Sowing perennial seeds and more importantly, being successful with them, is a subject full of myth and lore.
Let’s Start With By Dispelling A Major Myth
Do Not Freeze Your Seeds
To begin with, before sowing perennial flower seeds, do not freeze them if they’re in envelopes or packages.
Dry seed does not freeze well at all. There is a safety mechanism built into perennial seeds that allows them to be frozen if damp (as in outdoors) but not if dry ( as in a seed pack).
Dry freezing does bad things to many seeds.
Your seeds are fine if kept dry and at room temperatures or in the crisper of the refrigerator. I store most of mine in shoe boxes stacked up in a cupboard in our cool basement.
The Single Most Important Thing To Know
Is that you’re going to mimic nature.
Seeds germinate because of hormonal changes inside the seed. Our job is to mimic the conditions the seed wants.
If you understand this, you’re well on the way to success.
Two Important Temperatures
We need to be able to provide two important temperatures to the soil for our perennial seeds to germinate.
- The first is 40F. And you can get that in the crisper of the refrigerator.
- The second is 70F and you require a heat mat for this.
Room temperatures are generally too cool (soil temps are 10F less than room temperatures) for good germination.
One Important Number
The number is 90. Ninety days in fact.
Perennial Seed Success
Here’s the important thing to know. The majority of perennial seed germinates using one of two options.
- Some perennial seed wants to be cool at 40F for 90 days and then warm at 70F for 90 days in order to germinate.
- Some perennial seed wants to be warm at 70F for 90 days and then cool at 40F for 90 days in order to germinate.
The vast majority of perennial seeds will germinate using the first technique. 90 days at 40F and then move to warmer temperatures of 70F and watch them germinate within 90 days.
How To Do This
You can sow your seed in pots and put them in the fridge crisper or the beer fridge.
Or, you can put the seed in a baggie with a barely-damp hand-full of vermiculite or soilless mix and then put it in the fridge.
After 90 days, remove the pot/seed (you now sow the seed into a pot if in a baggie) and give the seeded pot warm temperatures of 70F soil temperature.
The seed will (usually if alive) now germinate.
Containers For Starting Perennial Seeds
Containers can be anything that will hold adequate amounts of soil (like a four-inch pot) and not dry out too much between waterings.
Four-inch pots are ideal in my experience.
I do not recommend using the Internet-recommended things such as egg carton or…
When To Put Into Individual Pots
When the seedlings get to the 4 leaf stage (4 true leaves not seedling leaves) then transplant to their own individual pots and grow until they are large enough to go into the garden.
First Year — Don’t Plant Outdoors Until After Frost
The headline says it all. Frost will kill tender seedling plants that have been cossetted indoors. Plant after frost for best results.
Harden them off as you would an annual seed before going outdoors.
Once they’ve been outside at night for a few nights, they’ll be fine with most cold temperatures.
Note I’ve written an ebook on Amazon “Free Plants” about propagating your own plants on a backyard scale.