I remember that my squash plants last year had a lot of blooms but produced very little squash. What do you think caused that? MW

We receive quite a few questions like this during the growing season and one of the keys to getting fruits and vegetables is good pollination. Before we answer your question, let’s talk about pollination.

In its most basic definition, pollination occurs when the pollen from the male part of the plant (the anther) moves to the female part of the plant (the pistil). The primary goal of pollination is to produce a fruit that contains and protects the seeds. It’s all about reproduction.

Pollination can happen within an individual plant flower or some plants have separate male and female flowers. Some plants require pollen from the same cultivar, and some require pollen from a different cultivar. The reality is that there are a variety of ways for pollination to happen and it depends on the plant. Let’s talk about that.

Some plants are wind pollinated. Plants in this category would include wheat and corn. These plants are pollinated when the wind blows, blowing pollen from one plant and to another.

Plants in the solanaceous plant group like tomatoes, peppers, and eggplant have what are called “perfect” flowers which means that their flowers contain both male and female flower parts. Because of this they can be pollinated by the wind or by a visiting pollinator insect like a bee. The bee visits the flower to retrieve nectar and while doing so moves the pollen from anther to pistil by their moving around in the flower.

Sometimes the flowers on these solanaceous plants drop without being pollinated. We call this blossom drop and it typically occurs when temperatures are below 70 degrees or above 90 degrees. This is why most of our indeterminate tomato plants tend to stop production during parts of July and August. It’s just too hot for pollination to be accomplished in spite of how many pollinators visit the flower. But if we can keep these plants alive till the weather cools down, fruit production should resume again.

There are some crops that do not require pollination to produce an edible harvest. Plants in this category would include lettuce, spinach, arugula, cabbage, broccoli, cauliflowers, carrots, beets radishes, peas, and beans to name a few. And let’s not forget potatoes.

Just to complicate pollination a little bit further, many fruit trees, such as apples and pears must be pollinated from a separate cultivar. This means that if you plant several apple trees, you need to plant at least two varieties. I feel like some of you just had a light bulb light up above your head.

Now, to your question about squash. Squash is a cucurbit and cucurbits produce flowers that are male and flowers that are female. You can tell the difference because female squash flowers have an ovary below the flower that essentially looks like a very tiny cucumber.

The initial batch of flowers a squash plant will produce tend to be male flowers. Female flowers are added later. This is could be one reason why your squash had flowers but no fruit.

Another potential reason you are not getting any fruit is that the female flowers are not getting pollinated. The primary reason this might happen is that you don’t have a good pollinator population nearby.

One of the best ways to remedy this is to plant flowers around or in your vegetable garden. You sometimes need some bait to attract pollinations, especially in our artificial urban environments.

I have planted flowers around and in my vegetable garden for several years. But I think my best attractors of pollinators are the oregano and basil in my garden. I don’t use a lot of oregano, but it comes back every year and during the summer it tends to be covered with pollinators…similar situation for the basil once it starts to flower.

So, when the pollinators come to my garden for the oregano and basil, they also tend to visit the vegetable flowers in the garden.

There is also the option planting vegetables in your flower garden. I have seen some beautiful gardens that utilize this strategy. There’s really no reason why we would separate them other than convenience or maybe we have always thought of them as separate. But think about mixing it up.

Now, if you are growing crops in a greenhouse that require pollination, you are going to have to take some extra steps. For plants like tomatoes, whose flowers contain both male and female parts, the solution may be as simple as shaking your plants a bit to move the pollen around.

However, if you are growing a plant like squash or cucumber that has separate male and female flowers, you may need to take pollination into your own hands so to speak. To do this, you can get a small paint brush, stick the brush into the male flower to cover it with pollen. Then place that paint brush into the female flower and jiggle it around. It’s not the most elegant solution, but it will work whether you are in a greenhouse or your squash flowers are just not getting pollinated.

The bottom line is that there are a variety of ways plants are pollinated and a healthy, diverse garden may be one of your best strategies for success.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Photo: Todd Johnson: Oklahoma State University Agricultural Communications Services