Gardening: Some like it hot, but berries struggle in the heat

OK, folks, here we are in the fourth week of the heat wave. Suffice it to say this is not an ordinary summer. That means our vegetable gardens are not growing as we are used to either. Let’s look at some crops that are being challenged by the heat.

Depending on the variety, I’m seeing a lot of corn patches that are beginning to tassel; that is, producing the male flower at the top of the stalk. This is two weeks early. The tassel will produce pollen that is picked up by the wind and blown through the other corn plants. Lower on the stalk, the corn silk is emerging and catching the windblown pollen. The corn silk is the female flower, and each strand is a hollow tube that the pollen travels down into the ear to form a kernel. When the silk begins to dry, it will be about 21 days before the corn is ready to harvest. Keep corn well-watered and apply one last round of fertilizer.

Tomatoes and peppers are in a conundrum in this heat. Both need night temperatures over 55 degrees to set fruit. We are averaging in the mid-60s which is good. However, when the temperatures get into the mid-90s, the pollen dries and doesn’t stick to the pistil of the flower. In addition, honeybees who move the pollen around are at home trying to keep their hives cool. Even the native pollinators are taking it easy. Hence, we are likely to get spotty sets of fruit. If we get some days in the 80s, we will get some fruit set. When it starts cooling down in mid-August, we are likely to get a solid fruit set for harvest in September. Keep the plants well-watered to prevent brown rot from setting in on the tomato bottoms and do one last fertilization. Don’t trim off foliage as exposed fruits will likely sunburn.

The squash family is loving the heat. Our community garden is already producing wheelbarrows full of yellow zucchini and the winter squash and pumpkin vines are taking over the place. Squash plants have male and female flowers. The male flowers will come out first followed by the female flowers. To identify the female flowers, look for a swelling at the base. Squash are pollinated by bees so are faced with the same problem as the tomatoes and peppers when it gets hot; the bees aren’t flying so fruit set may be spotty. You can take a cotton swab and dust pollen from the male to the female flower if you are impatient.

Our raspberry, blueberry and blackberry crops are struggling. The heat is desiccating the berries as fast as they ripen, and sunburning fruit exposed to the sun. Berries hidden under leaves are faring better but are small. If you pick daily, you might get a decent amount. About all you can do now is keep watering deeply to preserve the new blackberry and raspberry canes and the foliage on the blueberries for next year.

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Pat Munts can be reached at pat@inlandnwgardening.com