All About Monarchs: How to Attract, Raise, & Release Monarch Butterflies

Are you ready to experience actual magic in your garden? Few things in nature are as awe-inspiring as the lifecycle of a monarch butterfly. And being able to participate in their journey makes it exponentially more special! Monarch butterflies, like most pollinators and wildlife, are under threat by humans ever-increasing domination and abuse of the natural world. Urban sprawl, monoculture, pesticide use, and habitat destruction are harming our friends. Additionally, monarchs have some natural predators to contend with!

The percentage of monarchs that survive from egg to adulthood is very low. Researchers agree that less than 10% of the eggs that are laid survive to become adult butterflies. Some feel that this number may be significantly under 10%. To account for low survival in the wild, female monarch butterflies can lay 300-500 eggs in their short lifetime.

Monarch Joint Venture

One huge way you can help boost monarch butterfly numbers is to create a butterfly and pollinator-friendly garden! Check out this post about the top 23 plants for pollinators! If you want to take it a step further, you can help protect monarchs by actively shepherding them safely through their journey of metamorphosis. That is what we’ll talk about today.

So you’re interested in raising Monarchs, huh? Excellent!

Read along to learn about attracting monarch butterflies to your garden, how to create a safe space to raise them during their transition from caterpillar to chrysalis to adult butterfly, and eventually – release them!

We’ll also go over the basic life cycle of a monarch, so you’ll know what to expect as you witness it! Potential threats and predators to monarch butterflies that may be present in your yard will be discussed, along with best practices to keep them healthy, fed, and hopefully disease-free in your enclosures. At the very end of the post, make sure to tune in to the video of a monarch emerging from its chrysalis!

I plan to write many more posts about monarch butterflies in the future too, including fun facts, FAQs, troubleshooting, migration patterns, and so on. This post is intended to be a crash-course on “Raising Monarchs 101” to get folks ready for the monarch season, since there has been a huge interest in helping to raise and release them as we do!

Please note…

…we are not claiming to be experts over here! Nor are we perfect in our techniques. But we do try our best. We have done a ton of research, experienced very few losses, and we successfully released over 160 healthy, beautiful butterflies last year! Our garden is also a Certified Monarch Waystation.

The Monarch Butterfly Life Cycle

Range & Populations

Monarch butterflies, or Danaus plexippus, are indigenous to North America. They are commonly found from southern Canada down to South America and the Caribbean. A small population also resides in Hawaii, New Zealand, Australia, Spain, and the Pacific Islands!

Within the United States, there are three distinct populations. South Florida has its own non-migratory population of monarch butterflies, while the rest of the U.S. is divided by the Rocky Mountains. West of the Rockies is the “western population” and east of the Rockies is… you guessed it: the “eastern population”. In the fall the eastern population migrates to the cool, high mountains of central Mexico and the western population migrates to coastal California, where they spend the entire winter. Here on the Central Coast, we happen to live just one mile inland from a monarch preserve, where thousands come to overwinter!

Monarch butterflies can be found and raised virtually anywhere in the United States, and the aforementioned locations! That is, anywhere there is milkweed.

Egg to Caterpillar

Adult monarch butterflies lay their eggs on milkweed, and milkweed alone. Only 3 to 5 days later, a teeny tiny monarch caterpillar emerges. It usually eats the now-empty egg casing as its first bit of nutrition!

Next, monarch caterpillars (or as I call them, “cats”) go through 5 distinct stages of growth. These are referred to as their “instar” stages. Between each stage, the caterpillar sheds its skin to jump up to the next size. They’ll usually eat the sloughed skin too! As they grow, the caterpillar spends approximately 1-3 days in each of the 1st instar through 4th instar stages, and a final 3-5 days as a 5th instar. The rate of development and time in each stage is temperature dependent. Warmer conditions speeds things up, and cold slows them down.

During their time as a “cat”, they rapidly eat milkweed. They have to eat nearly non-stop in order to keep up with their incredible growth rate. Monarch caterpillars increase their mass by 2,000 to 3,000 times their “birth weight” in just 9-14 days!

