Why Harvest Milkweed Seeds?
There are many reasons to collect and grow seeds from your garden, especially milkweed seeds.
Maybe you have a milkweed plant that you or a neighbor really liked last season, and you want to continue growing it next year. Sometimes there is local variation within a plant variety, and this plant is especially well-adapted to your area, as evidenced by last year’s success. It is worthwhile trying to get seeds or starts from the area in which you will be growing it.
Get an Earlier Start
Nurseries plan for demand, and depending on where you live, they might not offer milkweed plants as early in the season as you would like. Sometimes you can get a head start on the butterfly season by using a sheltered area such as a porch or balcony, and growing your own milkweed will allow you to get set up earlier.
More Milkweed Varieties
Usually the more popular types of milkweed seedlings are offered by nurseries or online, but a much wider range of options is available when you start your own from seeds. Since the concentrations of cardenolides vary between species of milkweed, it is always good to have a range of options in your garden.
Avoid Pests from Nurseries
So, don’t let this one alarm you! As conscientious as nurseries are, there is always the chance of soil-born diseases coming into your garden, and commercial growers sometimes have outbreaks of mealybugs, etc. The more you can grow yourself, the better.
If your plants from last year have rewarded your efforts with large numbers of seeds, you now have a free source you can use yourself and share with friends.
Teach Kids about Plant Life Cycles
Starting seeds is fun and addictive – it’s a great way to get kids involved and let them learn about nature.
When to Collect the Pods
Here is a collection method that requires no special equipment and is quick and easy. Grab your safety glasses* and let’s get started!
Pods can be collected at various times throughout the year, either before or after winter. In the fall is best, as the pods will not have split open as much, allowing moisture to get in. The problem with moisture is that mold can form. When collecting in the fall, it is handy to get the pods before they actually pop open too much, releasing seeds attached to parachutes of fibrous floss (called coma). That can make a mess.
Secure Pods Before They Pop Open
If you have access to the pods while they are ripening, secure them with paper strips sometime in the summer before they pop open. Cut up strips of heavy brown paper (from paper bags or heavy craft paper) and secure the strips around the pods with masking tape. Some people use rubber bands for this, but those often break down in heat and sun. You know those old rubber bands you find in the back of the drawer that are sticky?
Collect seeds before pods look like this.
How to Tell When Pods are Mature
When you have taped up all the pods, keep an eye on them and look for when they start to turn brown. There are several things you can check on to make sure the seeds are mature:
- The seed pod has started to turn slightly yellow
- The seed pod has begun to split open or will split along a seam with a gentle squeeze
- The seeds inside have turned a relatively dark color, not white or cream colored
Never pick pods that are completely green. If a pod cracks open with a gentle squeeze and it’s slightly yellow, it’s ready!
Removing the Seeds
Go ahead and pick the pods and get them to a table with a clean bowl and a paper bag. Many people do this outdoors in case the floss starts floating around.
- Take a pod in your hands, holding the stem side in one hand and the end in another. Strip off the covering of the pod so that you have a cone-shaped arrangement of seeds attached to the floss.
- Holding the end of the pod that is mostly floss with one hand, pull the seeds off with the other, putting them in the bowl as you go.
- Place the seeds in a paper bag to continue drying and label it with the date collected and type of seeds.
Don’t forget to wash your hands before taking off your glasses, and you’re done! Time to start preparing for the next season!
Before Planting Your Seeds
Unless your seeds are tropical milkweed (Asclepias curassavica) place them between layers of damp paper towels in plastic bags or closed containers in the refrigerator for 30 days before planting.
This simulates the cold and moisture that they would experience in nature to help break down the outer layer of the seed casings to allow germination. This process is called cold stratification. Many species of milkweed require cold stratification, but tropical milkweed seeds do not.
Thanks to Darlene Loo-McDowell of Sharing the Butterfly Experience and Connie Hodsdon of Flutterby Gardens for providing information used in this post!
Milkweed Sap Warning
*Milkweed sap is an eye and skin irritant. Many people get sap on their hands and then rub their eyes. Milkweed sap in the eyes is a medical emergency, and who has time for a trip to the emergency room? Tip: If you don’t want to wear gloves, at least wear safety glasses. It would be difficult to rub your eyes with glasses in the way, so the safety glasses being on your face will be a reminder that you still need to wash your hands.