No, you do not want to put them in the freezer. Doing so would decrease germination rates. In nature, the seeds will experience periods of freezing, but the conditions would be very different than those in your freezer. To cold stratify your seeds, put them in a damp (not wet), sterile medium (course silica sand or vermiculite works well but many different mediums can be used), seal them along with a little extra air in plastic bags, and place in your vegetable crisper or an area of the refrigerator where they will not freeze.

Winter sow them! Works great.

I agree. Wintersow!

Here is a link that might be useful: Wintersowing FAQ

Winter sowing may be easier in a lot of cases, but isn't always the best choice. One example is if you want seeds to germinate at a specific time (early, to get a jump start on spring, or, late, for crop timing). There are also other potential complications to winter sowing, like predation (those darn squirrels) and storms (wind blowing your containers around). If only a few seeds are available, careful and precise indoor cultivation may lead to higher germination rates. I'm in no way saying not to winter sow, I'm just pointing out that there are lots of valid reasons to want to know about stratification techniques.

I love winter sowing, but if you're in a warm zone, your seeds may germinate better if you stratify them in the fridge. I'm in 7b, and I've found that columbines have a higher germination rate if I put them in the fridge than if I winter-sow. (But I do gt pretty good germination with winter sowing---I only use the fridge if I have a very few 'special' seeds.)

I do what Brandon7 does. in fact, right now, I have dogwood,and southern magnolia in my crisper drawer right now. I've done these before, and just seed them when it's close to frost free. I will seed some directly then, and for backup, some in pots. I don't want to water a bunch of plants all summer and then have to overwinter them. I may end up doing that for the magnolia tho.

Perhaps I'm simply fortunate to live in a zone where winter sowing is ideal but so far I've successfully grown apple trees, pear trees, ornamental dogwood trees + shrubs and a long list of perennials via winter sowing. The trees are as tall as I am after only 3 years. Winter sown shrubs & perennials all bloomed this year.

In nature, I'm sure they would be subject to freezes?

You don't identify your location so it's somewhat challenging to offer advice for cold stratification. The Clothier's database is reliable for most purposes and may be helpful to you. Knowing the botanical names will help you navigate the website.

As the above posters have advised you, the refrigerator isn't the best alternative to what's outside your door so long as the external temperature allows a sufficient cold spell to break a seed's germination needs.

FYI - winter sowing provides the closest approximation to a natural pre-chill/stratification plus it protects the seeds from wind, rain & predators, allowing the seeds an environment in which they have a significantly higher chance of germinating than they might otherwise enjoy.

Best of luck to you!!

Here is a link that might be useful: Tom Clothier database

"winter sowing provides the closest approximation to a natural pre-chill/stratification..."

...which might not be what you want since, in nature, germination rates are often relatively low AND there are the "special cases" mentioned earlier.

"...it protects the seeds from wind, rain & predators"

I'm not sure that came out right (maybe it did?). Winter sown seedlings are infinitely more exposed to such things. The winter sowing forum is full of instances where people's containers got blown away or squirrels got hungry and looted the stash. I've never had much wind or a squirrel in my refrigerator.

But, as before, winter sowing can be fun and rewarding. It's just not always the best solution for every case.