Caterpillar to Chrysalis

Once they’re fat, happy, and ready, the 5th instar cats will leave their host milkweed plant in search of a safe place to pupate. Monarch caterpillars can travel over 30 feet away from the milkweed to find the right spot! In a garden, they’ll often choose the underside of picnic tables, planter ledges, windowsills, along with the underside of leaves or in shrubs.  In an enclosure, they usually prefer the top of the container, or sometimes the side. They prefer to find a rough textured surface over a smoother one.

The monarch caterpillar creates a silk pad, spinning and depositing silk with its mouth. It then turns around and attaches its hind end to the silk button, and hangs upside. They curl up slightly, forming a J -shape. Thus, this stage is often referred to as “hanging in J” or simply “in J”.

Within a day or two of hanging in J, they go through one last molt. This can take longer in cold conditions. You’ll know they’re close to shedding and changing when they hang more straight rather than in J. The antennas will also go thin and limp immediately beforehand. Then their skin splits, starting at their head end.

Next, the caterpillar will give you the most trippy, fascinating show you have even seen! Check it out in time lapse below. The emerging pupae will wiggle and pulse and flail around, shrinking down from a lumpy caterpillar into a smooth green chrysalis in the matter of minutes. The skin usually falls away during this dance. It can take a full day or two for the chrysalis to completely harden, so avoid moving or disturbing it until then.

To learn more about moving and hanging a chrysalis when needed, see this post.

View this post on Instagram

🐛 June, in her transformation from caterpillar to chrysalis 🦋 What a crazy, magical dance! And no, I didn't speed up the video when she suddenly kicks it into high gear! That's their way of fully getting the caterpilllar skin bundled and off. The monarch caterpillar will usually hang "in J" for 12-18 hours before they shed their skin a final time and emerge as a chrysalis. You know they are close to changing when their J straightens a lot out more, and their antennas go shrivelled and limp. Now she'll bere in there for 10-14 days, on average. Or like Tilly, a month. Here we go again! 😄 I got to hang out with Miss Tilly this morning too, while she was laying eggs ALL over the milkweeds! 🌾 . #monarchcaterpillar #monarch #deannasbutterflies

A post shared by Deanna ~ Homestead and Chill © (@deannacat3) on Jun 10, 2018 at 10:46am PDT

Pretty trippy, huh?! If you’re interested in watching a normal, non-time lapse version of the process, check out our YouTube video of this dance up-close and personal!

Chrysalis to Butterfly

Once the chrysalis is formed, their insides turn to bright green goo as they rearrange their entire being and biology from caterpillar to butterfly. Metamorphosis. It’s bananas. Anywhere from 10-20 days later, they’ll emerge as a fresh adult butterfly! The average time a monarch spends in chrysalis is about 2 weeks.

You’ll know when a butterfly is close to emerging (also known as “eclose”) as the chrysalis changes colors. At first, it will be slightly darker green, but you’ll start to make out the wings through the casing. Then it becomes darker, as the monarchs black and orange colors show through even more. On the day they emerge, the chrysalis will be virtually transparent, becoming very thin. The final telltale sign that the butterfly will eclose at any moment is when the top striated portion of the chrysalis starts to expand like an accordion.

When a monarch butterfly emerges from its chrysalis, it hangs upside down from the empty casing, holding on by its feet. They may also climb onto another nearby surface. Its wings are folded up at first, and its body will be engorged with fluid. Don’t let the folded wings scare you! That doesn’t mean it has OE (discussed below). They should straighten out.

Hanging upside down immediately after emerging is absolutely essential for a monarch to live a normal life. If one of yours falls and you see it right away, hang it back up! As the new butterfly hangs, they pump fluid from their body into their wings, slowly filling and expanding them. It takes several hours for them to fully dry and be able to fly.

Life as a Monarch Butterfly

A monarch butterfly’s first day out of chrysalis will usually be spent hanging, and pumping their wings. They may not take their first flight until the following day. Freshly emerged butterflies don’t need nectar to drink for the first 24 hours. Once they’re fully dry, I place our monarchs out on a favorite nectar flower, like verbena or zinnia. And then, they’re off!

Did you know that the lifespan of an adult monarch butterfly is only 2 to 6 weeks? The females spend their short, beautiful little life laying as many eggs as possible. The males spend their time patrolling their “territory” for females, and will often chase off other male butterflies and even hummingbirds from their garden of choice – ours included!

