Lots, surprisingly!
Just think of this: If you bite into a juicy strawberry this summer, chances are you're eating something that's actually been grown in a petri dish.
NPR's Dan Charles of All Things Considered tells us the secret life of strawberries:
That strawberry you just bought at the supermarket traces its ancestry to a microscopic particle of plant tissue that somebody cut from the tip of a growing strawberry stem five years ago.
That tiny bit of strawberry stem went into a little glass petri dish and grew into a new plant. Then it sent out dozens of little daughter plants called "runners."
"Those runners are basically clones of the mother," explains Daren Gee, owner of Daren's Berries in Santa Maria, California, whom I caught in the middle of his peak harvest time. "And then they plant those, and take the daughters off of that one, and do it again and again and again."
The whole process takes years. The plants are multiplied first in carefully controlled greenhouses; then in fields in the heat of California's Central Valley. Finally, the plants are trucked up into the mountains along the California-Oregon border. It's cold up there, which is crucial. Somehow the cold gets these plants primed for maximum production.
"And then they'll dig up these mother plants, and all the daughters, and they'll throw the mothers away and they'll send me the daughters," says Gee. It's those daughters that produce California's monster strawberry crop.