Long story short...most native seeds need winter to unlock.
Most native seeds need "cold, moist stratification". That just means winter...OR a winter-like experience.
Imagine seeds that are ready in the fall, falling to the ground and growing seedlings right away...only to be killed by winter. Our native plants have evolved to work with nature. They fall and, for the most part, need winter to "unlock" their ability to germinate. Brilliant!
See below for some of the most popular ways to give your seeds "cold moist stratification".
#1 Do as nature does
You can sow your native needs in the fall to give them the winter they need, naturally. Just pay attention to the sowing depth. If you aren't worried about sowing depth you can literally just sow on top of snow.
PROS: Easy as can be. No transplanting needed.
CONS: Less germination (usually). Hard to see what is your native seedling and what is a weed. You need to have a decently prepared sowing area for this. Seeds may move with the snow or rain.
#2 Contain it
Sow your seeds in a pot or in a seedling tray. Leave outside in a semi-protected area over the winter. (think, out of the sun, under a bench BUT NOT in a warm shed). Add hardwire mesh over the pots or the trays to keep critters from snacking on the seed. You can hold down the mesh with a brick or wood, but don't block the soil from receiving snow.
PROS: Easy. Better germination and control than #1.
CONS: A little more work than #1. Need to transplant. You have to protect from critters.
#3 Milk jug winter sowing
Milk jugs can act as a winter barrier from critters, and also act as a mini greenhouse come late winter/early spring for a jump start on growth. Cut the bottom half off your milk jug...almost...leave an inch or two to act as a hinge. Poke several holes in the bottom of the jug for drainage. Add 2-3 inches of soil and then water the soil. Sow your seeds as usual. Put the top half of the jug back in place and duct tape all the way around the cut. Remove the cap, you don't need it. Place these in the shade outside over the winter.
PROS: Good control. Good germination. No wire mesh needed. A lot of information online about this.
CONS: Preparation of milk jugs. Need to transplant.
#4 Winter in your fridge
You can give your seeds the cold and moisture they need to be able to germinate...in your fridge.
Put your seeds in a plastic ziplock baggie with a handful of damp (NOT wet) vermiculite or clean sand. Label well. Put in the fridge, not the freezer. Sow in the spring.
PROS: Good control. You can sow in the spring.
CONS: More work. Taking up room in your fridge.
Let's talk ferns...and forget everything you've read above...
Ferns have their own fascinating way of reproducing, and are relatively unchanged for hundreds of thousands of years. Here's one method to get them started, from American Fern Society.
"Nine Easy (if you are patient) Steps for Growing Ferns:
1) You will need a clear plastic container like the ones supermarkets use for cakes or cupcakes. This will ensure high humidity.
2) The potting soil must be good quality not a generic brand. This very important.
3) After putting the soil in the container dampen it. It should feel like the humus soil you would feel in an oak forest. Not too damp not too dry. To kill bacteria and fungal spores place the container in a microwave oven and heat for 3-5 minutes (until it is steaming pretty good). Be careful, too long and the container will begin to melt. Then let the soil cool for about an hour.
4) Sprinkle the spores on top of the soil , just enough so that you can see some of the powdery spores wafting down and put the container near a window. Up close for a north facing window, back a foot or so for south facing window (reverse this in the Southern Hemisphere).
5) Wait. It will be 6-8 weeks until you see anything. Then you will see small flat leaflike plants, "prothallia" that will grow to about 3/8 inches across. If there are a lot growing close together they must be thinned out to about 1 or 2 per 3" area. If not they will only grow male organs. During this time make sure the potting soil in the container does not dry out.. You should check the soil every week or so.
6) When the Prothallia get to 3/8" it will grow male and female organs. The male organ will make sperm which will swim to the female part and fertilize the egg. The egg will then grow into the fern plant that we see, called the "Sporophyte". During this time the prothallia should be sprinkled with water so that the sperm will be able to swim to the egg.
7) After another 6-8 weeks you will see little ferns come up; the first frond will be about 1/2" tall. Thin them out so they are about 3" apart.
8) In the spring give them a long time to adjust to the dry outside air by opening the top of your container a little bit each day. The open time should increase more and more for two weeks. If they look bad, close it up again until they recover, then try again. This is where I lose the most ferns; they have a hard time adjusting.
9) Plant them in a mostly shady spot, but not too shady. They are very fussy so keep an eye on them quite frequently for the first year."