Monday, July 20, 2009
Marigolds to "Attract" Pollinators?
All of my relatives seem to believe this odd gardening concept. Firstly, they're growing mostly tomatoes, squash, corn, radishes, onions, and peppers. And to attract pollinators they were told to plant a flat of marigolds because "pollinators are attracted to the color." Considering I'm the beekeeper of the family, with a pollinator garden, I wondered why the hell they didn't ask me.
The concept sounds simple enough. Bees, flies and such see bright colors and go see what's going on. They buzz down and find useless marigolds with a 250 flower petal count making the reproductive parts useless, and supposidly go to the flowers on your crops instead. I'm exaggerating on how many flower petals marigolds have but they're just so useless. Like many roses bred to be pretty they have way to many flower petals for the most of the flowers to be any good. They're bred for color, fragrance, or sterility.
If this were such a renown method of getting good pollination, then why don't farmers just plant marigolds as a year round cover crop? The answer actually lies in how flowers work.
Insects see differently than humans do. They see more colors in the ultraviolet spectrum. So when we look at a flower, such as the mint plant above, we see a blue violet color with a dark patch in the middle. But to insects, that bright patch in the middle of the flower is actually glowing intensely.
What looks like an ordinary yellow Black Eye'd Susan actually has a lot more going on than just the yellow. See here.
The reason why farmers don't plant a flowering cover crops is because they have plenty of flowers doing the job for them. Their plants were grown for fruit production, not to have frilly flowers.
Having some knowledge about what you're growing can also be key. Going back to what my relatives are growing for a moment: tomatoes, corn, and peppers are all wind pollinating. You'll have good pollination as long as you have 6 or so plants (at least 10 in the case of corn) growing within a few feet of one another. You may still see bees pollinating them but it's not necessary. Squash and all Melons should also be planted in bulk. They produce male and female flowers, so the more plants you have the more likely the right sex of flower will be open at the right time. Radishes, and onions don't actually need to pollinate to grow. When they do flower though, they have no trouble getting pollinators to them. They're actually a good honey crop and bees work them happily.
So as long as your garden is large enough with plenty of flowers you shouldn't need any added plants to attract them. If you're going to plant anything I would suggest Liatris or a low growing Sunflower, 4' or less. The colors would be great together as they're both the same height. And they work with the flowers to your main summer crops. They have the added benefit of producing bird seed to help keep the slugs and caterpillars off your plants. Phacelia is also a good annual to choose, but it blooms earlier. I will put this method to practice next year.