How To Grow Milkweed from Seed

How To Grow Milkweed From Seed

Imagine butterflies happily fluttering around in your garden from flower to flower. You can make this a reality with the simple addition of milkweed to your garden. Not only will you benefit from the natural beauty, but by growing milkweed, you will also be helping a very fragile butterfly species.

The Monarch butterfly caterpillars rely on milkweed exclusively for food. They will not eat anything else. Because of the current re-purposing of land for human use and the widespread use of pesticides, wild milkweed is disappearing from our landscape. If we lose the milkweed, we will also lose the Monarch butterfly.

Growing milkweed isn’t difficult, it just takes a small bit of planning. However, once you see the flowers blooming and the butterflies swarming, you’ll be glad you made the effort. And so will the Monarchs.

Step One – Get The Seeds

Choose a variety that is native to your region if at all possible. These are the ones the Monarchs in your area will like best.

Step Two – Prepare the Seeds (Cold Stratification)

Milkweed seeds will germinate better if they are cold stratified. Cold stratification is a simple pre-treatment that breaks the natural dormancy of the seeds and promotes germination. In short, the cold temperature breaks or softens the hard outer casing of the seed so it can sprout easier. It sounds really fancy yet all it means is that the seeds are kept cold for a certain period of time on purpose.

Cold Stratification can be done naturally by planting the seeds in the fall so they experience the cold of winter. It can also be done indoors.

Indoor Cold Stratification:

You will need milkweed seeds (of course!), paper coffee filters or paper towels, non-paper plates, plastic sandwich bags, and a food container with a lid.
Soak the coffee filters in water and shake off any excess water. Lay them out on the plates.
Place 5-8 seeds in each wet filter, folding the filter over them to keep them securely inside.
Put the filters in the plastic bags, 1 filter per plastic sandwich bag, and seal the bags shut.
Label each sandwich bag with the type of milkweed!
Put the sandwich bags inside the food container and put the lid on securely.
Put the container in the refrigerator for a minimum of 1 month. They can stay there for up to 3 months.

Step Three – Plant the Seeds Indoors

If you are doing an outdoor stratification, you can skip this step. Once the milkweed seeds have been stratified for at least 30 days, they are ready to be planted indoors in preparation for being planted outdoors once the weather is amenable. They should be planted 6-8 weeks before you intend to transplant them outdoors.

Fill 4” pots ¾ full with a good potting soil mix. Add water so it is soaked thoroughly and let it drain through. Place 2 seeds a couple of inches apart in each pot and cover with 1/4” of soil.

Place the pots in a sunny location, preferably in a south-facing window. They need lots of light and lots of warmth. A grow light is highly beneficial at this point to make sure they are getting enough. Water the plants daily by misting the soil. Be careful not to overwater them though. Check the moistness of the soil with your finger. If it is wet, wait a day to water.

In 10-15 days, the seeds should germinate. Be patient, sometimes it takes longer.

Step Four – Prepare Ground For Planting

If you did indoor cold stratification, you’ll be preparing the ground in the Spring for planting. The stratified seeds should be planted after the last frost. If you are doing outdoor cold stratification, you will be preparing the ground in the Fall. For outdoor stratification, be sure to get the seeds in the ground before it snows and while the ground is still diggable.

Milkweed needs light so choose a bright outdoor location. Common milkweed grows well in regular garden soil. If you see milkweed growing in the wild, investigate the soil conditions and you’ll know what milkweed in your area wants.

These seeds are tiny. Choose a clear spot or clear a spot by removing any rocks, mulch, or other plants that may impede the growth of the seedlings. Water the ground thoroughly, letting it soak well into the soil.

Step Five – Transplanting/Planting

Planting Seeds Directly Into the Ground

Make holes 16-18” apart by pressing into the dirt with your finger up to your first knuckle. Place one seed in each hole. Cover the seeds with the moist soil and place a thin layer of straw or leaf mulch over the area so it doesn’t dry out.

If you are planting in the fall, make sure you label your patch well so you can find it in the spring!

Transplanting Seed Starts

It is best to transplant the seedlings when they are around 3 inches tall. If they are allowed to get any bigger, the long taproot will get too disturbed during the transplant and they may not make it. Even when they are 3” tall, they are likely to go through a shock. Sometimes they lose all their leaves so don’t panic if this happens!

Plant the seedlings 16-18” apart in holes large enough to hold the entire root ball. Do not let any roots show above the soil line. Water them for the first few days until it gets established.

Step Six – Care

Once milkweed plants are established, they don’t need much care. They will only need occasional watering, particularly during dry spells or droughts.

Try Our Milkweed Seeds

Interested in growing milkweed? You can find our milkweed seeds here.

We’d Love to Hear from You

Have any questions or tips on growing milkweed? We’d love to hear from you in the comment section below!

2 thoughts on “How To Grow Milkweed from Seed

  1. I live in Detroit and yesterday found hundreds of milkweed seeds sheltering under a bush in a schoolyard. I’m assuming they were there in the winter time.
    So I think I should try starting them inside, we may get a frost tonight – our safe to plant date is either May 15/May 31.
    My apartment is very small. I’ll only have room for2-3 little pots but can I plant them outside after May 31?

    1. If those are seeds that survived outside through the winter, then they should be good to try and germinate—milkweed seeds need to be cold-treated otherwise.

      You can start the milkweed seeds indoors anytime now. A couple of weeks after the last frost date, you can either sow the seeds or transplant the seedlings outside. I hope this helps!

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