Butterfly Milkweed Seed place 1/8 inch below the soil surface using a deep pot, since most milkweeds have a long roots. They tend to grow at 70 degrees Fahrenheit within 14 days. The seedlings should be kept moist for the first three weeks after they sprout, and then transplanted to larger containers with quality soil if necessary. Fertilize them lightly after the seedling stage, using a regular flower fertilizer. Cutting off the top of the plant after they are 8-12" creates more stalks and more leaves. It takes about 2 months before the plant is large enough for caterpillars to eat.
After the leaves have been eaten, cut the plant off about three inches above the soil or just above the lowest branching of the stalk and the plant will grow back fuller and create even more food for Monarchs. It takes 60 days from seeds to have a plant large enough to support a caterpillars' food needs. Aim to create a refuge of lush milkweed for the migrating Monarch and have extra plants in case of any shortages. Once you have a good supply of milkweed, you can purchase eggs, small caterpillars or chrysalis to ensure there are butterflies in your area immediately or assist with the genetic diversity in remote areas about when to plant seeds or when to buy plants or transplant them safely outdoors.