This story was originally published by Grist in partnership with Chicago Public Media, and is reproduced here as part of the Climate Desk collaboration.

Renee Costanzo cranked on the rusty pulley with both hands, watching the greenhouse roof creak open in sections. A breeze of spring air swept over 12,000 seedlings lined up in plastic trays in the Kilbourn Park greenhouse.

Costanzo, the Chicago Park District’s only full-time employee at the north-side greenhouse, spearheads a months-long effort to grow more than 15,000 plants, including vegetables, greens, and flowers, to get them ready in time for the Kilbourn Park’s annual plant sale.

The massively popular sale, which took place earlier this month, typically draws upwards of 1,100 people every year, with local gardeners lining up around the park waiting to snatch up plants at $4 a piece. But this year, attendance broke records — more than 2,300 shoppers turned out.

“We generally start these annuals at the end of February,” said Costanzo, pointing to rows of popular annual flowers like zinnias, marigolds, and geraniums, which provide bright blooms all summer long before dying at the end of the season. “So we’ve been coddling and loving these babies for months now, and we just want to get them into happy homes.”

For decades, Chicago gardeners flocked to the Kilbourn Park sale to pick up tomatoes, cucumbers, and some annuals — the standard starter kit for backyard gardeners. But this year, the park responded to a relatively new demand:........

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