Growing Family Science Savvy: Windowsill Gardening of Potatoes, Sweet Potatoes and Onions

Growing Family Science Savvy: Windowsill Gardening of Potatoes, Sweet Potatoes and Onions

 

So here's the experiment to consider this month. Let's compare how three root crops grow in windowsill gardening: sweet potatoes, white potatoes, and onions. You'll need glass jars of the Goldilocks size (not too big, not too small...) for the size of the sweet potatoes, white potatoes and onions. Put four tooth picks halfway into the flesh. Put the potatoes and onions into the mouth of a glass jar, one plant per jar. The toothpicks will hold the plant on the rim of the mouth so half the plant is in the jar, and the other is above the jar. Fill the jars with water and add water as needed to keep the level near the rim.

Now you'll get to watch and compare what happens to the three in a sunny windowsill. You will likely get shoots from all three. But the onion will likely give you only one shoot, and it will not be a vine. The two potatoes will likely give you many shoots. The white potato will grow shoots that are called 'vines' but they don't twine. But the sweet potato will grow vines that will run along the sill.

Try cutting several of the white potato vines and the sweet potato vines and placing them in a separate jar of water, with about half of each length of vine in the water, and the other half in the air. Have the growing point of the vine be the end that's out in the air. Also try putting an onion leaf in the water. Watch to see which if any of these grow roots in the water. When the roots are four or five inches long, try transplanting the rooted vines into potting soil or into your garden.

While this isn't an experiment, it is an exploration into how different plants grow differently. This exploration also invites you to think about the nutritional differences between root crops such as sweet potatoes, white potatoes and onions.

The golden color of sweet potatoes gives a hint: a single serving of sweet potato gives 438% of the recommended daily value of Vitamin A. In contrast, a single serving of white potato gives 0% of Vitamin A; so too for the onion.

Here's a comparison that comes with no hint: A single serving of sweet potato gives 37% of the daily value of Vitamin C; white potato, 35%; onion, 10%.

You don't have to grow the plants to research the differences in their nutrition facts: you can look'em up before you cook'em up. And notice that the results for potatoes are based on cooking with the skin on.

While you're doing your windowsill gardening this spring, it's worth noting that come June 1 UW-Madison will be celebrating the 100th anniversary of the discovery here of Vitamin A in 1913 by Elmer McCollum and Marguerite Davis. The Discovery of Vitamins is a centennial worth commemorating in our gardens, in our kitchens, on our tables and with our families.

Sweet Potato Facts

Russet Potato Facts

Yellow Onion Facts

by Thomas M. Zinnen, UW-Extension Bio-technology Specialist