One special type of monarch does live much longer however! The fourth generation of monarch butterflies that are “born” during the fall each year are called Super Monarchs. They’re the ones that are destined to migrate up to 3,000 miles in the winter, and can live up to 6 months! Super monarchs spend the winter in warmer southern regions, and return (at least part way) to northern climates in spring, in search of mates and milkweed to lay eggs on.

Then the cycle repeats itself. And oh, what a magical cycle it is!

How to Attract & Find Monarchs In Your Garden

Milkweed

The single best way is to attract monarch butterflies to your garden is to plant milkweed. Where there is milkweed, there will be monarchs! This is because milkweed is the one and only food source for monarch caterpillars. It is their “host plant”. Therefore, this is where the adult female monarch butterflies will lay their eggs – so their babies will have immediate access to food. Ensure the milkweed you buy has not been treated with pesticides. Ask the nursery and distributor.

Depending on where you live, monarchs may start to show up in your area in search of milkweed between March and July each year, as they return from their overwintering in Mexico or California. The Florida population does not migrate.

Once milkweed is planted in your yard, all you have to do is wait and watch. If you start to see monarch butterflies visit your yard, you should also notice the females laying eggs on it. They’ll tap their torso to the underside of the leaves, depositing eggs. You can collect leaves with eggs on them and start the rearing process very early. Alternately, you could wait until they have hatched and collect caterpillars – which is what we prefer to do. Remember, check the undersides of leaves for the little caterpillars!

No, we don’t buy our monarch eggs or cats online. However, I have heard of such a thing – for classroom lessons, for example! You could give it a go if you’d like to, but please ensure they’re normally present in your area, and that you are prepared with everything they need. Otherwise, see if you can entice them to come naturally!

Types of Milkweed

There are over 100 species of milkweed (Asclepias) with a huge diversity in foliage, flower color, size and appearance. Despite the wide variety, all types of milkweed are host plants for monarchs! It is best practice to grow milkweed that is native to your area, which will be most suited for your climate. Check out this article by Monarch Butterfly Garden to find which types of milkweed are native to your region. Also, check with your local nurseries!

When you buy started plants, be sure to ask the nursery or grower about their pesticide use. You do not want to bring home milkweed that has been sprayed!

Tropical milkweed is a popular option because the monarchs love it, and it is fast and easy to grow. However, tropical milkweed do not die back in winter as other native species do, which can lead to a disruption in the monarchs natural migration pattern. If you choose to grow tropical milkweed, ensure you cut it back for the winter to about 6” and remove foliage. Do this no later than Thanksgiving in California and southern states, and by late October in northern States. Cutting back milkweed also helps prevent the spread of OE, a parasite that inflicts monarchs. This practice doesn’t apply to southern Florida, where a non-migratory population of monarchs resides – though planting native milkweed is still encouraged!

Other Nectar Sources for Monarchs

Adult monarch butterflies will sip on nectar from milkweed plants too, but have much wider options for food than their larval form. Monarch butterflies enjoy the nectar from flowers like verbena, zinnias, coneflower, blazing meadow star, agastache, Mexican sunflower, butterfly bush, and more! Read more about the top 23 favorite pollinator plants here.

If you plant these types of flowers along with milkweed, and avoid the use of pesticide sprays in your yard, you’re giving monarchs a stellar helping hand! However, if you intend to take it a step further and bring in monarchs found in your yard to raise them, you need to plan in advance! This includes gathering some basic supplies, and a stockpile of milkweed

Everything You Need to Know About Raising Monarch Butterflies

As beautiful and fairly straightforward the process of taking monarchs into captivity may appear, it isn’t quite as simple as you may imagine. If we are essentially intervening in their natural process, we want to ensure more benefit is created than harm being caused! I know we all have good intentions, but there are definitely some best practices to be aware of, as well as some no-no’s to avoid.

Let’s get prepared.

Supplies You’ll Need to Raise Monarchs

Here is a brief list of all the supplies you’ll find useful to responsibly raise monarchs:

• A steady supply of milkweed. A lot of it!
• An enclosure. It is recommended to have a few different “housing” options for caterpillars and butterflies at different stages of life.
• Stem vases or floral tubes for milkweed cuttings.
• Diluted bleach spray for sanitizing.
• Hand vacuum for “frass” aka caterpillar poop (optional, but handy)
• A monarch journal, for keeping track of new butterflies as well as documenting issues

Now let’s talk about all of this in more detail.

