Starting Milkweed Seeds Indoors Part III

The Final Results Are UP

It’s been just over a week since I started my annual milkweed seeds and it’s time to report the results. If you haven’t read parts 1 and 2 of this seed starting journey, click the links below so you can start from the beginning:

Starting Seeds Inside I (Why Should You Start Seeds Inside?)
Starting Seeds Inside II (Discover My Secret for Lightning Fast Seed Germination)

2014 Update

      • 8 new Asclepias physocarpa (balloon plant) seedlings. The balloon plant seeds in the smallest container germinated first….probably because thewarmed the soil faster in a small container.

    • 3 Giant milkweed seeds soaked overnight in water germinated…our first ever giant milkweed seedlings.

Asclepias Gigantea (Giant Milkweed) Seedlings Started Indoors

    • None of the unsoaked giant milkweed seeds germinated…hoping they will with more time.  Soak your annual milkweed seeds!
    • Next time, I’ll use smaller containers orto enhance heat effect (not gallon milk jugs).

  • Sprayed seedlings with hydrogen peroxide mixture I’ve been using on overwintering plants. Plants seem to respond well to h2o2!
  • Satisfied with these results…just not sure where I’m going to put all the balloon plant milkweed, since we already have 3 large plants.
  • Will update this section with any further developments


This year’s results have been a “mixed bag”, so I’ll report on each milkweed species:

1. SWAN SONG: In 2012, I started goose/swan milkweed seeds (Asclepias physocarpa) that I purchased online. I enjoyed great success and all 7 of my plants eclipsed 7 feet! In the fall, I was able to harvest seeds from them to use for this season. Here are the final results from my gathered seeds:

  • 10 seeds planted
  • first seed germinated after 4 days
  • 100% germination
Goose Plant Milkweed Seedlings after just one week
Swan Song

I’m happy I collected seeds last fall. It certainly paid off this season, and those seeds should be viable for years to come!

2. TARNISHED CROWN: Some weeks ago, I made an “impulse” decision to grow giant (or crown) milkweed (Calotropis gigantea) as an annual. This is native to warm weather regions including Africa/India and commonly used by Hawaiian monarchs. None of my regular sources had these ‘hard to find’ milkweed seeds at the time, so I took a chance on an unknown vendor. The seeds I purchased looked old and immature (kinda like mini Benjamin Buttons), but I’d never grown them, so what did I know?:

  • 16 seeds planted
  • first seed germinated after 5 days
  • less than 1% germination
  • I started the remaining seeds yesterday…hoping I can salvage 2-3 plants for the season out of 50 seeds

I’m very disappointed with these results, but I’m more disappointed that this company is ripping off the gardening community with subpar seeds. If you are thinking of buying milkweed seeds or plants, check out my list of reputable online vendors. (This company won’t be making that list anytime soon.)

3. TREE OF LIFE: When I was researching sources for buying giant milkweed, I came across a similar species of milkweed I had never heard of before. The milkweed tree (Calotropis procera) is also native to Africa but a rare find across North America. AHA!…my experimental milkweed for 2013 was cemented, but would these seeds be as disappointing as the last?:

  • 10 seeds planted
  • first seed germinated after 5 days
  • 100% germination rate
Calotropis procera milkweed seedlings
Little Trees of Life

With over 100 species of North American milkweed, each year brings opportunity for new growth…and more monarchs! While native milkweed species are the cornerstone for a successful butterfly garden, you’ll benefit more from starting annual milkweeds indoors since they need to flower and seed in one season.

If you’d like to take your annual milkweed to greater heights, overwintering indoors is an option we’ve had success with the past few years.

Questions or Comments? Please Post them Below:

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  1. says

    Hi Lila, I typically use a a “seed starting potting mix” because there aren’t large particles that could block root growth. Once there are a couple sets of leaves I’ll add a slow release fertilizer (I use osmocote).

    My annual milkweed varieties have responded very well to the nitrogen boost they receive from this fertilization.

  2. Katerina says

    Thought I’d let you know that about 4-5 years ago and again last year, I bought some blowefloodrs at my local greenhouse. I like to try new garden plants every year. The bloodflower is related to the milkweed but are annuals in our climate zone (North Dakota). Monarchs were attracted to them and I saw several monarch caterpillars, one of which spun its cocoon. I kept a close eye on the cocoon but missed the emergence of the monarch. I saved many seeds from the plants but sent them all to my dad in Idaho. As a family, we collected butterflies during my childhood and my dad is passionate about helping them out when he can; due to the lovely progress of civilization , natural habitats of insects and other wildlife is continually being disturbed and destroyed.

    • says

      Hi Katerina, I think you’re the first person from North Dakota I’ve come across that grows tropical milkweed. It’s an excellent annual for colder zones. Great to hear your family is so passionate about helping monarchs. Happy gardening!

  3. Minnie says

    Hello, I see these are older post and hopefully you are still doing the wonderful job of saving the monarch. I live in the panhandle of Florida and I just begun this challenge. I have order the milkweed plant as well as some seed. Hopefully I can get them t thrive. I have not been as active in my garden this summer as I usually am but plan to jump back in shortly. I thank you for your post and now feel a little more positive about being able to grow the food for the monarch. as well as any other butterfly that wants t stop for a visit. Again thank you and any info would be greatly appreciate.

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