Winter Sowing Milkweed Seeds Part 3: Spring Your Seedlings

Spring is finally here, and the end of your winter sowing adventure is drawing near. Your first seeds are breaking through the soil and you can see them slowly rising inside your containers. Are you ready to spring your plants?

If you haven’t put together winter sowing containers, you’ll need to go back to the beginning take to gather your winter sowing supplies before following the 11 step process to winter sow your milkweed seeds.
Winter Sowing Results for Native Milkweed Seeds
Swamp Success!


STEP 1: Dig Containers into Soil

Once the soil softens enough for digging, secure the containers a bit more by digging them slightly into the soil. I surrounded the containers with rocks to insure they stay upright. Little did I realize, this would have another important benefit…

Winter Sowing Milkeed Part 3- Common Milkweed and Swamp Milkweed Winter Sowing Containers are dug into soil for both security and water retention

STEP 2: Water Your Containers

Your emerging seedlings need water when there is no visible condensation on the clear parts of the containers. When you water, water into the hole you just dug the container into, and not the top opening of your containers because that will disturb the soil.

The unexpected benefit is that the container will absorb more water through the bottom holes, because the dug out region will retain more moisture than the other surrounding soil, acting as a reservoir.

STEP 3: Cut off Duct Tape and Remove Container Top

Winter Sowing Milkweed Results for 2016?

Do this after your average final frost date. If you do uncover earlier, make sure to recover your seedlings on freezing nights, or bring them inside the garage.

STEP 4: Pinch off Weak Seedlings

If you pinch off the weakest seedlings, you’ll prevent overcrowding without disturbing the roots of your remaining plants. Since the seedlings are small, it’s also possible to remove some and replant elsewhere, if your green thumbs possess surgeon-like precision.

STEP 5: Continue Care

Making sure the containers don’t dry out is your number one priority. That being said  over-saturation  can also kill seedlings…especially if you have a torrential rainstorm and the container floods.

STEP 6: Spring Your Seedlings

When removing seedlings, make sure to dig deep enough to salvage the entire root. It shouldn’t be too hard to achieve this with young seedlings. So, how long should you wait before you remove them?…

I am not sure there is a correct answer to this question. You can transplant them as small seedlings or you can wait until the seedlings’ roots intertwine to create a fibrous mass throughout the container.

I found it quite easy to pull the seedlings apart (without harming them) after the fibrous mass had formed.

If pesky critters are the bane of your butterfly garden, perhaps potting a few plants to direct plant in fall would be good insurance.

Unbeknownst to many, rabbits and deer will quite happily munch on milkweed…especially young seedlings!

Winter Sowing Lessons Learned?

  • The soil in the two-liter pop bottles seems to maintain a healthier moisture level  than the over-saturated opaque milk containers. Perhaps because the two liter bottles absorb more light and heat? Two years straight I’ve had gallon milk jugs with moss growing inside…not a good sign for soil health or seed germination.
winter sowing results- mold can be an issue inside opaque milk containers. This has not been an issue using clear containers like 2-liter soda bottles.
Seeds Rarely Sprout in Moss
  • Moss-filled containers can recover (somewhat) after the lid is removed and they’re placed in direct sun. Still, this container is a major disappointment.
Winter Sowing Results- If your winter sowing containers grow mold, take off the lid and set seedlings in direct sun. You might still be able to salvage a few milkweed plants.
Overcoming a Mossy Start
  • Scatter the milkweed seeds generously when creating your winter sowing container…it’s easy to pinch off overcrowded seedlings and it increases your odds of giving birth to a full patch.
Growing Milkweed Tip- Never rely on one germination method to start all your milkweed seeds. Our purple milkweed seeds had a high germination rate with cold moist stratification, but failed miserably in our winter sowing containers.
Starting Seeds Inside Saved The Day

Remember that winter sowing milkweed seeds is just one of many methods of propagating milkweed plants. As I always say, never put all your milkweed seeds in one basket. Happy sowing…and growing!

