Planting and Care of Milkweed Plants

As reported in The Monarch Newsletter, an experiment was conducted to determine the effects of transplanting, fertilizing, and light on milkweed plants.

Milkweed seeds were planted in 4-inch pots, 4-5 seeds per pot, in early Spring. By the end of May, the plants were about 6 inches high. The following tests were conducted:

• Transferring to 1-gallon containers vs. keeping in 4-inch pots
• Fertilizing every week, every other week, or water only
• Plants were kept either:
  • In containers, in maximum sun or partial shade on a patio, or indoors
  • In the ground in a sunny location

After one month, the following observations were made:

• Transplanting into 1-gallon containers and fertilizing resulted in taller, bushier plants with bigger leaves.
• Fertilized plants were greener than non-fertilized plants, though weekly fertilizing was not much different from fertilizing every other week for the container plants.
• There was not much difference whether 1 or 2 of the 4-inch pots were transferred into a 1-gallon container.
• Plants in full sun grew faster than plants in partial shade.
• Plants left in small pots benefitted from weekly fertilizing.
• Indoor plants were bigger as a result of fertilizing, but the plants were softer, thinner, and had very green leaves compared to the outdoor plants, which were tougher. The indoor plants were infested with yellow aphids and a few whiteflies. The outdoor plants were virtually free of pests.
• Plants in the ground were healthy, but varied considerably in size.

Milkweed is crucial to the Monarch Butterfly. Here are some sources to get you started with adding this beautiful plant to your butterfly-friendly garden: