Powdery Mildew

How do I have powdery mildew already? In California?! This photo is from my squash plant. Both the zucchini and winter squash have it on a couple of leaves.

I thought powdery mildew was supposed to happen in humid environments, and the Bay Area is anything but humid… hmmm… I have some things to learn about powdery mildew…

Powdery mildew is a disease caused by several different types of fungi (437 different species within the order Erysiphales). The spores or conidia of the fungi are carried by the wind to a host plant. According to the Penn Extension, ideal conditions for powdery mildew are high humidity at night and low humidity during the day with daytime temps of 70-80 degrees. Additionally, the University of California Master Gardener’s website says that placing plants in full sun can help prevent or kill the fungus that is causing powdery mildew, since powdery mildew fungi don’t like really intense heat.

From the Ohio State Extension

Here in Palo Alto, we have low humidity during the day and 70-80 describes pretty much every summer day here. I occasionally water in the evening, after I get home from work and see that the garden looks a little dry, which may make for relatively humid local conditions during the night. The squash plants are in the most sunny spot we could find, but there are several trees in the area, so it is mostly shaded in the afternoon. Overall, not ideal for my squash plants, but pretty ideal for powdery mildew fungi.

Fortunately, it’s a very mild case at this point, so I’m not going to bother trying to treat it, but it’s a good lesson for me to water in the morning rather than at night. Ideally, I would have a drip system set up on a timer, but those are dreams for a garden a few years from now.

One other thing I learned about powdery mildew is that the fungi are obligate parasites, which means they need a living host to survive. Therefore, (apparently) it’s ok to throw powdery mildew-infested plants in the compost pile, since when the plant dies, so does the fungus. Huh. Is this really true?

The Fruit Trees of Stanford

Did you know that prior to becoming “Silicon Valley” the Bay Area used to be called “The Valley of Heart’s Delight?” Apparently, it got this name because of all of the fruit orchards in the area. In the 1930s, San Jose, which is just south of Palo Alto, was the world’s largest cannery and dried fruit packing center. El Camino Real (a major highway through Palo Alto that connects San Diego with San Francisco) used to a a dirt road line with orchard trees between Palo Alto and San Jose.

Although there aren’t many orchards left in the immediate area, fruit trees are not infrequently seen. The plum and peach season seems to have just ended, and we’re starting to get into pears and apples. Fall is coming! But some citrus (like lemons) are also ripe, which confuses me.

There’s a map of Stanford’s campus that identifies all of the fruit trees in the area. When Nate visited me, we tried to find as many as we could.

At firs we weren’t having much luck…the campus was pretty, but the first few fruit trees we tried to find weren’t where the map said they would be.

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Pear Harvest

Last Sunday, I volunteered for Village Harvest again. This time we were harvesting pears, and it was in Los Gatos hills. The Los Gatos hills are about 40 minutes from me. I drove down some narrow and windy, but scenic roads to get there.

I took this photo while pulled off to the side of the road, trying to figure out directions.

The pear trees we were harvesting from were on four adjacent residential properties. My guess is that this area was once a large pear orchard, but over the years, the land was broken up and sold off. Here are some surreptitious photos I took during the harvest to give you a sense of the place.

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The Fall Garden Seeds Are Already Sprouting!

Watching plants grow never ceases to amaze me. Some of the plants in the fall garden that I planted last Sunday (August 9th) are already coming up! These photos below were from Thursday (August 13th).

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Planting a Fall Garden

A couple of weeks ago, I dug up a 3×3 square of dirt in the backyard to plant zucchini and winter squash. The squash are doing well, which has increased my confidence in planting things in the dirt here.

I have some seeds that I brought down from Seattle, and there was a bit more space around where I planted the squash, so I decided to put it to good use.

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Plant Starts from Dr. Kong

One of my attendings gave me some plant starts — rooted cutting, and small seedlings. Her mother (who is in her 80s) does a lot of gardening. She plants everything from seed and always has a lot of extra seedlings.

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