from Calphotos website , by Bill Stagnaro ( Creative Commons Share Alike 3.0 License )
White potato tuber from CA Master Gardener Handbook 2nd Edition
Starting with “seed potatoes” from a nursery or mail order catalog, instead of using leftover supermarket potatoes, increases the chances of sprouting and decreases the chances of disease. You can plant small potatoes whole and cut large ones into pieces with at least two eyes each. Plant them in well-drained soil, ideally with compost added. Dig a trench about eight inches deep and place the potatoes about a foot apart. Cover with about four inches of soil. After a couple of weeks, green leaves should appear. When the stems are about eight inches tall, add a few more inches of soil. This process is called hilling. Repeat after a couple more weeks, and perhaps a third time. This will create mounds in which the potatoes will develop. Wait until the plants have blossomed and started to die back before carefully digging up the potatoes. One potato will magically turn into a couple dozen potatoes.

Illustration: Potato tuber, CA Master Gardener Handbook, 2nd Edition
Variety of citrus slices from USDA website
Citrus trees can be planted now. Most do best in sunny spots. Dig a hole the same depth as the root ball and two or three times as wide. Remove from pot and place in the hole, then backfill with the native soil. The soil level at the base of the tree should be slightly higher than the surrounding area to make sure water doesn’t pool around the trunk and cause crown rot later. Water well. You can plant smaller trees in large containers such as half wine barrels. Now that the danger of frost has passed, you can also prune existing citrus trees. Prune to keep them at a manageable size or to increase airflow through the trees which helps reduce pest and disease problems.

Photo: Variety of citrus slices, USDA image library , by Scott Bauer
Visit or subscribe to our blog  for longer articles on seasonal topics
Photo taken at Sunnyvale Library by Tuan Hoang
Upcoming Events
We offer free or low-cost gardening talks, workshops, and courses all over the county, as well as hosting information tables at many community events. Please join us and bring your questions!

Wed, Apr 03, 6:00 p.m.–7:30 p.m.,  Winning the War on Weeds , Los Gatos Library, 100 Villa Ave,  Los Gatos

Sat, Apr 06, 10:30 a.m.–12:00 p.m.,  Succulents for Sunny Areas, and Dividing an Agave , Martial Cottle Park, 5283 Snell Ave,  San Jose

Tue, Apr 09, 7:00 p.m.–8:30 p.m.,  Growing Citrus in Containers , Campbell Library, 77 Harrison Ave,  Campbell

Thu, Apr 11, 7:00 p.m.–8:30 p.m.,  Art and Science of Plant Breeding , Gilroy Grange Hall, 8191 Swanton Lane,  Gilroy

Sat, Apr 13, 9:00 a.m.–2:00 p.m.,  Spring Garden Market - Martial Cottle Park , Martial Cottle Park, 5283 Snell Ave,  San Jose

Thu, Apr 18, 7:00 p.m.–8:30 p.m.,  Incredible Edibles: Cucumber- Melons & Squash! , Palo Alto Rinconada Library, 1213 Newell Rd. Palo Alto 94303,  Palo Alto

Sat, Apr 20, 10:00 a.m.–1:30 p.m.,  South County Spring Garden Market , Guglielmo Winery, 1480 East Main Ave,  Morgan Hill

Sat, Apr 20, 11:00 a.m.–12:00 p.m.,  Attracting California Native Bees and Honey Bees to Your Garden , Martial Cottle Park, 5283 Snell Ave,  San Jose

Sat, Apr 20, 11:30 a.m.–1:00 p.m.,  Low Water Ornamentals From Around the World , Mountain View Library, 585 Franklin Street,  Mountain View

Sat, Apr 20, 1:00 p.m.–3:00 p.m.,  Growing Summer Vegetables , Sunnyvale Teaching Garden, 433 Charles St.,  Sunnyvale

Mon, Apr 22, 7:00 p.m.–8:30 p.m.,  Growing Flowering Plants in Containers , Morgan Hill Library, 60 W. Main Ave,  Morgan Hill

Wed, Apr 24, 6:30 p.m.–8:00 p.m.,  Selecting and Maintaining Fruit Trees in Your Garden , West Valley Library, 1243 San Tomas Aquino Rd,  San Jose

Wed, Apr 24, 7:00 p.m.–8:30 p.m.,  Dragonfruits-Lovely To Look At- Healthy To Eat , Los Altos Library, 13 S. San Antonio Rd,  Los Altos

Mon, Apr 29, 7:00 p.m.–8:30 p.m.,  Plants that Attract Birds- Bees- and Beneficial Insects , Gilroy Library, 350 W. 6th St.,  Gilroy

Sat, May 04, 10:00 a.m.–4:00 p.m.,  Going Native Garden Tour , Santa Clara County, Various Locations

Sun, May 05, 10:00 a.m.–4:00 p.m.,  Going Native Garden Tour , Santa Clara County, Various Locations

Sat, May 11, 3:00 p.m.–4:00 p.m.,  Growing Vegetables in Containers , Willow Glen Public Library, 1157 Minnesota Ave,  San Jose
Visit the UC Master Gardener Program website  for additional information including an up-to-date list of events and classes .

Have a gardening question? Contact our Help Desk (for Santa Clara County residents). Start by reviewing our plant  problem diagnosis tips .
  • Mon-Fri 9:30 a.m.–12:30 p.m., 408-282-3105
  • Fri ONLY 1:00 p.m.–4:00 p.m., 650-329-1356 (Closed Dec. & Jan.)
  • Or send us your question online

The University of California Cooperative Extension (UCCE) Santa Clara County Master Gardener Program volunteers are trained under the auspices of the UCCE. Our mission is to promote sustainable gardening practices by providing up-to-date, research-based horticultural information to home gardeners.

The University of California prohibits discrimination or harassment of any person on the basis of race, color, national origin, religion, sex, gender identity, pregnancy (including childbirth, and medical conditions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related or genetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or status as a covered veteran (covered veterans are special disabled veterans, recently separated veterans, Vietnam era veterans, or any other veterans who served on active duty during a war or in a campaign or expedition for which a campaign badge has been authorized) in any of its programs or activities.

University policy is intended to be consistent with the provisions of applicable State and Federal laws.