it can keep in the fridge (make sure it's unwashed and in a plastic bag) for 2-3 weeks. When you do use it, make sure the rhubarb isn't wilted, if it is then it isn't fresh and it will taste woody and bitter.
What nutrients are in Rhubarb? Even though rhubarb is
considered a vegetable, it is
most often treated as a fruit.
Rhubarb provides a good source
of vitamin C, fiber, and calcium.
It is usually eaten cooked, and
just like fresh cranberries,
rhubarb is almost unbearably tart
on its own. It needs the added
sweetness of sugar, honey, or
fruit juice to balance out the
acidity. Since rhubarb is primarily
used for pie, it is also referred to
by it's nickname the "pie plant".
WARNING! Never eat the leaves, neither raw or cooked. Rhubarb leves are toxic!
A cup is a measure of volume while pounds is a measure of weight so a direct calculation is difficult. If we only take liquid weight into account, one cup is eight ounces and two pounds would be 32 ounces so two pounds of rhubarb would equate to 4 cups.
Rhubarb is in fact a vegetable, one of the most unusual because it is eaten with sugar. The identity of rhubarb has vexed gardeners and chefs for years, so much so in fact, that a in 1947 a US court ruled it was a fruit.
It's considered a vegetable here in UK as the edible stalks of the rhubarb plant grow from a sturdy rhizone (underground stem), and the best stalks are long, thin, vibrant pink and tender, and are the result of being force-grown in artificial darkness.
Rhubarb leaves contains oxalate, which have been reported to cause poisoning when large quantities of raw or cooked leaves are ingested.
There is nothing dangerous about it. Rhubarb pie is wonderful!
Be sure to completely remove the leaves (they are toxic) then chop the stalks in medium sized pieces. You can eat these directly (they are very tart), cook them in a pan on the stove with sugar until they are soft, put them inside a pie crust with sugar and bake the pie, etc. They can be mixed with various fruits during cooking/baking (strawberries are common).
I've even been experimenting with using rhubarb in making ice cream. For this purpose after cooking, the rhubarb must be cooled and then passed through a food mill to remove all the fibers (their texture in unpleasant in ice cream).
The leaves should not be eaten but the stalks are edible, if you eat too much raw rhubarb stalk you will get a stomach ache. Best to cook it first, tastes much better cooked too.
Wait for the leaves to be fully opened and you can pull from May to August. This information applies to the UK, other area may have different harvest times