How To Cold Stratify Seeds with Cold Moist Stratification, Dry, or None?
Cold Stratify Milkweed Seeds to Increase your Germination Rate
Most milkweed species planted in North America need a cold moist stratification to encourage spring germination. Cold moist stratification is a technique used to simulate the real-world conditions a seed would receive outdoors after the frozen winter gives way to a warm, wet spring.
We haven’t started many native seeds indoors because we’ve been the lucky recipients of a magnificent common milkweed patch, compliments of Mother Nature.
When we have started native seeds indoors, I’ve simply put the seeds in a plastic bag, then placed them inside a refrigerator for about a month. I’ve never had a problem starting common, swamp, or butterfly weed seeds in this manner, but have only done this on a small scale so I’m uncertain how effective this is compared to a cold moist stratification.
Today, I’m here to conduct an experiment that might shed some light on what the most effective stratification method is for milkweed seeds. These are the first simple steps for milkweed cold stratification…won’t you plant along?
WET Cold Stratification VS DRY Cold Stratification
1. Gather your supplies
Native milkweed seeds, coffee filters or paper towels, plates, plastic sandwich bags, food containers.
2. Soak your filters
After you have soaked a filter under the faucet, shake out excess water and lay it on a plate.
3. Fold Your Seeds
Place the seeds on the wet filter, then fold the filter over them so they stay inside.
4. Bag your seeds
Place your folded filter inside a plastic sandwich bag and seal the bag shut.
5. Containerize your seeds
Place the sandwich bag inside of a food container and secure the lid.
? If you limit each container to one species of milkweed, you should be able to place the filters directly in the sealed containers without the plastic bags.
6. Refrigerate your seeds
Put them in a safe place inside your refrigerator for about a month.
7. Plant your seeds
Take your seeds out of the refrigerator and remove them from the coffee filter. Plant them in a seed starting tray or a pot, or sow directly outdoors.
Cold Dry vs Cold Moist Stratification Results
Asclepias Tuberosa (Hello Yellow Butterfly Weed)
100% of the Cold Dry Stratified and 92% of the Cold Moist Stratified (1 seed didn’t sprout) have germinated. All the Cold Moist Stratified seeds sprouted first, starting after just two days. The cold dry seedlings were a few days behind, but all plants from both treatments look healthy and continue to grow.
Cold moist stratification worked well using a wet coffee filter sealed inside a plastic baggie. The filter/seeds were still wet a month later and none of the seeds sprouted prematurely inside the refrigerator.
Asclepias Purpurascens (purple milkweed)
I only tried cold moist stratification on purple and 75% of the seeds (3 didn’t sprout) have germinated. I have had a problem starting purple seeds using dry cold stratification in the past. I consider this a huge success.
Gomphocarpus fruticosus (swan milkweed)
I was curious to see how seeds from a warm weather variety would be affected by cold treatment. The germination rate was 0%, although I think seed quality was a contributing factor.
I was able to get 7 seeds to sprout earlier by soaking the seeds in warm water before planting.
Recently, we tried ‘cool’ treatment by spring sowing fresh swan milkweed seeds and had great success.
Asclepias tuberosa (butterfly weed)
Want to see something totally amazing? Community member Gwendolyn J. sent me this photo of Asclepias tuberosa seeds she started in a container of water! She was also able to do this successfully with tropical milkweed seeds.
Gwendolyn’s Steps to Milkweed Seed Germination in Water
1. The milkweed seeds were not cold stratified beforehand.
2. I used plain room temp, rain water, I guess about a cup in small food containers, (plus a tablespoon from a gallon of rainwater mixed with 1 cup 3% Hydrogen peroxide). I spray it on seedlings and their soil to kill fungus gnat larvae.
(note~ if you soak seeds for 24 hours in a solution of rain (or distilled) water + hydrogen peroxide it will soften the seed coat and give the seeds more oxygen for faster germination.)
3a. The containers are also under lights for 14 hours a day and room temp. is 70° F.
3b. If room temp is below 70° F use a heated seed mat under the containers
4. The milkweed seeds began to germinate within a few days.
5. I pour them out on soil when I start seeing roots, then sprinkle a little soil over them.
(suggestion~ after milkweed seeds have germinated in water, we water the soil, then plant the seeds so the leaf is above the soil to receive light. You could also plant the milkweed seedlings in a pot if you want to give them more time to grow before transplanting to their final resting place.)