For more info about Springing your Milkweed Seeds, please read the comments below:
Share the Joy of Butterflies

Similar Posts


  1. Living in central
    Connecticut, when can I expect to see flowers on my Giant Milkweed?

    1. If you started from seed, it will probably be next year. Plants started from stem cuttings in spring should be close to blooming in most regions.

  2. Hello Tony, I have been raising monarchs for about 10 years. I wonder if you have come across this problem before?
    In the past two years I have run into a problem with… I think it is my milkweed which has me puzzled. The milkweed looks healthy, the butterflies lay their eggs, I collect the eggs almost immediately, I have the tubes to keep the leaves fresh, basically I go through all the cleaning process. My results are so sad. The caterpillars grow a couple of days and then they look like they are broken in half. I had one caterpillar grow very well for 6 days and then did the same.
    This happened last year where I collected 15 to 20 eggs and after a couple of days they all died., I went through a process of bleach and water wash that I saw on the web, however the results were the caterpillars grew and went to the next stage but then died.

    On the bright side, I will go and hunt caterpillars on rural sideroads and have wonderful results.
    My question is, could my milkweed have something wrong with it? I see monarchs everyday in my garden and they keep laying eggs … have you heard of this before?

  3. I saved some A. tuberosa seeds and stratified them this past winter. When they germinated I potted them in small pots. I put them in a tray on a high shelf and forgot them – the soil dried out and when I found them, they were fine and looked like A, tuberosa. As they have grown, in the sun, and the greenhouse, the leaves have widened until they resemble A. exalta. Has anyone ever had such a thing happen? I hesitate to plant them out as I have no guarantee that I didn’t collect A. exalta seeds although I intended to grow more A. tuberosa and had every reason to collect those seeds. Any thoughts?

    1. hi Linda, when tuberosa gets more moisture, the leaves will be slightly wider. I would continue to grow them and see what happens. You’ll discover the answer when they finally bloom….

  4. I started my seed by leaving it out in the garage for the most part of the winter. I brought my milkweed seeds in, put some on a coffee filter and soaked the coffee filter with water, put them in a container and onto a heat mat and they popped really good. I put the sprouts in containers of dirt. But i like the pop bottle idea and will do this next year. Its been slow growing but some are doing well. Yesterday, i was looking at my last years milkweed in the garden my milkweed is popping but none of it is more then a foot high and lo and behold i found 2 eggs on this young milkweed. I just saw my first two butterflies of the season in the past 2 days. 🙂 Soon i will be using my milkweed i grew, in my butterfly houses 🙂 Thanks for the tips. 97 in the NW metro again today. Too hot tooo soon this year. lol

  5. Thanks Tony, l planted two clear plastic containers with common milkweed
    last year’s Super Bowl day.
    I followed your instructions to a tee.
    And now I’ve got two containers chalk full of healthy milkweed.
    I also planted two trays of common and two trays of tropical indoors.
    All are doing fine but if l ever need anymore common milkweed I’ll fall plant it
    outside not indoors.

    1. congrats on all your new spring seedlings Brian…yes, fall planting plants and/or seeds is an easier way going forward.

  6. Just purchased some Calotropis gigantea seeds not realizing the timetable for germination. I live in central Connecticut. My question now is what would be the best month to begin the growing process.

    1. Hi Donna, you can start them now and overwinter a couple containers indoors…you should have have flowering plants next season. Before you plant seeds, I would soak them in water for 24 hours to speed up germination rate:

      Calotropis Gigantea

  7. Tony you mention taking stem cuttings from tropicals and then overwintering them indoors. Just wondering, wouldn’t that enable the OE virus to overwinter as well on the tropicals you raised that way?

    1. Hi Alice, whenever I bring plants indoor I cut them back to encourage new growth. If you’re still concerned about pathogens you could spray down the cut back plant with a hydrogen peroxide or bleach solution (9 parts water, 1 part bleach) mixed with water.

  8. I put my milkweed seeds in cardboard egg cartons so that I just tear off each ‘egg’ segment then plant the whole thing in the ground/large pot and do not disturb the roots. My main reason for the seedlings is that when the cats demolish the existing plants, I need more food without eggs so my babies can grow. My garden plants are already in full bloom and I already have several stages of instars cats… but they seem to be disappearing. New eggs keep reappearing with all the butterflies I have. I saw a comment on lizards eating the cats…I didn’t think that was the case…what other predators do I need to keep an eye out for? do the red and black ‘Japanese beattles’ eat them?

