KILBOURN PARK — Renee Costanzo weaved through rows and rows of young plants at the Kilbourn Park Greenhouse, taking careful notes on a clipboard as she went.
Costanzo, program specialist for the greenhouse, was preparing for her busiest day of the year: the park’s annual plant sale.
Now in its 30th year, the plant sale will take place 9 a.m.-1 p.m. Saturday and Sunday at the Kilbourn Park Greenhouse, 3501 N. Kilbourn Ave. Neighbors line up at the Northwest Side park early to get their veggies, flowers, herbs and native plants, all priced at $4 each, Costanzo said.
This year Costanzo, Allison Webb, the park’s greenhouse program and event facilitator, and their trusty team of volunteers grew about 16,000 seedlings in preparation for the sale.
“One of our volunteers says it’s like a Black Friday for plants,” Costanzo said with a laugh.
For three decades the annual sale has helped sustain the Kilbourn Park Greenhouse, which is the Chicago Park District’s only teaching greenhouse.
The Kilbourn Park greenhouse as seen on May 6, 2026. Credit: Molly DeVore/ Block Club Chicago
Kate Hubbard, president of Friends of Kilbourn Park Greenhouse volunteer group, said the sale has been steadily growing in recent years. This weekend could be their biggest sale yet, she said.
During the sale, Friends of Kilbourn Park Greenhouse will launch a fundraising campaign for an outdoor classroom. The classroom, which will be used for the many classes and workshops held at the greenhouse, will feature a sort of pergola with tables and chairs.
Hubbard said the classroom is expected to cost about $65,000. Friends of Kilbourn Park Greenhouse aims to fundraise for at least half of the project this summer, matching whatever is left. Hubbard said the goal is to start construction this fall.
Donations to the classroom can be made here.
The classroom will help the garden’s mission of getting people out in nature and teaching them about growing food, Costanzo said. The greenhouse offers educational programs for people of all ages, including a Garden Buddies camp that introduces toddlers to the basics of growing.
“The hope is that you eventually don’t need the plant sale, that you start to feel comfortable planting and growing on your own,” Costanzo said.
A rendering of the planned Kilbourn Park outdoor classroom. Credit: Provided
Breathing New Life Into The Greenhouse
Tucked between tennis courts and Metra tracks, the Kilbourn Park Greenhouse is teeming with life.
The greenhouse’s two resident cats, Portia and Sylvester, gingerly stepped around trays of cucumber seedlings as the smell of basil wafted in from the nearby hoophouse on a recent May afternoon.
In addition to growing plants for the annual sale and hosting educational programs, the greenhouse is also used to grow plants that are displayed at parks across the North Side.
Built in the late 1920s as a small conservatory, the greenhouse was once the main producer of chrysanthemums for the city’s conservatories, Costanzo said. However, the structure gradually fell into disrepair and by the early 1990s, it was almost lost for good.
Catherine Dunlap, who served as the north region manager for the Chicago Park District at the time, was tasked with drawing up a plan to demolish the greenhouse, Costanzo said.
Instead, Dunlap, who had an interest in organic gardening herself, created a plan to bring the greenhouse back to life.
Dunlap and neighborhood volunteers worked to reopen the greenhouse and in 1996, they held the first plant sale.
Over the years, proceeds from the plant sale have gone toward making necessary repairs to the greenhouse. About 12 years ago, the aging roof was replaced using tax-increment financing money.
Portia, one of the Kilbourn Park greenhouse cat, as seen on May 6, 2026. Credit: Molly DeVore/ Block Club Chicago
Today, the greenhouse is surrounded by a 25-plot community garden, a native plant garden and a nature play space. It gets 30-60 volunteers every week and hosts a full schedule of gardening classes.
The Park District and Friends of Kilbourn Park Greenhouse also hold seed swaps, food preservation workshops and cooking classes at the park.
“It’s important to continue to teach these skills, because they have been lost over the last generation,” Hubbard said. “We have to keep that knowledge going.”
Learn more about upcoming events at the Kilbourn Park Greenhouse here.
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