Gwendolyn, on behalf of our community, I would like to thank you for sharing this surprisingly simple way of starting milkweed seeds!
Honeybees can have a hard time with milkweed, sometimes getting their legs caught in the flowers
Hi Larry, I have seen flies and small white butterflies get stuck in common milkweed blooms, but never honey bees, and we see them often in our garden…
Thanks for this information. I’m using that to unlock the dormancy of my bog myrtle seeds. I got in an ounce of bog myrtle seeds and one package. One ounce is a lot of tiny seeds. We washed them in detergent and then rinsed then to death then put them in a chemex filter and put them in cold storage for 3 months. We also put the dry seeds in cold storage for sowing in the fall. I didn’t take the wax covering off of these.
However, my gardener is now suggesting we use your methods to spread our milkweed. Thanks.
THANX!! FINALLY got sprouts this year!
Hello! I have some milkweed seeds I happened across at my parents farm. They have been outside all winter. Would I be ok to go ahead and plant them in peat pots right now for eventual planting outside once the seedlings are big enough?
Hi Michelle, I would probably soak them in water for 24 hours before planting in peat pots to soften the seed coat and increase germination rate/speed…good luck!
Greetings from Down under
I have put some Asclepias Tuberosa seeds in damp paper towel bagged and in a container, in the fridge for two months but no sign of life??? From what I saw on YouTube the seeds should be sprouting??? Do I assume this has been a failure or is there anything I can do to retrieve the situation? Thank you, your advice will be most welcome.
Hello Irene, it’s not going to germinate inside the refrigerator…I would take them out and plant them.
I’m in the South Shore of Milwaukee WI zone 5b along Lake Michigan and always have tons of Butterflies, Birds (not to mention other wildlife). Question about just putting all my perennial seeds in the garage (suspended in a small hammock from the ceiling, all seeds in original or homemade paper envelopes and all seeds then in rubbermaid sealed container – mice!). Anyway will this be ok for cold stratification of most perennial seeds including common milkweed? I do know that some might also need scarification (done between 1 sheets of xxxfine sandpaper). I have a ‘winter garden’ in an upper large of my home with shelves/grow 8-4 ft. grow lights. East/West windows, water from the old kitchen sink that doubles for a nice potting center, and everything seems to grow well up there – including potatoes all winter long. Our last frost can be as far away as June 1st, so starting the seeds by the 1st of March so I have some stronger plants to go outside by Memorial Day weekend – my favorite planting weekend (with helpers for this slowing Senior).. dry stratification in garage work ok?
Hello Kathleen, dry stratification will work…the moist part softens the seed coats which increases germination rate + speed of germination
I am a complete newbie! I am sorry if I’ve missed this, but I have harvested my seeds (zone 8) – now when should I plant them to have them ready for spring?
I must admit I’m confused…
start inside/direct sowing….
Hi Kathy, please check our milkweed page to find propagation methods for your specific milkweed:
Milkweed for North American Gardens
Hi, I am planning an Earth Day booth next spring. I am gathering common milk weed seeds now to put in little packets to give out. Should I store those seeds in the fridge? I could try to explain the how to do this but I expect to be dealing with a lot of little kids. I HOPE I catch their interest and they will in turn try and grow more milk weeds for Monarchs too.
Hi Rain, if you are giving them out in late April, probably best to cold stratify so they can plant soon after…
Didn’t have any luck with starting cuttings from my (purchased as a starter plant this spring) Tropical M. Weed. Usually I have problems with damping off starting from seed but must have collected 100’s of seeds from the pods in the last few weeks (with more on the way!) so might as well try again.
Would watering the seedlings with peroxide water help or would that “burn” very young plants?
Hi Vickie, you can also try using rooting hormone to plant tropical milkweed cuttings directly in soil next spring.(if you overwinter a plant)
As for using hydrogen peroxide, I’ve never experienced any harmful effects to plants at any stage of development. it kills pathogens, puts more oxygen in the soil, and wipes out fungus gnat eggs
I just watched your video for separating the seeds from the fluff. Unfortunately, you mentioned that the fluff should be thrown away afterward. Instead, consider tossing it outside for birds and other critters needing to line their nests.
Your site is incredibly valuable. I’ve consulted it numerous times when researching something about my monarchs. Thank you very much.
I think it makes sense the water sprouting method. I do this all the time with wheatgrass seeds that I grow for my cat (and me, when I’m feeling ambitious to juice!)…I keep them in water for 1/2 day then in a sprouting jar, rinsing / draining 2-3x a day until they start sprouting (2-3 days). Then plant and keep moist until they start taking root. I would think this should work with many types of plants, although I don’t know about this cold stratification for native plants to us northerners…
In Minnesota, cold moist stratification increases the speed of milkweed seed germination and also the germination rate. If you want winter to take care of this for you, you also have the option to:
fall plant seeds
water stratification works especially well for Asclepias tuberosa, and will work to some extent for most varieties…
Hi. Have been reading and wonder where you get seed for the purple milkweed. I live in Iowa. Thanks for all the info. Sue
Hi Sue, someone was kind enough to gift me seeds a few years ago, but I bought some as plants the monarch festival at Lake Nokomis (Mn) in September. Check out the suggested stores section on my milkweed resources pages for seeds and possibly plants:
Suggested Milkweed Vendors
I’m so glad I found this page!
I’ve had great success with Gwendolyn’s method for Asclepias tuberosa. Nearly 100% germination.
I had 100% germination with Silene regia (Royal Catchfly)!
congratulations Amy…I was amazed the first time I tried it too! Good luck with your new seedlings…
Were Gwendolyn’s seeds wild or pre-packaged? I just bought a large assortment of milkweed seeds and was wondering about the larval gnat thing…
Hi Rita, I’m not sure what you’re asking? fungus gnat eggs/larvae are in soil so there would be no difference between using wild and prepackaged seeds.
Do you think water germination would work with Gomphocarpus fruticosus or Gomphocarpus physocarpa? I am starting my butterfly weed that way this year. I thought I might try it with the Swan milkweed, and the Family Jewels. Just wondering if you have tried it or if you have heard of anyone else trying it with those varieties?
Hi Terry, yes…it will work with both. I have a photo here:
Swan Milkweed water stratification
Do you have any additional information or comments about Gwendolyn’s method of seed germination in water? I am trying this method for the first time with A. tuberosa, tropical, and Oscar. What is the usual time for roots to be seen? Thanks for sharing this technique…
Hi Sandy, just what’s posted. I’ve tried this propagation technique successfully and I think the first seeds started germinating in under a week. I’ve also gotten reports from others who have tried this successfully…good luck!
Hi, Tony, I am thrilled to find your site.
I live in CT and have always had some incarnata and tuberosa in my flower bed, but my Monarch visitors had all but disappeared. So last year I got inspired to create a registered Monarch way station here. Started a bunch more incarnata and tuberosa MW from seeds, and included some syriaca and curassavica as well. Found out, after the seeds arrived, that I really needed to stratify the perennial varieties, but it was already March, so I just planted 4 to a pot hoping some would germinate. Used a grow lamp and a heat mat, and, hooray, I got about 50% germination rate on the perennials, except the syriaca. I planted about 40 MW in my garden and also gave away seedlings to people who were interested, and gave several talks. The tropical variety grew and bloomed beautifully, and I saw 4x the monarchs and caterpillars I’d seen in prior years. The other varieties will bloom this year, I hope! So, now in year 2, I’ve talked my town’s community garden into adding a butterfly way station too, which I am providing seedlings for. I am refining my seedling technique, doing cold moist stratification of the perennials right now, but not the tropical, which has already sprouted.
My first question is, do I keep the grow lamp on 24/7 on the curassavica sprouts, until it is almost time to plant them outside (May 7 ish around here), including a little hardening off period before they go in the ground? I am also planning on potting them up when there are about 4 sets of real leaves.
Also, what would you say is the ideal age for a perennial or annual seedling that’s been started indoors to be moved outside?
e.g. this year my plan is, that my perennials ( I’ve got syriaca, tuberosa, exaltata, incarnata, vertillicata, and purpurascens) will be sown inside about 8-9 weeks before they move outside, and I’ll be potting them up midway thru that period. The curassavica will have had almost 10 weeks indoors, before outdoor planting past our frost free date. Is that a good time frame, in your experience?
Hi Alice, congrats on your butterfly garden success and helping start your local community butterfly garden. If you’re growing tropical milkweed under grow lights, 10-12 hours a day should be sufficient. If the leaves start turning red, they are getting too much light. Once you have mature plants, you can overwinter a couple indoors and take cuttings to start new plants, which grow faster than seedlings.
