Back to Journey North for Kids   Can Milkweed Grow Fast Enough? There are two monarch caterpillars in the picture below. Can you see them both? It only takes two weeks for monarch caterpillars to grow this much! Do you think a milkweed plant could grow fast enough to feed more than one caterpillar? Think about an experiment you could do to find out. What would you need to know? Photo: J. Gallion Copyright 2006 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form.