What's Wrong with My Zucchini?

One of the most frequent questions on the Vegetable Gardening Forum at GardenWeb goes something like this:

My zucchini started out just fine. They seemed to be growing. Then, out of no where, they started to turn yellow/brown and are rotting on the blossom end. They have enough fertilizer and water. Other than the rotting zucchini, the rest of the plant looks fine. What happened to my zucchini?

Do you recognize this sad little zuke?

Anyone who has grown zucchini has had this happen to them. Don't worry, you are not doing anything wrong. Your sad little zucchini is probably just the result of insufficient pollination.

 Zucchini plants are optimists. The female flowers start to produce zucchini before they are pollinated (really, their ovary is just swelling). At some point, however, if the female flowers are not properly pollinated by a male flower, the zucchini is aborted (botanical terminology, not mine). That is what you are seeing when you look at a mushy yellow little zucchini like the one above.

There are a few things you can do to reduce the chances of this happening. The easiest is to attract more pollinators to the general vicinity of your plant. Bees are the best zucchini pollinators. You may see other insects in your zucchini flowers (e.g. beetles, ants) but nothing gets the job done like a bee. Place plants that attract bees around, or even better in, your garden. For the more adventurous, you may want to create a bee habitat near your garden. Consider building bee blocks for mason bees. If you are really ready to commit, get a top bar hive for honey bees!

A bee block to attract mason bees.

You can also step in and help out mother nature yourself. Skip the bees and hand pollinate zucchini yourself. Remember the best time to do this is early in the morning when the flowers are open.  Try it and let us know how it works for you!