Milkweed, Milkweed, Milkweed!

The first and most important step in your monarch-rearing journey is having a steady, ample supply of milkweed ready and waiting.

Plan to have several large established milkweed plants in your garden, or dozens of potted plants, ready and available well before you start considering taking in monarchs. You know the children’s book “The Hungry Hungry Caterpillar?” They didn’t get that idea from nowhere. Those monarch cats can EAT! A lot.

If you don’t have an ample supply ready, you’ll be faced with the awful situation of running out of food for your babies. Despite having dozens of milkweed plants in our garden, I can’t tell you how many special trips I made to our local nursery for more milkweed last summer. Fortunately, our local nursery always carries milkweed plants and is committed to sourcing them from growers who do not spray or otherwise treat with pesticides. Do not trust a label just because it says “pollinator friendly”. ASK! Contact the grower directly, not only the seller.

I hate to say it, but a couple small plants just won’t cut it. That is, unless you only plan to bring in and raise a few monarch cats. I urge you to only bring in an amount you can manage and responsibly raise. Don’t go collecting every baby caterpillar you can find! If you don’t have quick access to a local nursery and only have a couple small milkweed plants on hand, you may not be adequately prepared for this season.

Why bring monarch caterpillars into an enclosure?

Why don’t you just leave them out in the garden, you ask? Well, that is certainly what some folks opt to do, letting nature take its course. On the other hand, some gardeners see that the monarch caterpillar population in their yard is struggling and in need of help! That is the situation we were in. After seeing monarch cat after monarch cat succumb to a sad death, or mysteriously disappear, we knew we wanted to step in to protect them from predators. We’ll talk more about monarch predators in just a moment.

In addition to providing them a safe, predator-proof space to thrive, rearing monarchs is a very fun, fascinating, and rewarding experience! This is especially true for kiddos. It provides for an excellent, hands-on, up-close opportunity for them to learn about the life cycle of monarch butterflies.

However, keep in mind that death is also a part of any natural life cycle – including premature death. Things may not always be pretty and picture-perfect in your monarch rearing efforts, so do be prepared for a few sad moments. A “good” survival rate for caterpillars raised in captivity is about 80-90%. If you’re losing more than 10-20%, something may be wrong. Hopefully by the time you’ve finished reading this article, you’ll have a better idea of how to prevent such issues.

Monarch Predators

Fortunately, the list of predators to monarchs is fairly small. Milkweed is toxic and bitter to pretty much all other species, humans included. By consuming it, monarch caterpillars become very bitter and distasteful too. Thus, birds (who usually love all sorts of caterpillars and worms!) typically do not eat monarch caterpillars.

However, lizards, toads, ants, predatory stink bugs, and some spiders will eat them. Mice may eat chrysalids too. The two more prevalent predators we battle here are wasps and tachinid flies. They are what drove us to start raising monarchs. Another very common threat to monarchs is a parasite called OE, short for Ophryocystis elektroscirrha.

Wasp damage is fairly obvious and straightforward. You will either observe the wasp on the caterpillar, actively eating it, or see the remnants of a half-eaten, collapsed, gooey caterpillar. Other times, your cats may simply seem to vanish from the milkweed plant as if it was taken by a larger predator.

Tachinid Flies

The harm caused by tachinid flies is far less obvious, until it is too late. These small red-eyed flies lay their eggs on monarch caterpillars, and the tachinid larvae that emerge are parasites. Tachinid fly larvae burrow into the monarch caterpillar, and feed on it from the inside out. They’re known to eat non-essential tissues first, so the caterpillar will often live for quite a while despite its parasitic infection within. Tachinid flies generally go after larger caterpillars and the chrysalis itself.

Telltale signs of a tachinid fly larvae infection include:

• The monarch caterpillar gets skinnier with time.
• The caterpillar may attempt to pupate (hang upside in “J” and turn into a chrysalis) early, or when it appears too small to do so.
• Parasitized caterpillars will often die while attempting to form their chrysalis
• If they do make it into a chrysalis, it will become discolored, turning orange and then brown.
• Eventually, the tachinid fly larvae emerge from the infected caterpillar or chrysalis as little white maggots. When they do this, they leave behind white strands that will dangle from the caterpillar or chrysalis from which they emerged.
• Fallen from the caterpillar, you may be able to either find the tachinid maggots themselves, or their freshly-formed pupae – a reddish brown nugget that is about the size of a small mouse poop – which is what they change into before emerging as a new fly.