I move plants outside after the final avg frost date. Last year, I started ‘spring sowing containers’ in early March…this works well for starting tropical milkweed and is less work on your end:
Spring Sowing Containers
Our goal is not to have mature tropical milkweed at the beginning of the season because that’s when they favor the native/perennial varieties, but to have it start peaking in summer when the natives start to fade. Your time frame is fine for starting indoors. Starting 1-2 months before avg final frost (or spring sowing) is what I would recommend for northern regions.
For the perennials species, we utilize winter sowing because the germination % is higher with cold stratification:
Winter Sowing Milkweed
If you’re starting plants inside, put them in shadier conditions when moving outdoors and gradually expose them to more light. Good luck with your gardens!
Tony, thanks so much. For perennial milkweed seeds (already stratified) to germinate best, do you recommend using a heat mat once they are sowed in seed flats?
Hi Alice, I use the heat mats on the perennial seeds too. It speeds up germination…
Put swamp milkweed seeds in soil in containers in fridge the 1st of February rather than outside and planned to leave for a month. Then assume I set outside in containers for awhile before planting in ground. Just checked and didn’t see anything yet. Soil seems moist so haven’t watered. Am I going the night direction? Am in Tulsa, Oklahoma and weather has been up and down for awhile.
Enjoy your tips. Thanks for your help.
Hi Lana, are the seeds in your refrigerator or did you move them outside? The seeds won’t germinate while they are inside the refrigerator.
Just a note about growing A. curassavica (tropical milkweed). This milkweed fosters the possible transmission of the protozoan ophryocystis elektroscirrha (OE) increasing the likelihood of monarchs becoming infected with this debilitating parasite. To read more about OE and tropical milkweed see the website Monarch Joint Venture at monarchjointventure.org
It is always best to grow milkweed native to your area. Monarchs are in dire need of our help and I feel it is best to stay away from growing A. Curassavica to keep Monarchs healthy.
Hi Yvonne, tropical milkweed is an invaluable milkweed species for monarchs throughout the US and Canada, and there are monarchs using it now in their overwinter grounds in Mexico.
In continuous growing regions like Florida and southern California, there are potential issues if the plants are not cutback periodically, but this is not an issue in other regions….yet this misinformation still spreads like wildfire.
As for ‘always’ planting native, native plants are the cornerstone to a successful butterfly garden, but non-invasive annual plants can help take you garden to the next level. Monarchs are not native to one region, so why would they only favor your native plants? Here’s more info on tropical milkweed:
Is Tropical Milkweed Killing Monarch Butterflies?
Will Asclepias Curassavica seeds germinate after being frozen?
Hi John, freezing temps will reduce the germination rate but some seeds will survive. We even get tropical milkweed seeding up north in Minnesota.
I just put some A. Tuberosa andLupine seeds in the fridge for cold moist stratification. I’m not sure if you’d know for the Lupine, but would it be too late to start the butterfly weed seeds inside in 2 weeks to a month? Around how tall should they be before I transplant them outside?
Hi Anissa, A. tuberosa seeds can be started in water if you look at the directions at the bottom of the page
I have the exact same orange butterfly milkweed seeds as Gwendolyn, bought from ebay, and have had NO luck staring them. I will try the water method and keep my fingers crossed! Thanks so much for this post!
Hi Liz, if the seeds are viable, this method definitely works for tuberosa…good luck!
With a very large supply of milkweed seeds on hand (common, swamp, tropical, hairy balls, and butterfly weed), I’ve been experimenting with just how badly I can treat them and still have them sprout in water. Not bothering to cold stratify – – still germinated. Picked from a pod that was exposed to all the elements all winter – – over 10% emerged so far after less than a week. Stored on a shelf for a couple years – – did fine. Thanks for passing along this method. I’ll probably never bother with any other techniques again.
I was amazed when I tried it too…sometime we make things far more complicated than they need to be…lol were you using a heated seed mat or without?
I didn’t use a heated mat. The seeds seemed to germinate fine without one.
Thank you for all of the valuable information you provide to so many of us!
I am in Toronto, Canada (zone 6a) and have a couple of questions:
1. How long can milkweed seeds be stored (dry)and still have a decent germination rate?
2. For a local school, I will be providing Syriaca seeds that have been in CMS for 2 months. The kids will plant the stratified seeds in 500ml water bottles (with the top half cut most of the way, as in winter-sowing), and then place the bottles outside for the seeds to germinate. Do you see any flaws with this plan? Any advice that might increase my success rate?
