Raising Monarch Butterflies

Watch the metamorphosis from egg to open wings!

Why we raise butterflies~

We were inspired by a customer who was buying up as many milkweed plants as she could — tropical and otherwise — to raise monarchs at her home.  She taught staff members here her method to successfully raise monarchs from the egg stage to a fully winged adult.

Monarchs are endangered, so by safely raising some from egg to adult we are helping to preserve these amazing creatures.  We have been raising Monarch caterpillars since 2014 and we have since released hundreds of monarch butterflies each year!

Tropical Milkweed: The debate is ongoing, but some experts still recommend cutting back tropical milkweed in November.

Caterpillar housing

We use clear plastic shoe boxes which have lids that close — be aware that some boxes have an air gap between the lid and the box through which smaller caterpillars can escape!

Provide fresh air by either poking air holes in the lid or by opening the container twice a day for a few minutes.  When poking holes, be sure to poke the hole from the inside to the outside so that any sharp edges are on the exterior surface of the lid and will not scratch the soft tissue of the caterpillars.

Line the bottoms of the boxes with paper towels.  Caterpillars LOVE to eat, which means poop, or frass, will follow!  Change the paper towels daily to keep the boxes clean of frass.

After daily caterpillar maintenance we search for new eggs in our Butterfly Garden.

Monarch eggs

Monarchs lay their eggs almost always as a single egg on the underside of a milkweed leaf.  The adults do this intentionally to try to ensure ample supply of milkweed leaves for their offspring.

The eggs are an ivory color, and while they can be found on a variety of milkweed, we have found adults prefer to lay on our tropical milkweed (Asclepias curassavica) over all others in our nursery and grounds.  They also like antelope-horns milkweed (A. asperula).  Though antelope-horns milkweed is much harder to propagate for the nursery trade and not commonly seen for sale, it grows widely in the Austin and Hill Country area, and easily grows from seed in the landscape.  We have found from our observations of their behavior in the nursery and butterfly garden that monarchs are less eager to lay eggs on butterfly weed (A. tuberosa), pineleaf milkweed, and zizotes (A. oenotheroides).

Once an egg is located, we carefully pick the leaf on which it has been laid and bring it back inside to place in the box.  We do not bring in already hatched caterpillars as we have found that they have often been attacked by parasitic wasps and will die before they can become butterflies.

Larval stage

The eggs will change from an ivory color to a darker cream/brown when they are about to hatch, and are usually ready between 3-5 days.  Freshly hatched caterpillars are tiny, and don’t require much food for the first few days — in fact, their first meal is their egg case.  Don’t pick too much for them at the beginning as this could waste good leaves.  About three hatchling caterpillars can share a single leaf.

It is also important to ensure that their supply of milkweed has not been treated with any insecticides or other chemicals which could adversely affect the caterpillars.  We have been working for years with two trusted suppliers that ensure the milkweed sold in our nursery is safe for the monarchs.

Keep them clean!

Whilst the caterpillars are growing and eating in the boxes, hygiene is important.  We change the paper towels every day and keep the humidity level in the boxes at a comfortable level for the caterpillars by keeping the leaves moist and dampening the paper towels.  Take care not to allow mildew to grow and remove any leaves that show signs of it immediately.

It takes approximately four weeks for a monarch to grow from egg to butterfly.  During the caterpillar stage they will molt 4 or 5 times as they grow.  Picking up the caterpillar while they are in the molting phase can harm them!  Each time they molt they will crawl away from the milkweed and climb up the box wall to go through the process.  It takes a day for the caterpillar to molt into its next stage.

Pupa or chrysalis

When they are ready to pupate, the caterpillars climb up the wall of the box and crawl on to the underside of the lid where they spin a web from which they hang.  They hang upside down in a j-shape for a day, then go through a process where they slough their skin and a pupa emerges.  This transformation from striped caterpillar to a pale, light green pupa with gold spots happens within 10 minutes.

The chrysalis will hang from the lid for approximately 10 days.  Over time, the wings will start to become more pronounced within it; during the final days, the pupa changes color from bright pale green to a red/maroon color.  Air pockets begin to develop within the pupa and they usually hatch within an hour of dawn.  It only takes seconds for the pupa to open and the butterfly to emerge.

The Butterfly

Once the new butterfly emerges, it needs time for its wings to unfurl and dry before it can fly.  It usually takes about four hours before the butterfly is ready to be released.  During that time they are quite docile and can be handled, but only with great care.  Around noon, we release them into our Butterfly Garden, where they will find a plentiful supply of nectar plants!