Milkweed Planting Instructions

Narrowleaf Milkweed – Asclepias Fascicularis (California’s Native Host Plant for Monarchs)

The first step to helping save the Monarchs (and one you can do right in your backyard) is to plant milkweed. Monarch caterpillars ONLY eat milkweed and Monarch butterflies will look for milkweed so they can lay their eggs on this host plant. Could that be in your backyard? We hope so!
Here is what you need to know:

Stratify Your Seeds!

For best results, we recommend “stratifying” your seeds. Stratification simply means tricking your seeds into thinking they’ve survived a cold winter and that it’s now spring. This does take a little planning so be sure to do this ideally one month before you’d like to plant.

How to Stratify

Most Milkweed varieties need 30 days of cold exposure to break their dormancy cycle and this can easily be done in your own home. Here’s how…

Materials Needed

  • 1 Quart Ziploc  Bag
  • Milkweed Seeds
  • Paper Towels
  • Sharpie Pen

Step 1: Wet a paper towel and lay on a flat surface. 

Wet a paper towel and gently wring it out so it is damp but not dripping with water. Too much water may cause the seeds to mold inside the bag.

Step 2: Sprinkle your seeds on the paper towel. 

It’s best to sprinkle the seeds onto half of the paper towel so when you fold it, the seeds will not overlap. Spread them out so they’re not touching each other.

Step 3: Fold the paper towel into quarters. 

​Step 4: Place the paper towel into the bag, seal, and label. 

Label the bag with the date and type of seed and the date you put them in the fridge. You may even want to set a reminder on your phone or calendar so you can remember to take them out in 30 days.

Step 5: Place in the refrigerator for 30-60 days. 

​Store the mixture in the refrigerator (33–38°F) for the recommended time on your seed packet. For Butterfly Milkweed (Asclepias tuberosa) Prairie Moon Nursery recommends 30 days of cold stratification.

Make sure to put your seeds somewhere safe in the fridge where they will not be disturbed. I like to put the bag into a tupperware container to ensure they don’t get smashed or damaged.

Planting Seeds

1.
Peat Pot Seed Starters

2.
Seed Starter Trays

3.
Seedling Mix

Using an egg carton works great to start your seeds. We’ve had good luck with these mini green houses you’ll find at your local nursery. We also have had the best results using a “seedling starter soil”.

Step 1: Place seeds in trays

​After 30-60 days, it’s time to plant your Milkweed seeds. You can plant them in seed trays, peat pots, small pots or any other container that allows for water drainage. Dampen your soil with a spray bottle full of water and place 1-2 seeds into each 2″ container. Sow seeds lightly on the top of the soil. You may press in gently but they need light to germinate so please don’t bury them!

Step 2: Water seeds gently

Be gentle when watering new seedlings because they are very delicate. It is recommended to water from the bottom up by adding a half-inch of water to the bottom of a tray and placing the pots inside this tray. Some people prefer to use a spray mister to water their seedlings.

You can check the soil moisture simply by touching it to see if it feels damp. Take care not to overwater your seeds which can lead to fungus growth. It is helpful to have a fan nearby to provide airflow and ventilation.

Step 3: Your seeds need light!

Make sure your milkweed has enough light to grow whether that be under an artificial grow light or near a sunny window. If your seedlings start to become “leggy” expose them to more light.  The sturdier the seedling, the better!

Step 4: Plant outdoors

Milkweed seeds can be sown outdoors after the danger of frost has passed and the seedlings have grown around 1-5 inches high. To make the transition from indoors to outdoors less stressful, start by putting the seedlings outdoors for a few hours a day for up to a week before planting them outdoors. ​

Resources

Save Our Monarchs
The American Meadows Blog: How to Germinate and Grow Milkweed Seed.
https://www.americanmeadows.com/blog/2015/06/11/how-to-germinate-and-grow-milkweed-seed/Prairie Moon Nursery: How to Germinate Native Seeds.
Prairie Moon Nursery
https://www.prairiemoon.com/blog/how-to-germinate-native-seeds
​
Henrikson, Bob. Gardening with Prairie Plants. Nebraska Statewide Arboretum.
https://plantnebraska.org/plants/bloom-box/resources-for-bloom-box-gardeners.html

Printable PDF Instructions

More information from our friends at the Pollinator Posse
Narrowleaf Milkweed – Asclepias fascicularis

Milkweed is the host plant for the Monarch butterfly which means it is the only plant the caterpillars can eat.  The adult butterfly lays her eggs on the milkweed and the caterpillar eats the leaves for about 2-4 weeks until it is ready to pupate and become a chrysalis.  Before making a chrysalis, the caterpillar usually crawls away from the plant to find a safe spot on a branch or structure to hang and develop.  The adult butterfly emerges from the chrysalis after about 10-14 days.  Since insects are cold blooded, all these stages are influenced by temperature – and take longer at lower temperatures.  Narrowleaf milkweed is native to California and healthier for caterpillars than the non-native varieties.  Like all native milkweeds, it goes dormant in the winter, seeming to disappear, but returns in the spring.

 

You can scatter these seeds in your garden during the fall, winter or early spring and let winter rains water the seedlings.  It also works well to plant them in pots or 6 packs to get them started, and then transplant out in the garden in the spring or early summer.  Milkweeds are deep rooted so need a lot of depth if planted in pots. Pollinator Posse

For more detailed explanation and advice on best practices, please visit the Monarch Watch website

Monarch Watch