I welcome any suggestions you might have….
Hi Michelle, we keep seeds about 3-4 years but I can’t give you an exact answer for the germination rates. If you’re not sure about your seeds, try starting a few indoors to test them.
For the school milkweed seeds, that sounds like a good plan! Common milkweed has a great germination rate with cold moist stratification, and the seeds germinate earlier in spring inside the winter sowing containers.
This is my first year growing milkweed seeds & I’ve got several different types of seeds. Since I’ve never before had luck growing seeds I’ve purchased the little greenhouse things & growing mats. My question is your photo Cold Dry vs Cold Moist Stratification Result is that when you actually begin to take the lid of the greenhouse & begin the rotating fan? Everyone talks about that point but what do those of use with no experience know what it really looks like.
Thank you so much for all your words of encouragement to those of us new to this & I even see here in Missouri people/cities are taking up the monarch challenges–I just don’t live in these cities.
Hi Nancy, I would say with the problematic species like swan milkweed or balloon plant start when they’re about 2-3 inches tall. You want to start strengthening the stem before it becomes a potential issue.
I have my first ever native variety seeds stratifying in the fridge now, per your instructions. I also have a few tuberosa, incarnata, and syriaca seeds in water, just to see what kind of germination rates I get. These are all seeds that I collected this past fall, kept at room temp for this very purpose. Will report back when I have results.
Do you know any source in Canada where I can get seeds from? I collected some seeds last year and have them in pods. I collected a few dozen pods and put them in the freezer. Should I leave them in the freezer and plant them in the spring? I hope they sprout. ANy suggestions would be great.
Hi Marina, I’ve never stored seeds dry in the freezer, so I’m not sure what kind of germination you can expect. If you want to give them some moisture you could always put them in winter sowing containers and place them outdoors:
Winter Sowing Milkweed Seeds
There is a link at the bottom of my milkweed resources page for buying seeds in Canada, if you scroll to the bottom:
I tried the “water stratification” with some tropical milkweed seeds… out of 10 seeds 6 sprouted within a week. Pretty good. I haven’t given up on the other 4 yet.
I might try it with some other varieties when the proper time comes.
Thanks for the tips.
Hi Arthur, it definitely works with other species too, but I don’t have a complete list. I will be experimenting more with this next spring. Good luck with your seeds!
Tony, with the Purple MW how long did you use the cold/moist treatment? Also, have you ever heard of putting the wet seeds in the freezer long enough to freeze them a few times during stratification? My understanding is this helps those hard to sprout seeds. Another thing I’ve heard is to soak the seeds following stratification for 24 hours and then planting. Any info on these topics would be appreciated. – Char
Hi Charlene, I cold stratified all the seeds for about a month. I have not cold stratified in the freezer but know that it can be done. I think it matters more that you have fresh, viable seeds than where you stratify them. Good luck!
How did the water method work out for the A. syriaca? Sorry if I just missed it somewhere.
I have not tried the water stratification yet…that’s on the list for late winter/ early spring. I will update this post when i have more info…
I use a slightly different method for germination as deer and rabbit herds have decimated the milkweeds in my neck of the woods! We have A. syriaca, A. tuberosa, A. amplexicaulis and A. quadrifolia in the area. I dig a hole, get an empty water gallon (jug), cut the bottom out of the jug and sink it into the ground. I cut the top so it is still attached but so that I can sow seeds and water if necessary. I then fill the sunken jug w/potting/peat sand mix and sow the seeds. The jug helps to keep seeds moist and when the seedlings germinate it protects them from marauders. Question I have for anyone is…..how do you store the seeds before you start the process of stratification. In other words, it’s mid August now and I’ve collected a bunch of A. amplexicaulis seeds but I don’t want to grow them til next spring so how should I store them? I’ve been storing seeds dry, in the fridge…is this ok?
Hi Lexi, I don’t put our seeds in the refrigerator until I want to stratify them. Typically, I separate the seeds and then let them dry out for a couple days until they are completely dry. Then you can store in paper or plastic bags for later use. I keep ours in a cupboard.
I am going to try the water cup method for sprouting some butterfly weed. I had so little luck with my outdoor stratified butterfly weed (one lone seedling out of 30 planted) that I’m going to try the cold, moist stratification in the fridge, too. I’ll let you know how it goes!
