Park Seed Garden Journal: Zucchini Seedling Growing Upside Down

Yesterday evening, when I got home from work, I went to check on the zucchini in my Park Seed Bio Dome. These seedlings have grown very quickly, and most were promptly moved outdoors where they could stretch their legs. The last few needed a couple more days under the protection of the bio-dome, and I had one that, until yesterday, had shown very little activity. But, when I got home I found this...

I was very excited at how odd it looked, and knew immediately that I had inadvertently planted it upside down. I brought the picture to Park Seed to share with co-workers, and it was forwarded to a horticulturist. He thought it was pretty neat, and he gave a helpful explanation of what exactly was going on.

I've attached his emailed response below.

Ain't Plants Fascinating?

The radicle (root) is the first thing to emerge from a germinating seed. On a squash seed. the radicle grows from the pointed end and, if the seed is placed in the growing medium with this point up, then the roots emerge in what we consider an upside down state. Plant roots respond to gravity by growing downward (positive geotropism) so if they come up this way they will just naturally respond by growling downward. At the same time, the shoots (cotyledons) are emerging underneath the growing medium and they respond to gravity in a negative manner (negative geotropism) and begin to grow upward.

Even if Thomas had not helped , the roots and shoots would have eventually reversed themselves. This condition may happen in the garden quite often but since the seed are covered we are not aware of it. It may just take a day or two longer for the seed to emerge and we never know the difference. It's something that Nature has evolved over the years to ensure the roots grow down into the moist soil and that the shoots grow up and toward the sun (survival of the plant).

Thanks for sharing the photo.

To clarify what he meant when he said that I “helped,” I dug out the entire seedling, roots and all, with my finger, flipped it around and shoved it back into the Bio Dome growing sponge. In this context, the word “help” is fairly subjective as the ultimate fate of this young seedling is still undetermined. It was well-developed but slightly discolored-- hopefully that will change now that it can get some light.

Thomas
Park Seed Company