  9. I spotted my first winter sown Common Milkweed sprouts in 2L bottles today in MA (4/28/18). We are finally getting spring weather.

    1. Congratulations Nancy! Yes, spring has been slow to come to many northern regions but things are looking better…

  10. How much direct sunlight is required by milkweek? I planed a butterfly garden w/o planning for sunlight. A fence (to the East of garden)blocks most sunlight. I large tree to South blocks alot of direct exposure. The house to the West bocks late afternoon sun. Is it time to dig up the planted plants and try to find more time in direct sunlight?

  11. I had great success with inside cold moist stratification using the refrigerator coffee filter method…about 95% germination. The seedlings are now growing in an indoor plastic greenhouse with 2 seed grow mats on the bottom shelf since my house is usually 63 degrees. I want to plant the milkseed seedlings in 2 large corrugated steel trough-like raised beds n my backyard. Lots of sun but north exposure. The depth to ground level would be about 24 inches. My question is would it be best to add sand to an organic soil mixture for the beds and, if so, what proportion of sand? The left over seedlings will go in a sunny patch in a pasture in front of a small woods after I get them a little taller and stronger in pots.

    1. Hi James, we don’t typically add sand, but have mixed in topsoil before (which contains sand) and compost but not sure of exact proportions since we’re amending the soil (depends on current soil conditions). Putting the seedlings in two different areas is a good idea to see if they have a microclimate preference. good luck with your milkweed!

  12. can i put milkweed seeds from last year’s crop in good soil in yard and water frequently. is that enougj for them to startn grow?

  13. Hi Tony,

    We tried the container method this winter with a couple gallon containers and several 1/2 gallon milk jugs. we found the smaller ones worked better for us. We did get about 12 plants from this system. we forgot to drill the holes in the bottom, but still we were able to get seedlings. Now I have moved them to our little green house until they get a little bigger. That was fun. Thanks for all of your information. Next year going to use just smaller size and moving them to a site in the garden where they will get a little less moisture.


  14. Hi Tony. Tried your container technique using 1 qt deli containers with holes poked in lids and bottoms. Buried in snow and 1 month ago took off lids and placed in my 6′ x 8′ greenhouse. This morning I transplanted seedlings into 72 cell/tray size planters. So far 18 each of A. speciosa, A. Exalta and A. purpurascens Some common and swamp to transplant. Also hade success with Joe Pye Weed,Royal Cachfly and Cardinal flower

  15. For a better transplant, plant the seeds inside containers of rolls of paper,
    In this way I skip the step of breaking some root

    1. Hi Patricia, if you have a good germination rate the soil eventually becomes a fibrous mass and it’s easy to separate the plants without breaking stems.

  16. I sowed my milk weed seeds before the 3 day down pour in pots out side now its fine
    weather but no sign of plants did they get to much rain? Thank you

    1. Hi Carole, this is just recently? Milkweed seeds can take weeks to germinate. Depending on the species some will need cold treatment before. When asking about milkweed please post the specific species since they have different growth/propagation requirements. Thanks!

  17. My Joe Pye, Purple Coneflower, and Swamp Milkweed seeds all started sprouting in my jugs a couple of weeks ago when we had that weird warm spell. Then the temps dipped into the teens so I brought the jugs inside. The temps are finally creeping up above freezing again, is it safe to put the jugs back outside as long as I bring them in again if sub freezing temps are expected again?

    1. Hi Les, I would set them back outside…the seedlings are protected inside the jugs, even if it dips below freezing

  18. Thanks very much for this information! Question: I’ve read where it’s hard to transplant milkweed seedlings as they resent any disturbance to their roots. Have you experienced this when separating and planting out the seedlings in your containers?

    1. Last year I ordered and transplanted half a dozen purple milkweed seedlings for my location in southern New England. None of them survived to this year – they didn’t seem to like being transplanted – so I’m debating whether to try that variety again or a different one.

      1. Hi Kay, our purple milkweed hasn’t started coming back in Minnesota…I wouldn’t give up yet.

  19. Hello Toni, I found this to be the best way to get seedlings from milkweed because mine are two inches tall as I planted a few weeks after you. Yesterday I transplanted them to larger containers as we have possum & raccoon that like to go after small plants. I also tried planting many seeds indoors with the heating mat & it seems the middle of all my flats seeds got burned & never popped out–don’t believe I’ll try it again. So happy to know about winter sowing.

  20. I used the milk jug method and found it worked best for my swamp milkweed seeds. I only managed 3 common milkweed seedlings using that method so I’ll try the soda bottles this fall. Last fall a coworker gave me two clumps of milkweed from her patch. When I checked a couple of hours ago, there were six tiny caterpillars munching away! It’s encouraging to know that the butterflies found the plants. Now I’ve got to expand the patch so that there will be enough for the caterpillars to eat.

    1. Hi Erica, I found that spider (viridis) and swamp were ok with wet feet. I think most other varieties will perform better in the soda bottles. Congrats on your monarch visitors…always feels good when you start see signs of success in the garden!

  21. Last year was the first season that I tried to raise Monarchs. A small start hope to build from there. I gathered common milkweed seeds from neighboring fields and planted them in my own small field last fall. So far about 80 percent germination. Last season I was in email contact with a lady in Pa. who made enclosures out of mosquito netting or similar. She released in the neighborhood of 700 Monarchs.

    1. Hi Ray, I hope you enjoyed a successful first year of raising monarchs. It sounds like your friend had a fantastic season out east. These are the cages that we use:

      Monarch Caterpillar Cages

      Congrats on all your new milkweed plants!

  22. How nice to read so many replies! I had a great last season with the release of 98 monarchs. We had a mild winter here in Florida so all my plants are still doing well with many of them flowering. This is the time of year I do stem props. A mature plant will root in water in no time. Just make sure you pinch off all the leaves. We have had a week of rain and I am in battle with severe spider mites and our famous yellow aphids. Any great answer to control these non wanted visitors ?
    It is always a pleasure to read your information and knowing your passion for the Monarchs always brings a smile.

    1. Hi Jeannie, we also stem cuttings of tropical. I agree they are a much better propagation method if you have mature plants to take cuttings from. We also take cuttings in late summer and overwinter indoors.

      Spider mites can be rinsed off with water or cut off infested leaves and discard. You can also try insecticidal soap, but make sure to rinse thoroughly for future monarchs. Here are 8 ways you can stop aphids from taking over your milkweed:

      Aphid control for Milkweed Have a fantastic season and good luck with your stem cuttings!

  23. Hi Tony,
    I live in Lake Elmo, MN on 3 acres. My main problem is gophers. They love milkweed, Joe Pye weed and Liatris. These are my favorite plants. They eat them underground over the winter, so I never know what I am going to have in the spring. It is hard to have enough milkweed. I am not going to kill the gophers. I want to live peace fully with them. I do grow Tropical Milkweed to put into pots. That does help some. I may have to grow more in pots this year. Do you have any suggestions?

    1. Hi Bonnie, this video goes over some options you have for dealing with gophers. Containers and raised beds might be your best options. There may also be a species of milkweed they are less likely to eat, but you would need to experiment to see what works. Good luck!

      Dealing with Gophers in the Garden

  24. Hi, I really enjoy all of your tips and advice, thank you so much. Here in beautiful sunny Southern California it requires almost no effort to raise monarchs. The seeds simply fall off the bushes and replant themselves. I have little cats everywhere. Thanks to your advice I’ve planted many monarch- friendly plants nearby as well. The only problem I’m experiencing is that my caterpillars are being eaten by predators. In your opinion, would a simple, shaped shelter made of chicken wire do any good at all? This little habitat is in my front yard and I can’t really add structure that would be unsightly. Thank you again.

