When do you know if the rhubarb is ready to pick?
Rhubarb is ripe when the stalk is a dark red. If its still
mostly green, it's not ready to be picked yet, unless you want it
really sour!
Actually, there are two types of rhubarb and several varieties
of each type. Red rhubarb emerges with a red stalk that is
completely red. It's ready to pick whenever you're ready to pick
it, and a rhubarb that is constantly harvested will continue to
send out new stalks until it gets too cool at night.
Green rhubarb emerges green and will never turn completely red,
no matter how long you wait. Some varieties will have a reddish
base when the stalks get very thick.
Both varieties do not get 'sweeter' as the stalks get
bigger.