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Garden Guru: Time for The Talk -- birds and bees

By John Porter

CHARLESTON, W.Va. -- As recently as last week, you have read my laments about the abundance of summer rains causing diseases to run rampant in our gardens. Let's face it, it has been a pretty terrible year for most of the garden. Disease problems aside, it is becoming apparent that there are other issues that the rain and clouds are causing.

A lot of early problems in the garden and landscape this year had to do with poor root growth because of heavy moisture in the soil. Excess soil moisture can kill the root hairs that are responsible for much of the water and nutrient uptake in plants, resulting in nutrient deficiencies and even a reduced ability to take up water amid all the rain.

Tomatoes, peppers and other plants waited weeks or months without much growth, as did some trees and shrubs. Some plants finally started growing and others did not. I finally gave up on my 1-foot-tall pepper plants that were bent over with three peppers each.

Another problem in the vegetable garden is becoming increasingly apparent and troubling to those I talk to: lack of fruit production and development.

Now when I say "fruit," I'm talking about anything that arises from a flower and contains seeds, even if we call it a vegetable. Cucumbers and squash, tomatoes and peppers, and even corn and beans are all fruits. The problem is one of pollination -- or lack thereof. So now we need to have the talk, the one about the birds and the bees. Well, the bees anyway.

Crops that are self-pollinated aren't having as much trouble. Beans, peppers and tomatoes, along with their relatives, are all self-fertile. They do not need pollinators to have a crop; in fact, bean and tomato flowers are built to keep bees out to ensure self-pollination.

The plants that have had the most trouble this year are the ones that rely on bees for pollination, most notably the cucurbits -- cucumbers, squash, melons and the like. These plants all have separate male and female flowers on each plant, and pollinators (bees) are required to carry the pollen from the male to the female flower. Bees do not like dodging raindrops, so when days are rainy, little pollination occurs. Even heavy clouds and overcast skies can keep bees from their pollination duties.

It takes as many as 15 visits from a pollinator to make sure that a cucurbit flower is fully pollinated. Without these visits, the fruit will either not develop, or will have parts that are shrunken and misshapen.

If your cucurbits are showing signs of lack of pollination, you might have to take matters into your own hand. Using a small artist's paintbrush, all you have to do is transfer pollen from the male flower to the female flower. Simple, right?

Well, which is the male flower and which is the female?

The easiest way to tell the difference in flowers is to look at the base. Female flowers will have an ovary at the base that will resemble the finished product, a tiny cucumber, melon or squash. Male flowers are typically smaller and only have a stem at the base. If you look inside the flower, you will also notice that the male flower will have multiple pollen-producing stamens, while the female has only one large pistil in the center.

I've also had complaints about corn not being pollinated this year, and I think that rain is to blame there as well. My most recent case had corn ears that didn't even produce silks. Corn, much like our squash, has separate male and female flowers on one plant. The tassel at the top is the pollen-producing male flower and the female flowers are the ears, with each silk attached to one ovule (egg cell) that will turn into one kernel.

My theory in this case is that the soil moisture damaged the root hairs, and the plant couldn't produce long enough silks to make it out of the ear (it takes a lot of water to produce silks). There is also an issue of pollen. When the tassels are overly wet, they will not release pollen, and constant rain can wash the pollen out of the air and ruin chances of pollination.

Once pollination occurs, it is important that conditions remain conducive to fruit development. Cloudy days reduce the amount of sun that plants receive and reduce sugar production through photosynthesis. Sugar drives the ripening process; so without it, fruit ripening slows and gardeners have to exercise patience. Cool temperatures at night can also slow down plant growth processes, further slowing garden production and frustrating gardeners.

So, if the rain and the doom and the gloom have you fretting over your garden fare, keep in mind there's always next year and things will get better. Of course, I've been telling people that for the past four years, and it hasn't happened yet. It seems like wacky weather and garden maladies are the new norm. Just keep calm and garden on.

John Porter is the WVU Extension Service agent for agriculture and natural resources in Kanawha County. He may be reached at john.porter@mail.wvu.edu or at 304-720-9573. Twitter: @WVUgardenguru.


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