When to Plant Milkweed Seeds

You can plant milkweed seeds in the late fall or early spring, with fall planting being easier and best to do by the end of November. Planting in the spring requires cold stratification or heat shocking to prepare the seeds.

Planting Milkweed in the Fall

Collecting and planting milkweed seeds in the late fall is the best since it’s similar to how the plant self-seeds in nature. Plus, you don’t need to do cold stratification. Make sure to plant in late October or November before the soil freezes.

Prepare the soil by removing rocks and mulch. Proceed to water it. Plant your milkweed seeds and cover them with moist soil. Protect the seeds from critters by placing a chicken wire around the planting zone.

Planting Milkweed in Spring

when to plant milkweed seeds
When to plant milkweed seeds

If you decide on spring planting, the best time to do it is in the early spring, after the last frost. Planting this butterfly food source in the spring requires some preparations. There are two ways to go about this:

  1. Do the cold stratification of the seeds by putting them on a damp paper towel and placing them in the fridge for three to six weeks. This prepares the seeds for winter dormancy.
  2. Use the heat shocking method by soaking the seeds in hot water from 120 Fahrenheit (48.8 Celsius) to 130 Fahrenheit (54.4 Celsius) for 12 hours. Then, drain the seeds. Repeat the process three times, then wrap them in a plastic bag covered with a warm and moist paper towel for 24 hours. Keep in mind that this method is less reliable than the cold treatment, meaning the seeds are less likely to sprout without exposure to cold temperatures.

Once planted, milkweeds are low-maintenance. Water them daily to keep the soil moist for the first couple of days, and then do it if you notice the soil is dry.

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How to Germinate Milkweed Seeds

You can also germinate milkweed indoors and then grow and transplant them into your garden. In fact, germination rates are higher indoors, so you may benefit from this method, especially if you’re planting milkweed for the first time.

First, prepare small planting pots or peat pots. Then, fill the pots with a soil or seed-starting mix and water them. Scatter cold stratified milkweed seeds on the surface and cover them with an additional potting mix. Slightly dampen the additional layer.

Cover the pots with plastic bags to prevent your seeds from drying out. Milkweed seeds need abundant warmth and light, so keep the pots on a sunny window or under grow lights. Maintain the temperature at 75 Fahrenheit (23.8 Celsius) degrees. The germination process takes seven to 10 days.

Do I Need to Plant Milkweed Seeds Every Year?

Milkweed doesn’t require replanting each year. It’s a perennial plant, meaning it lasts for multiple years. If you want more milkweeds, simply harvest the seeds from the existing plants and plant them in other areas of your garden next year.

Where to Plant Milkweed

To ensure your milkweed grows well, plant it in an open area with a lot of space and full sun (at least 6 hours of direct sunlight exposure per day). Milkweeds thrive on either moist or dry soil; just make sure it’s tilled and well-draining soil.

Milkweed and the Monarch Butterfly

when to plant milkweed seeds
When to plant milkweed seeds

Milkweeds are the main host plants for Monarch butterfly eggs and several other butterfly and moth species. They’re especially important for Monarch caterpillars since this species only feeds on milkweed plant leaves.

Milkweed improves monarch butterfly habitat

Due to various environmental factors like host plant loss, habitat destruction, and climate change, the number of Monarch butterflies has significantly decreased in the last couple of decades. That’s why gardeners need to help by planting milkweed, improving butterfly habitat, and attracting Monarchs.

Native Milkweed to Your Area

Growing milkweed that is native to your area is essential for butterfly health. Planting non-native milkweed species attracts the ophryocystis elektroscirrha parasite that infects Monarch butterflies. Native milkweeds wilt during the winter, along with the OE parasite. New plants grow in the springtime, lessening the risk of OE infection.

Milkweeds that are native to the United States include antelope-horns milkweed, purple, white, and green milkweed, and California and Mexican milkweed. Additionally, you may find these native milkweeds around:

  • Common milkweed (Asclepias syriaca)
  • Butterflyweed (Asclepias tuberosa)
  • Swamp milkweed (Asclepias incarnata)
  • Showy milkweed (Asclepias speciosa)
  • Whorled milkweed (Asclepias fascicularis)
  • Desert milkweed (Asclepias erosa)

Keep in mind that many of these species of milkweeds have mutual native ranges, but some are native only to a few areas in the US. For instance, common milkweed is widespread, while desert milkweed is a native plant only in Arizona, California, Nevada, and Utah. California milkweed has only two native areas – Central and Southern California.

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