If it becomes obvious that tachinid flies are an issue in your area, experts say you can help by taking in monarch caterpillars as eggs or very small caterpillars (1st, 2nd, and 3rd instar). If you wait and take in only the largest caterpillars (4th and 5th instar), there is chance they may already be parasitized.

What is OE?

“Ophryocystis elektroscirrha (OE) is a debilitating protozoan parasite that infects monarchs. Infected adult monarchs harbor thousands or millions of microscopic OE spores on the outside of their bodies. When dormant spores are scattered onto eggs or milkweed leaves by infected adults, monarch larvae consume the spores, and these parasites then replicate inside the larvae and pupae. Monarchs with severe OE infections can fail to emerge successfully from their pupal stage, either because they become stuck or they are too weak to fully expand their wings. Monarchs with mild OE infections can appear normal but live shorter lives and cannot fly as well as healthy monarchs.”

Monarch Joint Venture

OE is very common among the Florida population of monarchs, moderately common in the Western United States, and less common in the Midwest. We have been very lucky and haven’t struggled with obvious signs of OE here on our homestead.

If a monarch butterfly emerges from its chrysalis with severely deformed, crumpled wings, the cause is most likely OE. They may be weak and fall from the chrysalis casing, unable to hang to dry as needed. When this happens, or when you have any other obvious sign of disease in a butterfly or caterpillar it is important that they’re removed from the enclosure, and everything is thoroughly sanitized as quickly as possible. We’ll talk more about sanitizing methods below.

The most humane way to euthanize a sick or suffering butterfly or caterpillar is by freezing it. They will go dormant, and then freeze. Some folks prefer a more quick death, squeezing the inflicted insect in a paper towel. I can’t bring myself to do this.

However, not all monarch butterflies that carry OE will show obvious signs. When they emerge, they may appear fairly normal. Carrier butterflies will still slough off OE spores from their wings. Because of this, experts suggest that chrysalids should be kept in a different enclosure from the rest of the caterpillar population. That way, if the freshly emerged butterflies are shedding OE spores, the entire colony is not infected. We do our best to keep the majority of our caterpillars separate from our chrysalids, though I’ll admit a tiny bit of mixing does go on, as we’ll discuss next.

Monarch Enclosures: Options, Upkeep, & Best Practices

Different Cages for Different Ages

Did you know that larger monarch caterpillars can (and do) eat smaller monarch caterpillars and eggs? Yep. I don’t think it’s intentional though. The issue is, the big cats have a big appetite! As they gobble up their milkweed, they’ll also gobble up anything that is on the leaf – including other little monarch cats or eggs. Therefore, it is best practice to keep the smallest caterpillars in a separate enclosure than the larger ones.

Keeping them separated by their stage in development helps prevent anyone from accidentally eating one another. Additionally, this helps prevent the spread of disease, as we discussed previously in the OE section above. We have three different enclosures for various stages; two for separating caterpillars by size, and one for chrysalis and emerging butterflies.

One way to accomplish this is to carefully, physically relocate the chrysalis that have formed in one enclosure into another enclosure where they’ll emerge into butterflies. We do this quite often. Check out this article to see how! To reduce the number that we have to relocate, we also move some of the biggest cats into the chrysalis enclosure right before they actually transform. We’ll discuss this momentarily.

There are many options for monarch rearing enclosures, including mesh tents, aquariums, DIY cages, converted screen reptile cages, or even food storage containers!

Using plastic containers or jars

Because they’re so tiny at first, many people keep their smallest caterpillars and eggs in containers like glass jars, plastic food storage containers, or similar. The container must be breathable, so use mesh/screen lids or add air holes – but not so large they’ll escape!

Milkweed cuttings are placed inside, often times in floral tubes to maintain freshness. We’ll talk more about milkweed cuttings later! On the other hand, some folks simply lay milkweed leaves and stems in the container on top of a lightly damp paper towel. New leaves are added as frequently as needed to keep them fresh – once per day or even more often.