    1. Hi Eden, there are many monarch predators, and it’s estimated that between 1-5% survive outdoors. We raise indoors in our 3-season porch where the monarchs are exposed to outside temperatures, but not to extreme winds/rain/sun. Chicken wire won’t keep out monarch predators and it won’t keep small monarch caterpillars inside. These are the cages we use:

      Monarch Caterpillar Cages

  25. Hi Tony,
    This has been a great season. I’ve released about 30 Monarchs and there’s more to come. Last year was my first season and the lizards got most of my caterpillers. This year I built an enclosure and they have done very well. I have had no luck growing new plants from seeds so I just buy more plants. I’m trying to root some new plants by putting stems in water. We’ll see how this goes. Thanks for all of the tips. This is really a lot of fun.

    1. Hi Skip, congrats on outsmarting those pesky lizards and saving more monarchs. If you’re rooting tropical, you should find it to be a much simpler method of propagation…good luck!

  26. My husband and I built a butterfly house last year using 1/2 of my raised garden bed. The milkweed is growing nicely inside within the plastic containers and I also have some plants from seeds I started in the house. Thanks for all the great advice.

    1. Sue, it sounds like you are well on your way to a fantastic butterfly garden. I am glad the tips are helpful and look forward to hearing about your garden this season.

  27. I was wondering if I can pinch back the seedlings to have them bush out . They look rather spindly. They are about 3inches high now.

    1. Hi Carole, this is about the height you can pinch them back if they have at least two sets of leaves. You can always experiment with a couple to make sure they respond well to being pinched back. Good luck with your seedlings!

  28. Hi Tony,
    I love all the tips you have. I live in south east TX. I did no have a good year last year with the Monarchs. I know for sure that a lot of the nurseries in the area spray their plants. Most of my plants over time are from seeds I have collected from my plants over the years. This year is am starting off really well compared to last year. I have at least 25 cats so far. To survive over the winter, I place my plants in an outdoor plant house that my husband built. I cover in the winter and place a warm light inside. It took me a couple of years to figure this out. I was not having much luck and did not have the pace to keep them inside my garage. I do place a few however when needed inside and place a warm heater near my plants. I think the much needed rain we have had over the past winter has gotten me off to a good start as well. Last winter was much drier. I also keep several plants in the ground in my beds. Praying for a successful year for all. Thanks for all of your tips. They are a big help.

    1. Hi Angie, I’m glad you were able to figure out a way to overwinter plants…and adequate rainfall is always helpful. Good luck and keep us posted as the season unfolds!

  29. I planted my seed from last years crop in Jan 2015.
    They are all about 2 – 12 inches high at this point.
    Lookin good.
    I fenced my Milk weed garden this year – as last year the rabbits got to a lot of the plants.
    I can’t wait to see my first Monarch.

    1. Hi Sare, glad to hear things are going better with your milkweed this season. Good luck with your seedlings and hopefully your first monarch arrives soon!

  30. Hi Tony

    I only did the tropical milk weed because I have the common milkweed that I planted last summer and seeds from swamp and purple that I planted last year also, so this year I successfully planted tropical milkweed and the only thing I regret doing was using the lights because when I set them out little by little the’re leaves got crispy which didn’t look good so next time I will just put them in a sunny window instead. It’s a good thing that I didn’t put all of them out so I only lost half.

    1. “the only thing I regret doing was using the lights because when I set them out little by little the’re leaves got crispy”

      I presume you mean you started them under lights indoors?

      They were not hardened off properly, most likely when you moved them outdoors.,

      That is a shock. They need to be in a shady area for a while, then more light, then more light. When you take a seedling tray out and place it in full sun, you are asking for trouble. Same for any tender perennials that you over winter indoors. Even if they were in a bright window, it is stressful to move them to outdoors full sun.

      Hope this helps.

  31. do you put up any kind of wooden structure near your milkweed plants for protection of the cats when they pupate?

    1. Hi Bill, I typically bring in large caterpillars and let them pupate in a mesh cage. However, structures can be helpful too like statues or garden plants with large sturdy leaves…basically anything you can think of that’s sturdy and not harmful to the environment would be a good idea to try. Good luck!

Comments are closed.