Hi! I'm hoping someone can give advice on starting some native and non-native species' seeds that call for stratification prior to their germination.
Specifically, I'm trying to start Penstemon and Agastache (Anise Hyssop) and Perennial Snapdragon (Antirrhinum majus) to add to my 'mostly deer resistant' sunny/part shade garden in Zone 7b.
I once tried to germinate Anise Hyssop using a winter-sowing method outdoors in a South-facing protected location, in one-gallon milk containers, without success. Now I hope to try to get seeds started inside, and under grow lights.
Any tips for success would be appreciated! Thanks!

I start seeds on a damp paper towel in sandwich box type plastic containers (I think lunch meat comes in them) - they're cheap and stackable (don't forget to label and date). I spritz the paper towel with fungicide to keep it from molding. Check periodically to see if anything is germinating. If little roots grow into the paper towel, cut out the paper towel and plant it too. I've started quite a few west coast natives this way.

Thank you, Lucy. What type of fungicide spray did you use? I was reading in the Daylily forum that hydrogen peroxide was added to the water used to moisten the paper towel. I hadn't heard of that method before…. but am open to suggestions of what has worked for others.

I've never used hydrogen peroxide as a seed fungicide. I just use copper sulfate spray.

I use Park's Bio-Domes for my seed starting and I always get just about 100% germination, I love them. I have them set up under a 4' LED grow light for 6-8 weeks, takes up my kitchen table, but it's definitely worth all I save vs buying plants.

I start impatiens for my very shaded front porch and then a lot for hummingbirds every year... several types of salvias and agastaches, cardinal climbers, moonflowers, spanish flag. I've also started marigolds, morning glories, snapdragon vines, million bells, coneflowers, all with equally excellent results.

I always store my seeds in my fridge, so if any need cold prior to planting, that takes care of it. Seeds also last a lot longer in the fridge, I plant seeds that are up to 5 years old without any problems. They probably last longer, but I use them up before that point.

One of the most important things though is to gradually acclimate them to the outdoor sun, wind and temps. Start with a few hours outdoors in morning sun and gradually increase it until they can stay out all day and night. One year I got very lucky and it was warm but overcast for a week. I think I put them in the garage for one night and then just left them out after that. But that's rare, plan on up to a week to acclimate them before planting them in their final spot. They can burn up easily in the sun and will die if you don't.

Murky said: I use Park's Bio-Domes

Will they fit in the refrigerator? How do you stratify?

Nearly all agastache species germinate without pretreatment at room temperature. Most want to be exposed to light so only just cover the seed. (They don't need to be completely exposed.) This includes Agastache foeniculum, if that is the Anise hyssop you are thinking of.

For penstemons, it depends on the species. About 75% germinate at room temp without pretreatment, the rest requiring a cold period prior.

Antirrhinum majus germinates at room temp without pretreatment.

The seeds only are stored in the fridge before planting, not the entire Bio-Domes.

Murky said: The seeds only are stored in the fridge before planting, not the entire Bio-Domes.

I'm with Lucy in confusion — I thought cold stratification requires
moisture.

I always thought just cold. Maybe I've just been incredibly lucky with seeds then?

My motto: whatever works 🙃

Murky said: I always thought just cold. Maybe I've just been incredibly lucky with seeds then?

Or the seeds didn't need stratification - stratification does take cold and damp.

Yes, if seed was placed in the fridge dry, they aren't cold stratified. They are just cold. In uncommon cases, though, even this can help some, but it's not the same thing.

Thank you, everyone, for your responses and ideas!
These seeds have been chilling for 5 days in the frig (unopened, dry in a sandwich bag).
On those seeds that don't require stratification, I use a dome over the seeding tray until they're up, then slowly acclimate them to a less humid environment. And I use grow lights. No unusual challenges with 'regular' seeds, just not sure about the best way to proceed with those that specify a stratification to increase the chances of germinating. And on the Anise Hyssop and Penstemon seed pkgs - that are natives - the instructions say to stratify.