The humidity inside smaller enclosed containers must be carefully monitored. The goal is to have just enough humidity to keep the milkweed fresh, but not so much that their poop (called “frass”) develops mold. To maintain sanitary living conditions, clean out their container to remove the frass often.

Mesh butterfly tents

You could also use mesh tents as an enclosure to raise monarch caterpillars. This is what we use, in addition to our larger homemade wood-framed screen cage. We have two of these mesh tents! They come in small, medium, and large sizes, each rated for a certain caterpillar population capacity and size of plants.

One of our tents is the designated “baby tent” where the smallest monarch caterpillars are housed – 1st through 2nd or 3rd instar.  Another tent is designated for “teenagers” – 4th and 5th instar. Inside, we keep potted milkweed plants. They are rotated out periodically to maintain freshness and prevent the spread of disease. When needed, we also use cuttings.

Important safety note about using butterfly tents: The caterpillars seem very drawn to hanging out on the zipper portion, or even hanging “in J” and forming their chrysalis there. Therefore, it is important that you check the zipper area very carefully (by looking through from the other side) and unzip your tents slowly! I will admit, I caught a cat in the zipper once. It was so traumatic that I will never, ever do that again.

Our Big Butterfly Enclosure

Our DIY wood-framed enclosure is used primarily for chrysalides and emerging butterflies. Once the largest 5th instar cats in the “teenager tent” start to wander away from their milkweed and explore the top of the cage – a sign they’re looking for a spot to hang and pupate soon – we relocate them into the wood “adult” enclosure. Sometimes, they trick us and aren’t quite ready to change yet! So we do leave a potted milkweed plant (or cuttings) in this enclosure for them to grab their last meal from as needed, and rotate it out frequently.

The cats that we move into this cage usually choose to form their chrysalis on the top ceiling of the enclosure. For the chrysalides we physically relocate from the teenager tent, we included a couple of secure, rough-textured branches that we can easily tie the chrysalis to with waxed floss.

Specs

Unfortunately, I don’t have “plans” of the enclosure we built, but I can try my best to describe its stats for you! The cage portion is 15 inches deep, 36 inches tall, and 27 inches wide. It has a separate base/stand that it sits on, that we also built to the same depth and width, but is about a foot shorter. This makes it easy to move about or store away in the off season if needed.

We choose these dimensions to suit the space we knew we wanted to keep the enclosure. It is wide and deep enough to fit a couple potted plants in. It is definitely taller than necessary. Monarch butterflies only need about 4 to 6 inches of space below their chrysalis to safely emerge, hang, and dry. I simply wanted it nice and tall so it would be at a comfortable level for working in, and observing them.

Take a look at the photos to get a better idea of how we constructed it. The simple wood frame was made with redwood 2x2s. A fine mesh insect screen was added to line the inside of the cage frame, creating one smooth continuous screen all the way around. This helped to eliminate extra nooks and crannies they could try to squeeze into, or hang from. The bottom is plywood, covered with inexpensive sheet vinyl for easy cleaning. The hinged door shuts tightly with an eye and hook latch. Also, it has a lining of thick weather stripping between the door and frame to prevent any gaps.

Transferring caterpillars between cages

It is best practice to avoid moving caterpillars into various cages continuously, to avoid the spread of potential disease. To be honest, we aren’t 100% perfect here, but we do try our best!

Here are a few example scenarios of what we may do. I may collect a bunch of tiny 1st and 2nd instars all at once, and put them in a tent or smaller container. I also may find a bunch of 3rd, 4th and 5th instars during that hunt, and put them together in another tent. Being that each group was around the same stage in development when collected, they can all theoretically live together in their respective tents up until they get moved to the wood enclosure.

As much as possible, I try to move them through the cages in groups, and do a deep cleaning and sanitizing between groups – discussed more at the end of this post. And of course, changing out the milkweed. Though, the timing isn’t always perfect.  They don’t always mature at exactly the same rate. And I am always tempted to take in more…. So sometimes, I do move individuals between cages as needed.

The good news is, we have experienced very little signs of monarch disease in our garden, with the exception of tachinid flies – which isn’t contagious among members in an enclosure.

