Farmers Weekly Review

Even people who enjoy summer weather have been wishing these extremely searing temps and humidity would ease up a bit.

I know I’m all too transparent that summer is my least favorite season. But did you know that most plants don’t like it this hot, either? And they do more poorly the hotter it gets?

Many gardeners think the hotter it is, the better and faster the produce. But the reality is that heat, especially when accompanied by drought, causes plants to conserve to survive. And reproducing is put on hold until conditions are more favorable. Reproduction is the part we eat — the fruits of our plants labor of love.

To start, let’s talk pollination. It is true that insects aren’t so crazy about cold weather. Being they are cold-blooded organisms and don’t have the ability to regulate their own temperature, they literally are the temperature around them — cold or hot.

You know how the weather service sends out endless messages telling us to take it easy, move less, stay in the shade, don’t work out when there is a heat advisory?

Well nature does it one better, whether it is bees, your dogs, or my cats, that squirrel splooting all stretched out (yes, that is the official name of squirrels stretched all the way out arms and legs stretched), nature has animals and plants hardwired in their DNA what to do to conserve and preserve with different strategies in many types of adverse conditions.

Whether it is through the slow evolutionary changes over millennia, or today’s modern Agri scientist in a genetics lab working to make plants more tolerant of heat and drought, the ability to adapt to a changing environment is key to survival.

One of my graduate school professors asked us, if plants could do anything that they can’t do now, what would it be? The answer, to have the ability to move. But for the most part, they can’t. But bees can.

And too hot, too rainy, too windy, too pesticide-y, and bees stay home. Pair less pollinator activity with the plant’s need to conserve energy, and you will see changes out there in the vegetable patch.

For the cucurbit crops (the zukes, cukes, melon, gourd family) which have separate male and female flowers, three hot weather issues can arise:

Temperature affects which blossoms the plants produce. When it is over 90 degrees, more male blossoms are produced than female. That might be great if your goal is to harvest squash blossoms to fill with cream cheese or deep fry. But nothing if you want the fruit. All boys and no girls makes for no fruit.

Another common call I get, particularly with pumpkins, is that gardeners think they have overwatered their crops in response to the hot temps and drought, because they find many small pumpkin fruit that appear soft, discolored, and rotted still attached to the vine.

Fungus? Bacteria? Overwatering? No. Poor pollination.

But the most common question I receive, particularly on cucumbers, is why one end is shriveled and didn’t fill out, or why is my cucumber look like it is doing a backbend. Poor pollination.

Even the queen of the vegetable garden — the home-grown tomato –can’t escape being affected by extremely high temps and the often-corresponding drought in several ways.

Did you know that tomato flower pollen availability is about 50 hours per flower? Thankfully, tomatoes produce copious flowers, because that is a small window of opportunity.

Unfortunately, hot weather causes many vegetable and flower buds of all kinds to dry up and abort (fall off) early. Expending too much energy on fruit/seed production could cause enough energy loss that the plant suffers, so it cuts its losses ahead of time by dropping those flowers.

The main impact of the hot weather to tomatoes is to the fruit itself. Last year, I had dozens of callers asking why their tomato plants were absolutely dripping with large numbers of tomatoes — but they refused to turn red. And they just sat there.

On strike? Nope. It is all science … and hot weather.

The carotenoid pigment that makes tomatoes a cancer fighter, lycopene, is also responsible for the red/orange coloring of the tomato. Above 82 degrees, lycopene decreases in production, and ceases if it is too hot. Hence, green tomatoes.

Another common tomato fruit issue — that melanoma-looking black ick on the bottom of tomatoes (and sometimes peppers) that is a predominant problem in hot dry years is blossom end rot.

Although the name may be misleading as rot often causes thoughts of mold and fungus, in this case it is not. It is just a physiological response to a fluctuation of calcium into the plant. But we are the King of Calcium here in the Will, limestone as far as the eye can see and the backhoe can dig.

There is plenty of calcium in our soils, but with heat and drought, even when we try to keep the soil moisture even, fluctuations in calcium uptake causing the discoloration/malformation.

If you have this problem often, you might want to consider purchasing the tomato variety, Jetstar, that has high resistance to blossom end rot. Also research indicates the blossom end rot preventer sprays are ineffective. When the weather moderates, the issue goes away. Pull any green tomatoes with blossom end rot, the red ones are perfectly safe to eat (as long as your family doesn’t see the part you cut off and threw in the compost).

Two other fruit issues in searing heat are just like when I am out in the sun too long — -sunburn — called sunscald in plants. Bleached or dark sunken blister areas on peppers is common.

And I might get burnt shoulders, but tomatoes get yellow shoulders where the tops of the fruit take on a yellow cast and are often hard.

So, what is a gardener to do? The best they can. Good cultural care. Healthy people and plants more easily tolerate duress.

Water deeply, slowly, and as early as you can. Mulch everything. Pots included. I did a non-scientific study in my own yard and at my projects. Putting a thin layer (one chip thick) on the surface of every container, cut my need to water by 50 to 70%.

As I am writing this column, I glance at the calendar — exactly six months till Christmas. And I will be wondering how soon I can start planting.

I absolutely love the Midwest!