Starting Milkweed Seeds Inside for a
Longer Growing Season
Starting seeds indoors requires more patience if you’re letting things progress on nature’s terms…but there’s a quicker path to butterfly garden success.
But first, if you’re completely lost, you probably missed the first post from this seed starting trilogy. Once you’re up to speed, continue reading below:
- I tried using the milk jugs that I used for winter sowing last season. This didn’t work very well because the heated seedling mat couldn’t effectively warm the soil
- This season I’m using the small plastic cups again. Traditional 16 oz cups would also work
- I’ll still be using the performance enhancing trick listed below for faster germination
- After the seeds germinate, the seedlings will be placed under t5 grow lights
My current seed starting system includes old seed starting trays, clear tray covers, 5 oz. translucent cups, shelving for the trays, T5 grow lights, and a heated seedling mat.
As I write this, my heated seedling mat is keeping my Gomphocarpus fruticosus (swan plant), Calotropis gigantea (giant milkweed), and Asclepias curassavica (tropical milkweed) seeds a balmy 75-80° F while it’s below zero in the butterfly garden.
Why does this matter?
Since the seeds germinate at around 75° F, northern germination outside might not occur until late June or July. So your milkweed gets off to a super slow start and then, before you know it…your “runt of a plant” gets rudely interrupted by winter’s return.
I’d heard of heated seedling mats before, but foolishly discounted them as a “marketing ploy” in my early days of gardening. Once I broke down and bought one, I was simply amazed by the results. Not only did my seedlings sprout in record time, I also had my highest germination rate ever for tropical milkweed.
While spring sowing tropical seeds might be easier, what’s the point if these are the measly results:
This late-August tropical milkweed plant started from seed in a local butterfly garden. Even with the encouragement of soaking rains and sizzling summer sun, it never grew up to share nectar with a monarch, or feed hungry caterpillars.
For annual milkweed, starting seeds indoors can mean the difference between a long summer of beautiful blooms, or the joyless alternative above. I know what I’m choosing…
Note: While starting seeds indoors is a fantastic option for starting your annual milkweed supply, it’s much easier to continue that supply by taking yearly milkweed cuttings in fall or winter.
In my next post on starting seeds indoors, you’ll see photos of my entire setup and, whether or not seed starting indoors was successful.
Click Here for Milkweed Seed Starting Results (update by 2-28-2015)
Do you know other gardeners in USDA Zone 8 (and below) interested in growing annual milkweed plants for monarchs? Share this page and help a gardener out: