Phew. This was my first question. 

"(Old bowling greens are often doused with a range of toxic chemicals, but soil tests were run before anything was planted and came back completely clear, Barnes says)."

Out of old bowling green, hundreds of kilos of fresh food, thanks to volunteers | Stuff.co.nz
https://www.stuff.co.nz/life-style/homed/garden/133015868/out-of-old-bowling-green-hundreds-of-kilos-of-fresh-food-thanks-to-volunteers