We recommend planting milkweed seed in the spring or fall in most parts of the U.S. In the fall, the cold will start the stratification process of the seeds ie. exposing them to the cold temperatures that they would experience in the wild and that trigger spring germination. You can also plant in spring. If storing your seeds until then, we suggest storing them in the fridge but not the freezer! When you are ready to plant, it is like planting any other wildflower seed. Clear the area, sow your seeds on the top of the soil and lightly compress for a good seed to soil contact. The biggest mistake folks make when sowing milkweed is planting them too deep. The rule of thumb is that it should be no deeper than it is thick. It doesn’t have the energy to push through all that soil and needs sunlight to germinate.
Most milkweed species prefer lighter, dryer soils to heavy, clay ones. If you have clay soil, you can loosen it with gypsum or by adding some good loose loam. Do not cover them with anything including mulch. If for some reason, you feel you must cover them, then do so with a light layer of straw.
Once Planted, Add Water to Milkweed Seeds
Keep your newly sown seeds moist until germination occurs and until they are 6-8 inches tall. Many milkweed species are drought-tolerant once they’re established. You can time your seeding to take advantage of your local rain patterns. Milkweed will not establish well if you don’t water – rain or by hosing the area yourself!
Collecting Milkweed Seeds
Regardless of species you should collect seeds in the fall, when the seed pods have opened but before they begin to crack. There is an exception to this as seeds of common milkweed, should be collected as soon as the pods turn brown. Remove them from the pod and separate them from the silky floss right away. You can store common milkweed and swamp milkweed for about 2-3 years, all others you should plant no later than the following spring and ideally in the fall right after you collect them!
Easy Tip on Milkweed Seeds
Keep an eye on where they are establishing if you already have some. What is the soil like and try to duplicate that! Remember to think of the natural cycle – what happens in nature is what you should duplicate and you’ll have success and the Monarchs and other butterflies will thank you!