How to Care for a Caterpillar in a Jar Until It Becomes a Butterfly

A fun early spring and summer activity for kids is collecting caterpillars in jars and keeping them as pets until they turn into butterflies. You can also purchase butterfly kits online and order caterpillars, cocoons and larvae. The kits come with easy-to-follow instructions for keeping your caterpillar safe, protected and nourished until it pupates into a butterfly. But if you have found caterpillars outdoors and are looking for instruction in their care, there are some easy steps to follow. Collecting caterpillars to watch them turn into butterflies is easy, fun and educational.

Things You'll Need

  • Jar or tank with a netting for lid
  • Spray mister
  • Florist tube
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Instructions

    • 1
      A large jar with a net on the top is the best place to keep your caterpillar.

      Clean a small fish tank or one-gallon jar and allow it to air dry. Place some netting or screening over the top of the tank or jar and hold it fast with a rubber band or tape. Do not use a jar with a top with holes punched in it as the sharp metal could slice the caterpillar.

    • 2

      Place the branch with the caterpillar into the jar. Add several other sticks to the jar as well, so that your caterpillar has places to explore and can find a suitable stick on which to pupate. Take special note of the plant on which the caterpillar is living and feeding.

    • 3

      Remember the plant you got the caterpillar from so you can come back for fresh leaves to feed the caterpillar, this will be the only plant it will eat. It is important to place fresh cuttings in the jar every day. Remove any old or uneaten leaves. Keep the leaves fresh by placing them in a florist tube.

    • 4
      Caterpillars will only eat the leaves from the host plant it has been living on.

      Mist the jar or aquarium with water from a spray bottle every few days so it can drink the water droplets. Do not place a saucer of water in the jar or your caterpillar could fall in and drown.

    • 5
      Watching a butterfly hatch from a pupa of a caterpillar enables you to see nature's wonders up close.

      Monitor your pet daily making sure that all the eaten leaves are replaced with fresh new ones and there is enough water. Also check to make sure other bugs have not gotten into the jar, spiders can eat caterpillars. Make sure the jar does not become moldy from the humid environment.

    • 6

      Discontinue providing food and water once your caterpillar forms its cocoon. Just watch for a butterfly to emerge. Usually this takes two to three weeks. Then set it free. Butterflies usually can't live very long in captivity.