Bay Area gardens face a range of temperatures from inland to coastal

As we continue through summer, some of us are living where a cold ocean wind bears fog day in and day out while others, who live more inland, are baking in hot sun. Both conditions can reduce production of summer crops like tomatoes, beans or eggplant. And both microclimates offer special opportunities to grow adapted crops.

First, problems caused by cool summers: The cold nights of the coastal microclimate can prevent tomatoes from setting fruit. If nights fall below 55 degrees Fahrenheit, possible on any night of the year, blossoms will drop unfertilized, leaving only their stems to taunt us with what might have been. Peppers and eggplant are even fussier, needing temperatures to stay above 60 degrees for fruit to set. However, beans can set at temperatures as low as 50 degrees.

Tomatoes that do set fruit in cool, damp weather can also show “catfacing.” This deformity, consisting of brown lines and folds at the bottom, blossom end, of a tomato are thought to be caused by adherence of the blossom to the young fruit. Some varieties are more susceptible than others, with many recent hybrids having been selected to avoid the problem.

Three crops that need bees for pollination are squash, pumpkin and cucumbers. All three will set fruit better where sunshine and protection from wind will encourage bees to fly. (Once pollinated, cucumbers will need more heat to set fruit than squash or pumpkin, but will do so in areas of moderate warmth.)

Next, heat. While we may think of summer crops as liking heat, the more the merrier, this is not the case. The ideal temperature for tomatoes is between 75 and 85 degrees, with blossom drop starting at 90 or 95 degrees. High heat can cause tomatoes that do set to ripen to be pink or orange-y instead of red, or even to be red outside but green inside. Temperatures over 90 can also reduce fruit set of peppers, eggplants and beans. Providing a little shade in the heat of the day can reduce such problems somewhat. Cooler nights, such as those inregions with some coastal influence, are also a help when gardens experience high daytime temperatures.

A problem that can happen even near the coast whenever there are a few days of unusually sunny weather is sunscald. Burned areas appear on the southwest sides of tomatoes or other fruits, even tree fruits. Good leaf cover protects fruit. Choose tomato varieties with broad, plentiful leaves and beware of overpruning your plants. Select diseaseresistant varieties and examine plants carefully for insects, such as hornworms, that can defoliate a plant.

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