The glass of water works like a charm for butterfly weed seeds! Mine have already started germinating! 4 of the 5 seeds I placed in a glass of water just Tuesday (it’s Saturday afternoon) already have little roots poking out!
Congrats Erica…thanks for sharing and good luck with your new seedlings!
So, if the seeds are “presprouted”, how do you plant them? How deep? This is very interesting. I have some seeds I didn’t get planted so I may give Gwendolyn’s method a try.
Thanks for the great research!!
Hi Deb, I just added this info to the post from Gwendolyn:
“I pour them out on soil when I start seeing roots, then sprinkle a little soil over them.”
Great experiments! I have always read on seed packets wait until all danger of frost has passed before sowing. This year I direct sowed some tropical milkweed seeds in April and they have sprouted. I sure am glad I took the chance considering I live in NE Ohio where the typical planting date is Memorial Day weekend.
Hi Chris, we typically have about 10 tropical milkweed volunteers every season. If those seeds can survive a Minnesota winter, they can survive being planted in early spring. The only issue is that cool soil temps can slow germination and growth. The best way for northerners to start tropical milkweed is through cuttings. Once you have plants, you can start some this fall or next spring. good luck!
Hi Tony ,
I started 12 Milk Jugs with several different kinds of Milkweed and I check today and they all are up at least a inch already .
I started them in February hoping they would be ready for our garden club plant sale in May 13th,I’m so excited .
My common Milkweed is up 2 inches already .
I’m very happy at ‘ Flutterbyacres ‘ !
I admire your commitment Brian, but that seems like a lot of extra work, when you could just have several varieties that peak at different times.
If you don’t want seedlings all overs, cut off some/most of the seed pods before they mature. I do this with our common/swamp every year.
Let me know how stratification works for you in sealed plastic baggies…good luck!
I did not put my seeds into a plastic baggie, I put them into a sealed container and then into another container, but I guess enough air filtered in to dry out my paper towel. Oh well, I guess I’m helping everyone else out by showing them what not to do…
Here’s my plan for 2015. I have both common and swamp seeds in the frig and every Saturday, I am going to pull out 10 to 15 seeds and plant them in 3 1/2 inch cups. Then I am going to strategically plant the seedlings (cup and all) into the garden. Once I have eggs or caterpillars, I will pull the cups out and replace them with fresh seedlings. This way I will always have the freshest possible milkweed for the monarchs all year long, and I won’t risk having hundreds of milkweed plants in my garden next year, just those that I want.
Only two things can thwart my plan. Number one, my inability to follow simple directions on how to stratify seeds, and number two, mama monarchs willingness to lay eggs in my backyard. Here’s hoping that 2015 is a great year for everyone!
Finally my seeds have had their 30 days of wet cold stratification and they came out of the refrigerator this morning. I don’t drink coffee, so I used paper towel instead of a coffee filter. However, when I opened up the container, the paper towel was bone dry.
I was going to do a comparison of germination rates between seeds that had wet cold stratification to those that had dry cold stratification, but I don’t know when my paper towel dried out. If it dried out quickly, I’m probably doing a seed germination comparison of dry cold stratification to dry cold stratification, rats….
I’m sure that some of my seeds will germinate, but my question is, did you use coffee filters in your experiment? Were they bone dry when you pulled them out of the frig, or were they still damp?
Miffed in Michigan
did you seal the paper towel/seeds inside a plastic baggie before you put them inside the container?
I just planted mine on Monday and the filters were still fully wet when I removed them.
Merry in Minnesota 😉
I collected seed pods, I believe them to be Common Milkweed, last fall and kept them in my gazebo over the winter. Last week I soaked them in water for 24 hours, then planted them in a small seed starting greenhouse indoors. After reading this page I am starting to lose hope that they will germinate. What are your thoughts on my situation? Should I scrap this project and try again next year?
Hi Gina, as long as they got a cold stratification (even if it was a dry one) they should have a good germination rate. Soaking the seeds for 24 hours won’t hurt common seeds, and might even have a positive effect on germination speed and percentage. Keep your project growing, and good luck!
This will be our first year growing common milkweed from seed. Right now we have our seeds chilling in the refrigerator (dry stratification), but I will also give the cold moist stratification a try too.
I don’t know how true this is, but I have read that you should occasionally check on the seeds because they could start germinating in as little as three weeks time using the cold moist stratification method?
