What does "average water" mean in regards to a plant?

My son brought home the lima bean plant that he grew into a sprout at pre-school. I have the worst luck with plants, and because it's my son's I don't want the little thing to die. I've put it where I *think* we get full sun every day (per the internet, they need "full sun") in the porch window. But it said they need "average" water. Could someone give me a more exact measuremant for "average" water? The plant is about three inches tall right now with a bean and it looks like a flower on it. Thanks!

What does "average water" mean in regards to a plant?
Donna has told you how to water but I just have to add to take it out of the window in full sun!!

Sunlight gets magnified through glass and it will be too strong for your little lima bean, scorching the foliage.

Place it on a windowsill where it gets morning sun only or move it further away from the window it is on at present so that it still gets light but is not in direct sunlight.
Reply:Average generally means giving the plant a good soak when the soil is mostly dry. When checking the moisture dig your finger down into the soil a little ways. If its wet don't water it, but if it's only damp or dry then it needs water. What is best is a large container w/ a trellis for climbing.
Reply:stick your finger in the soil about 1/2 inch if the soil is moist don't water it if the soil is dry water it.it means you have to keep the soil moist when it needs it.average is water it about once a week that is average.