Milkweed seeds can be started in the winter and basically left alone until they’re almost ready to transplant.
For us, late January or February planting should give plenty of time for cold stratification.
You will need containers. Gallon milk jugs or distilled water jugs work great, but you can also use 2 liter soda bottles or even large box lettuce containers. Make sure you have thoroughly rinsed them clean and label them with a permanent marker.
- Poke or drill holes in the bottom for drainage—about 4 to 8 quarter inch holes. If you’re using fruit or vegetable boxes, poke holes the top also.
- Draw a line around the container about 4” up front the bottom.
- Cut along this line on 3 sides leaving one side for a hinge. Don’t use the handle side for the hinge side. Keep it straight because you’re going to tape it closed.
- Add about 4 inches of potting soil that has been well wetted. Do not use soil with moisture beads because it sometimes causes poor germination or stays too wet for this method.
- Plant your seeds by placing them individually or sprinkle them. Press them down lightly, then cover with about ¼” of soil.
- Close your container and seal the seam securely with duct tape.
- Leave the caps off (so that rain or snow naturally waters them) and set them outside where they get a few hours of sun each day. If they are in an area where the wind could blow them over or animals disturb them, stake them down or put rocks or bricks around the bottom of the container.
- Just let them rest till spring. Then make sure there is some condensation in the jug. If not, dig them down into the soil and water the soil around it so that water seeps up from the drainage holes.
- Once you have seedlings, you may need to move the container to a better spot until it’s time to transplant to their final location.