Plants are in full battle mode against the heat

Tomato plants at a standstill? Raspberries not setting berries well? Some of your ornamentals getting sunburned leaves?

Besides all this, you may be feeling a bit droopy yourself. It's the hot weather. It's what plants do to protect themselves in times of extreme heat. Maybe there's a lesson for gardeners here somewhere.

We tend to forget, I think, that a plant's main purpose is to reproduce itself. We humans have learned that parts of many plants taste good at certain times and stages of the plant's life, and we help ourselves to the leaves, seeds or whatever looks good. If, in doing so, we make it harder for the plant to reproduce, it will continue to try, by producing more seeds. Think peas and beans.

At the very least, it will try to "save itself" for more favorable conditions. Tomatoes will not set new blooms or set fruit when the temperatures reach more than 90 degrees, for example. Mother Nature tells it to hold off until the temperatures modify, so that the fruit, when fully ripe, will contain viable seed. Many other plants will do the same. My fall-bearing raspberries refuse to set fruit right now, although there are plenty of pollinators around.

My July-planted bush beans are doing well, though, as are the cucurbits, but those are heat-lovers. Root crops are growing merrily along, aided by sufficient water. But remember that carrots are biennials — we just steal the roots and eat them during its first year of life, before it has a chance to set seed, so it doesn't have reproduction worries yet.

Another self-protective technique of some plants is wilting in the afternoon sun to conserve water. Depending on the kind of leaves a plant has, it may show some leaf-curling, as well. Tomatoes are good at this. It tempts us to over-water, however, so, as I mentioned last week, be sure to check the soil before adding water. If the plant revives overnight and is no longer wilted in the morning, it is probably OK in the water department.

Sunburn of leaves and fruit is not self-protective in the same way as other means mentioned here. We may need to give a little first aid. My dahlias in pots were unhappy with the heat, and leaves were sunburning. So, I've pulled the pots away from their front porch showplace, and put them where they will get plenty of light, but no direct sun, until this hot spell passes. They are grateful.

People frequently ask about pruning tomato leaves. This is something I rarely do. The fruit does not need the sun to shine on it to ripen, and spells of hot weather such as this one will often sunburn tomatoes, leaving tough, tan patches on an otherwise good tomato. Leaves on fruit-bearing plants are protectors, so I like to leave them in place.

I've put lightweight Remay over my cucumbers, keeping it high enough over the plants so that the bees can still get in and find the blossoms. Maybe the bees will appreciate a little shade, too. I'll remove it when temperatures moderate.

What life lessons can we, as gardeners learn here? Remember to take in enough water so you don't get droopy and wilted. Cover yourself, not with Remay, perhaps, but sunscreen and a big hat.

And pull yourself into the shade, even if there is yard work to do. Save yourself — this, too, will pass.

Carol Oneal is a past president of the OSU Jackson County Master Gardeners Association. Email her at

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