Have you ever seen the Chicago River on Saint Patrick's Day? As you probably already know, it is colored a brilliant shade of green for the occasion. This has been a Chicago tradition for decades now. It provides a bit of family-friendly fun for the kids, and a welcome midday distraction for the Loop's office workers. The green color achieved is shockingly bright -- I mean so bright you'll think your eyes are deceiving you.
So how do they dye the river green? I went looking and was delighted to find that it's no big secret. According to Green Chicago River, the event organizer's official site, it takes 40 pounds of vegetable dye to create a carpet of green that lasts four to five hours. Of course, they don't dye the entire river with that--just one section a couple of blocks long.
Interestingly, the vegetable-based dye replaced an oil-based dye that was initially used. Environmentalists lobbied for the change, arguing that oil-based dye was hardly an eco-friendly substance to be shoveling into a river.
Also of note: the earliest attempts to dye the river resulted in major overdoses. The first year, 1962, the organizers dumped 100 pounds of the stuff into the river, and the water stayed green for a week!
Want to replicate the Chicago River effect in your own yard? Try dyeing your pool green for a fun St. Patrick's Day celebration. Pool dyes manufactured by Party Pool come in red, blue and -- yes! -- emerald green, and can be purchased from pool supply stores like Pool Center.
Happy Saint Patrick's Day to you!