Temperature & Climate

Keep your outdoor enclosure somewhere that is protected from strong wind or rain. It is best if it receives nice bright ambient light for potted plants, but is protected from the hottest afternoon sun for the cats. In very hot summer climates, it may be best to locate your enclosures in full shade. Ours receive morning to midday sun. We have a piece of shade cloth readily available to drape over the cage for hotter-than-average mornings.

Monarchs of all stages may die if exposed to temperatures over 95°F. Temperatures rarely get that hot here, but during a freak heat wave last summer we did bring our cat enclosures inside for a couple days. I was likely being a bit overprotective, since they survive Florida and Texas summers, but that temperature threshold is still worth noting!

A lot of people who raise monarch butterflies do so in enclosures indoors. However, recent studies are showing that indoor-reared monarchs may not be able to properly navigate and migrate. Therefore, it is best practice to keep them outdoors as much as possible.

Cool temperatures also affect monarchs. They will die if they’re exposed to freezing conditions, but most of them have migrated on to warmer places during the time of year this would be a concern. Monarchs go virtually dormant in temperatures less than 55°F. They are less active in cooler conditions, meaning they’ll eat less, grow slower, and take longer to transform between stages.

For example, we have had a monarch caterpillar hang “in J” (waiting to transform into a chrysalis) for nearly two weeks during cool spring weather. On the other hand, it can take as little as two days to hang and pupate into a chrysalis in the late summer! Similarly, our very first monarch “Tilly” spent a full month in chrysalis before emerging as a butterfly, while the average summer monarch will emerge from its chrysalis in only 10-14 days.

Ways to provide milkweed for monarch caterpillars: potted plants or cuttings

Inside each enclosure, a supply of fresh milkweed must always be provided for the hungry, growing monarch cats. For baby containers with little caterpillars, many people simply pluck off fresh leaves from an available milkweed plant, adding them to the container once or twice per day. For larger enclosures, it may be possible to place potted milkweed plants inside.

The milkweed plants in our yard are still fairly young. Meaning, we can’t afford to take clippings from on a regular basis without decimating them. Therefore, we primarily use potted milkweed plants in our monarch enclosures. Yes, we have dozens! However, if you are fortunate to live somewhere with access to large, wild, abundant milkweed plants, taking cuttings may be the way to go! We are slowly transitioning to using more and more cuttings, as it is the suggested best practice for sanitation.

How to take milkweed cuttings

I recently learned a great tip for keeping milkweed cutting fresh and spry! In the past, the cuttings we did take went limp very fast, even when stored in water. The cats were not happy with this sub-par food. It turns out that when a milkweed stem is first cut, the latex substance that it oozes clogs up the wound –  and doesn’t allow water to be taken up! So the trick to keep milkweed cuttings fresh is this: cut the stem twice, and run it under warm water, then put it in water.

Place milkweed cuttings in water, in a container with a narrow opening. For example, a glass jar is not ideal, unless it has a lid and you insert it through a straw hole or something. We don’t want the caterpillars to accidentally get into the container and drown! This is where floral tubes come in handy! Most serious monarch enthusiasts use floral tubes like these to keep milkweed cuttings fresh, and caterpillars safe. Easy-to-clean racks can hold the tubes upright. Apparently this is so common, that when I was searching for floral tubes to buy recently, they are listed on Amazon as “floral tubes and racks for milkweed cuttings”. Ha! We got this rack with extra-large 60 ml tubes to try out this season.

Another option is to place cuttings in a narrow-neck bottle and tightly wrap the opening with a cloth or paper towel, preventing caterpillar access.

Monarch Enclosure Maintenance & Sanitation

Frass Removal

What goes in, must come out…. You know how I said monarch caterpillars eat a lot? Well, that means they also poop a lot. They’re pretty much like chickens! Caterpillar poop is called frass. The good news is, frass isn’t nearly as nasty as chicken poop. It doesn’t smell at all! However, it can get moldy and start to harbor bacteria with time. The goal is to keep the caterpillar enclosures as sanitary as possible, meaning routine cleaning is needed. We try to remove built up frass every couple of days in our baby tent (they poop less) and nearly every day in the teenager or adult enclosure.

One potentially easy way to remove frass from their cage is to pull out the contents (potted plants, cuttings, caterpillars, paper towels, etc) and gently shake the frass out of the now-empty container. This is easy for tiny containers like those used for smaller cats. This is also a feasible option for mesh tents, if all the cats are hanging out on the milkweed. However, if they’re crawling all of the enclosure, that method could get a bit tricky.  

