There is still time left this spring to plant what are called “summer bulbs.” Planting bulbs is not a chore, it's an investment in color, in life, in joy. Unlike other kinds of investments, the cost is low, and you are pretty much guaranteed to get far more than you put into it. Even if you don't have a yard, all you need is a pot of soil and a bulb to enjoy the beauty of life right on your kitchen table.


But if the spirit of spring grabs you, and you know of a bit of earth that could benefit from a little beauty, here is a simple project that you can do with children, or on your own; You can create a "fairy ring," a mysterious circle of flowers, and give your child (and perhaps yourself) a chance to learn a little geometry at the same time.


A "fairy ring" is usually used to describe the natural circles of mushrooms that sometimes can be found both in the woods and in forests. One of the most famous rings of mushrooms is probably the one in Belfort, France and it is ridiculously large (it's about 2,000 feet across) and is nearly 700 years old.


Why do mushrooms sometimes grow in rings? People who saw these circles had no idea how they could come into being, so they invented stories. One story was that mushroom or floral rings sprang up in the places where elves or fairies had danced round and round in the moonlight. Scientists have other explanations for fairy rings of mushrooms, which you can read about at


To start making your ring, bang in a stake (or stout stick). That is your center point. How big of a circle do you want? That depends of course on how much money you have for flowers and how much earth you have to play with. Gladiolas (we call them "Daddy-olas" at my house) are relatively cheap and are planted about six inches apart.


Once you have decided how large of a circle you want to plant, divide that number in half. If you want a circle that is four feet across your string should only be 2 feet long. (The half of the width of the circle measured through the center is the “radius,” and the full distance — four feet in this example we call the “diameter”). Tie a loop onto one end of the string, and then cut it to the length you desire. Drop the loop over the top of the stake. Stretch the string tight. Right at the taut end of the string, put in another stake. Stand up, pull the line tight, and take a step or two, and again at the taut end of the rope, place another stake. Do this repeatedly until you have walked in a complete circle and left a lot of stakes in your circular path. You weren't dancing, and maybe you don’t feel like a magical creature, but you have just created the start of a fairy ring.


To determine how many flowers we can plant, we need to know the distance around our circle, which we call the “circumference.” Most children are taught that to find the circumference you multiply 2 times Pi (about 3.14) times the radius. When they see the equation in elementary or middle school and are asked to memorize it, looks like this; 2 π r.


We can move the two in the equation, so that it is next to the radius. Two times the radius, is the same as the diameter. Pi times the diameter, π d is another way of finding the circumference.


And why is this case? Because Pi is the number you get when you divide the circumference by the diameter, so if we multiply the diameter by Pi, we get back to our original value. Pi is always equal to a little more than 3. Frequently in math class, we use 3.14. With a diameter of about four feet, the circumference would be calculated as 3.14 x 4, and you get about 12 and a half feet.


If you are using gladiolas, you can plant them about six inches apart. With a circle of 12 feet, that means you can get two bulbs each foot, which would total 24 bulbs, plus another half foot, so we are going to be planting 25 bulbs.


Gladiolas sometimes get top heavy and tend to fall over, so after they have started to come up, use the joy that you get from seeing them arise as a motivator to put bamboo stakes next to each emerging plant. You can tie the heads to the bamboo poles for support. If you don't like the effort or cost of getting bamboo poles, you can either choose some other less top-heavy flowers or you can do what I have been experimenting with; I tie the gladiolas together with a ring of green jute that stretches all the way around them. If you want to try that, it is better to plant the bulbs a little deeper. With care and effort and judicious placement of string, you can get them to stand up pretty well.


You might start suspecting that I am getting paid by the gladiola growers’ association, but here is another reason to choose them; hummingbirds love gladiolas. Keep an eye out for these hungry birds in July.

There are many tales that suggest that stepping into the center of a fairy ring placed a person in danger of their magic. But other tales suggest that it was great good luck to do so. I think it's better to assume no harm will come of it, and my hope is that whatever flower you choose, and no matter how many you plant, that you get some joy out of this. Please send me photos if you do to,, and please put the word "Full Steam" in the subject line.


Rolf Parker tutors math and lives with his wife, the artist Cynthia Houghton, in Brattleboro and their 14-year-old boy. To see some of what they are up to, check out,