Stratification and Winter Sowing: Tools for Your Toolbox

Yesterday, I spent a long time filling seed flats and pressing seeds into dirt - and then I took them outside and set them to germinate. The temps were hovering right around freezing, and there was light snow coming down - the perfect conditions for growing things. Or at least, for winter sowing

(Note, there was originally a link and short quote from a website about the subject, but the owner of the site apparently took offense because I attempted to drive traffic to her, so I strongly recommend you avoid her site, to avoid offending her. I will go out of my way never to mention it or any of her work again. ;-))

The plants I was planting were stratified - that is, they require or tolerate a period of cold before germination. Some plants won't germinate at all without a cold period, others will take as long as years. Others will germinate just as well. How do you know which plants will do well with winter sowing?

Anything that tells you in its germination requirements that it needs stratification or a period of cold. And anything that says "self sows" - these are all plants who seeds will tolerate or even require cold periods, gradually warming to grow. Plants native to temperate climates - anything that indicates this in its name, for example. This includes an awful lot of cold-hardy perennials, and a surprising number of garden annuals as well. Most temperate climate plants form seed in summer or autumn, and the plants have a much better chance of surviving in most cases if they don't germinate right before winter - so a natural period of embryonic dormancy makes perfect sense for plants. Mimicking those conditions improves germination rates of many seeds, and it allows us to plant at earlier periods, less busy ones, than we might otherwise.

Now the conventional advice for stratification is to put the plants into the fridge - but I don't have a conventional fridge, so that's not a good choice for me. Moreover, even if I did have one, I grow a lot of plants, and would begrudge the space taken up by an awful lot of jars of seeds. And nature does a terrific job in my climate of providing adequately cold temperatures.

I do some of my seeds in trays and pans like shown in at the Wintersown site linked above, but I also start some of my plants in the fall, in nursery beds. These are garden beds that I'm done using for the year, that have good soil and a protected location - I plant elderberry, apple, quince, peach and pear seeds here, as well as juniper, black cap and cranberry bush viburnum. The plants will spend the season in this bed, or be dug out and potted up, before a final plant out.

Some plants that you wouldn't think required stratification do considerably better with it - for example, parsley seeds, which take forever to germinate under traditional greenhouse/indoor conditions germinate very rapidly after a week of cold treatment. Tomatoes actually respond to cold treatment pretty well, although they produce later than early tomatoes will. In my climate, only cherries produce really well when grown this way, but it is an excellent way to get late tomatoes - say, if you don't want to be standing over a canning kettle in August or if you are planting tomatoes for pots to be brought in for overwintering.

Most experienced gardeners know a little about stratification, but I think few of us have fully plumbed its possibilities - for improving germination, extending our garden season and also balancing the workload which goes with the garden.

It is too late for many southern gardeners to winter sow without recourse to the fridge, but for those of us in northern places aching to get some seeds in the dirt, now is the time!


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"It is too late for many southern gardeners to winter sow without recourse to the fridge, but for those of us in northern places aching to get some seeds in the dirt, now is the time!"

Well, our "dirt" is buried under two feet of snow!

I've had a bit of experience germinating seeds that need two stratification periods. Examples include most native viburnums. In nature, they would germinate the second spring after falling to the ground. If you do it right, using the fridge, you can get them to come up the first spring. But sometimes it's just easier to plant them outside in pots and wait 'till the second growing season.

Yeah, winter sowing! It's a great method for starting LOTS of stuff when you don't have much space inside - I do my tomatoes, basil, peppers and stevia inside but everything else gets sown and then thrown outside to do its own thing.

This forum on Gardenweb is dedicated to winter sowing and there are lots of good discussions and answers to any question you can think of:

My prairie and savanna seeds are nestled in closed containers full of damp potting mix in the enclosed area under my front porch. I'll be taking them out to germinate sometime in late March. Apparently natural cold-temperature variations work better to ensure germination than constant-temp. refrigeration, at least so I'm told.

I also sow many native plant seeds in fall, "lazy" gardener that I am. Just love watching those little babies come up in early spring. Some perennials can be planted in August: they germinate and grow before the first frost and then bloom the following year. I did that with some horsement (Monarda lambada) last August

You don't have a conventional fridge? Please elaborate!