A method I read about on a monarch caterpillar forum that we have adopted is using a small hand vacuum! It makes daily cleaning of cat poop very quick and easy! You know I mean caterpillar poop by now, right? Ok good. Obviously, care still needs to be taken to avoid sucking up any babies, and the vacuum also needs to be sanitized routinely.

One last solution I just stumbled upon is using an inexpensive plastic pot saucer tray under the milkweed pot or cuttings. See the image below. This would still need to be removed and sanitized periodically, but would help keep the bottom of your enclosure much more clean!

Sanitizing monarch enclosures

In addition to frequent routine clean-ups, you’ll also need to perform a deeper sanitizing of their enclosures and supplies (e.g. floral tubes) on occasion. I haven’t read any hard fast rules about sanitizing frequencies, but here is how we approach it: I try to do a deeper sanitizing every weekend, or more often if needed. The “if needed” would be if I saw any sign of disease from a caterpillar or emerged butterfly. In that instance, I remove the milkweed plant to be kept in quarantine until next season, and replace it with a fresh one after the entire enclosure has been sanitized.

How to sanitize

Warning all hippies, cover your ears! I am about to use the “B” word. To sanitize monarch enclosures, every expert resource suggests to use bleach. So that is what we use. While we try to avoid chlorine bleach as much as possible, we don’t want to mess around when it comes to our monarch’s health!

It is my understanding that bleach is the best solution for killing things like OE spores or other harmful bacteria. Some serious monarch enthusiasts even soak their milkweed cuttings in a dilute bleach solution and then rinse it off with tap water before feeding it to their cats! Sure, sometimes straight undiluted vinegar can be quite effective at disinfecting things, but the issue is also contact time. Vinegar required nearly 20 minutes of contact time to work. Bleach works in 30 seconds. When we are literally juggling dozens of wriggling wild cats, time is of the essence.

To sanitize our monarch mesh tents, we pull everything out and spray it down thoroughly using a spray bottle with about 5% diluted bleach solution – or one part bleach to 19 parts water. Let it sit for for at least 30 seconds, up to a couple minutes, and then rinse with fresh water. For the chrysalis enclosure, I obviously don’t take them all out. I do my best to carefully spray the floor area and screen side walls below them, avoiding misting them.

Releasing Monarchs – Eclose Day

So, we’ve made it this far! You’ve gathered your milkweed, created a clean and safe haven to raise monarch caterpillars, and have seen them through their transformation from caterpillar to chrysalis.

And now, for the moment we’ve all been waiting for – they’re about to emerge as butterflies! Congratulations!

Supposedly, it is most common for monarch butterflies to eclose from their chrysalis in the morning. However, we have experienced them emerge during all hours of the day! But never overnight. Remember, once they emerge, it is essential for them to have space to hang upside down. It will take several hours for them to dry and be ready to fly.

If the weather is not ideal on release day (for example, it’s pouring rain, extremely windy or hot, and so on), it is okay to keep them in the enclosure for a bit longer as needed. Freshly emerged adult monarch butterflies do not need to drink nectar for the first 24 hours. If it is going to be longer than that, you have a few options aside from flowers! Supplemental treats that can provide monarch butterflies essential sugar include orange slices, watermelon, or ripe, wet, smushed banana pieces.

Fun fact: Monarch butterflies taste with their feet!

When the time is right, bring your precious baby butterflies out onto a nectar flower of choice. If they’re really dry and ready to go, they might just fly off! So take care in gently cupping your hands around them if you are transferring from indoors to outdoors. When you set them out, they may still want to hang upside down, so I always place them in that position.

And now, they are free! It is so bittersweet…

What do you think? Are you ready to help raise and release monarch butterflies this season? Or, maybe you need another year to prepare? Either way, I hope you have found this article informative, helpful, and exciting. Raising monarch butterflies is seriously one of my favorite things to experience in the garden! I love them SO much! Hopefully, you will get to experience it too.

If you liked this article, I bet you’d also be interested in supporting all types of wildlife in your garden! Our property is a Certified Wildlife Habitat, and gardens of all shapes and sizes can do the same. Check out this article to learn how to transform your yard into a more sustainable, equitable, wildlife-friendly place.

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