Unopened, dry in a sandwich bag is a good way to store seeds to maintain freshness. Stratification requires a cool (usually 35*F and 45*F - just like the refrigerator), damp, extended period of time (3 - 4 months) to simulate winter and break dormancy. Seeds that don't germinate immediately go into dormancy to wait for a more opportune germinating time. Most temperate plant seeds need winter to break dormancy, either the real deal or a pretend in the refrigerator one.

Hi Jan, @ love2garden2

Alplains lists 4 species of native Agastache seeds. He indicates all are his code (1) "No cold stratification necessary: germination is usually complete within a month or less."

He offers a long, enticing list of Penstemon species. Maybe yours will be on it. Germination varies by species. Many call for cold stratification for various times and he gives a specific range for each such as 3:8 which means code 3 below, stratify 8 weeks:

"(3) Cold stratification required for the number of weeks indicated, followed by exposure to warmth, after which germination is usually complete within a month or less.
(4) Cold stratification required for the number of weeks indicated, followed by exposure to warmth, after which germination may be staggered over several weeks. Another period of cold may be helpful to encourage remaining seeds to sprout. Alternatively, seed may be exposed to outdoor winter conditions for germination in the spring."
http://www.alplains.com/

His prices seem cheap to me considering the rarity and specified provenance of most of his offerings.

Rick, @Leftwood
You are correct. Cold stratification always implies cold, *moist* stratification, whether indoors or out.

The recommended temperature is generally about 40°F (4°-5°C).

Don't freeze moist seeds without solid information from a reliable source. It can be fatal. It can also be fatal to some dried seeds. For ones that tolerate it, freezing dry can prolong longevity.

There are lots of ways to provide the cold, moist environment. Standard white paper towels have been bleached. As such, they tend to resist the growth of molds for a month or so. Have them damp, not soaking, unless there is a large volume of dry seeds to absorb the water. The seeds need air too, so don't press all the air out if you're keeping them in a sealed plastic bag.

My preferred stratification medium is milled sphagnum moss. It can hold a lot of both air and water without being soaking wet. And it's naturally resistant to molds. It only takes a small amount. I use about a tablespoon dry (then pre-moistened) for 10-20 daylily seeds in a little plastic bag. These days I have to order it from the source:
https://www.mosserlee.com/prod...
I've used it for decades, especially for very tiny seeds prone to damping off. It's medium brown when wet and gradually pales to beige as it dries. It makes it easy to see when watering is needed. If I think I've overwatered them, I dust a little dry sphagnum on the surface soak it up. It's a very finely milled moss. It seems a bit pricey, but used in its best ways I consider it priceless. I trust it for expensive hybrid petunias seeds, ageratum, begonias and in general any kind of tiny seedling that needs a slow pampered toddlerhood.

Pat

Thank you, Pat! I appreciate your advice, sharing the techniques you've used, and resources.
I will contact Alplains - I am impressed with the seed genera and varieties they offer, as well as their detailed instructions. I now understand why I had what seems like many failures in the past! It makes sense to try and mimic what Mother Nature does.
What a great resource! A new seed starting adventure awaits. So many natives and perennials.
Thank you to everyone who has shared their thoughts, experiences, and ideas on this subject. I will likely try several different methods, to see how they differ, since this is my first attempt at indoor stratification.

You guys are great!!

Lucy68 said:Seeds of temperate plants need winter, either the real deal or a pretend in the refrigerator one.

Surely this was a typo. There are myriads of examples that prove it false.

Leftwood said: Surely this was a typo. There are myriads of examples that prove it false.

Yes, a typo. I have the flu and am not thinking very well. Thank you for pointing it out. I'll fix it.

Hi I cold stratify my seeds in small clear containers with lids. I use wet paper towels, spagnum moss, or vermiculite to stratify my seeds. Life gets in the way and I don't always have the time for the full course of cold treatment. I cheat and put them in the freezer for a day or two and then l put them in the fridge for a couple of days and repeat the process a couple of times. This makes the seed think it has gone through a couple of freeze thaw cycles. I then take it into room temperature. They germinate and get put into small cups. This has worked well for me over the years.