By Daniel N Smith Jr (not verified) on 18 Feb 2010 #permalink

I have a flat of seeds sitting in a cold frame (a bottomless box covered, for stratification purposes, with window screening so the rain and snow can fall onto the flat). The flat has been there since mid-December because some of the things I'm stratifying require 90 days - particularly some of the echinaceas - and winter is over here by mid-March. Putting window screen on top of the cold frame openings keeps rodents and birds from eating the seeds. The frame sits on an asphalt pad so I don't need to be concerned with critters digging their way in. In a week or so I'll be putting the windows on top of the cold frame openings and putting flats of vegetable seeds into the frame - the warmth will then start the stratifying seeds germinating.

I think it's important to note that the seeds that need stratifying are often fussier than, for instance, easy-germinating veggie seeds like lettuce. If your first (second, third ...) attempts don't work, it may be that the seeds were very dormant or weren't viable. Some seeds need alternating warm-cold-warm periods to germinate, some need two years; some need light, some not. Look at your technique, fix any problems, and keep trying if these are plants you want to grow ... it's very rewarding to grow them from seeds to blooming plants! You might see if your local Extension service or a nearby botanical garden have info on seed germination. Prairie Moon Nursery ( has a great catalog and cultural guide for those of us trying to start seeds from prairie, savanna, and forest habitats.

I also put a small plastic container, holding about a pint of seed-starting mix, in a plastic bag into the fridge with one of the echinacea varieties seeded on it, because I didn't get those seeds until a month ago and they need 90 days to stratify. I'll take it out of the fridge at the end of April and put it outside so the seeds germinate. Last year I got almost 100% germination of Echinacea purpurea (purple coneflower) seeds that were stratified in the fridge this way. If you only have a few kinds of plants to start, this works well and will take up only a little space. Remember to punch drainage holes into the bottom of the plastic container - you can reuse one that you would have otherwise recycled.

Have the guts not to lie Sharon, you copy and pasted copyrighted material without permission. You got your nose out of joint because when you got caught. Your lack of professionalism is clear in your edit.

TG Davidoff

Whoa, Trudi, hold your horses for a second. How much text did Sharon copy? Somehow I doubt she copied more than a few sentences or maybe a paragraph or two, easily covered under "fair use". And if she linked to the actual author (you?), then what in the world did she do wrong?

Please tell me the objection isn't over Sharon linking to text posted on the Internet. Because, um, if you post on the Internet, it's kind of public already. If you don't want anyone else to read it, then write in a paper journal and hide it under your bed.

Sharon's brief quotations from, endorsements of, and direct links to other helpful sites are a great benefit to us all. I am extremely disappointed in the content and spirit of Ms. Davidoff's post.

As per my commenting policy, even raving lunatics who fail to grasp the concept of fair use are permitted to comment here. 1 paragraph from an article, with the address of the site doesn't represent theft in any sense whatsoever. And I will say it is still a very good site, even though the owner is a complete nutjob.


No hotlink to the source, didn't name the author and more than a parapragh, taken without permission and pasted onto a commercial website. I have a google cache of the page.

From the Fair Use page at US Copyright these lines might be helpful...

"The distinction between fair use and infringement may be unclear and not easily defined. There is no specific number of words, lines, or notes that may safely be taken without permission.

Acknowledging the source of the copyrighted material does not substitute for obtaining permission."

There's a lot to be said for asking first.

There was a link - a broken link, but completely visible and intelligible to anyone who wanted to paste it in. Had you contacted me with polite concerns that the link was broken, rather than accusation of theft, I'd have fixed it and included anything you wanted. But since you'd rather call names, I don't see any reason to pay attention to you. As for fair use, you'd have a really rough time making your case - because of the size of the quote in relation to the article, the benefit to the public (non-fiction has greater leeway than fiction), the attribution visibly included, the fact that it didn't cost you anything, but in fact sent traffic to your site, etc..

It is not necessary to ask permission to review a public website, as you know - otherwise, there would be no negative reviews, ever.

Obviously, you've got a lot of free time on your hands, and are enjoying this. That's fine, but I've got better things to do than respond to drama queens.


I am so sorry you were attacked in this way. Your article is a very good one and I was going to ask if I could use it on my site.

As for Ms. Davidoff, she once attacked me in a very similar manner and still tells all who asks to avoid my site because I am a "thief" (I only requested input for a database that was being added to another garden site).

Just didn't want you to feel as bad as I did when this happened. Great article!!!