Only 8 more days until Spring!
Hi Brian, it’s hard to imagine the seeds would germinate if the temp inside your refrigerator is in the mid-thirties. I’ll let you know… I’m not checking mine until I take them out in April.
I have cold moist stratified scores of different types of seed and I would say perhaps 10 % of the various species will start germinating in the fridge. None of these were milkweed.
It is best to check periodically cause if they start to germinate it is best to get them potted up
Am growing ~ 30 types of milkweed this year. Wish me luck 🙂 Have 4 Tropical milkweed plants wintering over in my basement. Scragly but alive.
Hi David, I’m leaving my milkweed seeds in the refrigerator for just over a month…I hope it’s too cold for any of them to germinate before I take them out. If this is an issue, I will update the article. I have used dry stratification in the past.
Wow…30 types? That’s almost double what we have. I look forward to hearing about your garden this season…good luck!
PS. If tropical milkweed doesn’t get enough light it can look scraggly over winter…it recovers nicely when you move it outdoors.
Hi Tony ,
I just got my dormant tropical milkweed and want it to grow fast what will
Make it catch up so that hopefully I can take some cuttings and make even more plants?
I do have common milkweed in the garden from last summer I heard they can take over the yard which I hope happens this season, it was a starter plant I bought online…I only hope that I have enough milkweeds to attach a monarch or any butterflies for that matter.
Thanks for all your videos,
Hi Helen, make sure the plant is getting plenty of light so it comes out of dormancy. I’m not sure about the size/maturity of your plant so I can’t say when you could take cuttings, but tropical milkweed grows fast with warm temps and abundant light. Once the new stems grow to 4″ you can take your first cuttings. Good luck!
Hi Tony 3/14/15
I finally have success with tropical milkweed seed germination, that heating mat helped . I also have a small cfl on during the day from 6:30 am to 9:30 .
I just can’t wait for spring!!!! This winter has been too long for me this year.
great news Helen…congrats!
What is OE ?
Hi Kathy, check out this page for more info on OE:
What is OE?
I too am trying both methods. I was preparing some seeds for cold moist strat when I had a thought to let the fridge handle the cold part and let mother nature handle the moist part this spring. Will be interesting to see how they turn out. I’m also planning on making a seperate bed for the common milkweed seeds to keep the future plants segregated. Looking fwd to your videos this season. Any plans for a gardening/monarch raising TV show in the future? Maybe we’ll see you on HGTV in the future.
Hi Chris, that’s more of a cold “dry” stratification which is what I have done in the past. It has worked well, but I wanted to see if there was a difference if the moisture was applied earlier.
HGTV? We’ll see how my video skills improve over the summer…I’ve got a ways to go, but I’m looking forward to trying some new things .
Keep us posted on your milkweed…
I have been getting several pods and saving the seeds, from the Tropical Milkweed in my butterfly garden. What do I do now with these seeds to keep them. This is the first time I knew about gathering seeds. I am a “newbie” at raising Monarch butterflies – this is only my second season.
I released 4 Monarchs yesterday and have 2 more that will be released today and 2 more chrysalises that should eclose maybe today. And I have 3 more chrysalises that aren’t ready. I did have a butterfly eclose yesterday that had OE which I isolated. A little later another one eclosed and also had OE. I isolated that one also. In the end they were euthanized.
I am very excited about raising the Monarchs. It is a learning experience and I am enjoying every moment!
Hi Judy, tropical milkweed seeds can be kept in a paper/plastic bag in a cupboard or drawer. They don’t need any cold treatment before planting. This is how you would start warm weather varieties of milkweed:
Starting Tropical Milkweed Seeds
Best of luck in your second season raising monarchs!
AAARRRGGHH I wish I had realized this sooner this year !! I am sending seeds to my FB gardening friends in the 39 states that it will grow (syriaca) and I didn’t even THINK about them needing stratification … they have been in my cold car all winter here in Northern Illinois … Dear Abbey, do you think they will germinate ???
Hi Holly, Abbey thinks cold treatment in a cold car in northern Illinois will make a decent cold dry stratification. And if they are fresh seeds from last fall, the germination rate should be high, assuming the seeds are fully mature…
Love the video, nice addition to your posts, thanks
you are too kind Ruth 😉 I am really diving into video this season, so the videos will improve over time. Thanks for your comment!