Growing Plants From Seed
There are certain things that need to happen to most native seeds to break their dormancy and coax them into germinating. The reason seeds become dormant, is to prevent them from germinating in the wrong season. Imagine if they germinated in the fall, they wouldn't have time to establish before the onset of winter. Seeds also won't germinate in the summer when it's too hot and the seedlings wouldn't survive.
Cold moist stratification is the process that seeds go through in the winter months. The moist freezing and thawing breaks the seeds dormancy and allows them to germinate in the spring. Most species need about 45 days of cool temperatures (30 to 40 degrees) to break dormancy.
Cold dry stratification is similar to moist stratification except the seeds only need the cold temperatures to break dormancy. Most native grasses need this type of stratification, although moist stratification also works for them.
Scarification is the process of scratching through the hard protective seed coat so they can germinate. Some seeds - in the bean family mostly - need scarification. This can be done by using two sanding blocks and rubbing the seed between them using medium grit sandpaper. For larger legume seeds you can also use a file to nick the seed coat. If you don't scarify some seeds, it may take them many years for the seed coat to weaken and allow germination.
Seeds can be planted directly in their permanent location, in transplant pots, or in a temporary seeding bed.
Cover the seeds with soil to a depth of twice the diameter of a seed. For very small seeds just plant on the surface, with a light dusting of soil. It's better to plant too shallow than too deep. Some species need light to germinate, another good reason not to plant them too deep.
Be sure to use a seeding soil mix if planting in transplant pots. It's best to water from the bottom (pour water into the seedling tray) to let the pots soak up the water. If you try to water from the top (by sprinkling water over the seeds) the seeds may get washed away.
Planting seeds outdoors in a permanent location
You can sow the seeds directly where you want them to grow. But when doing this, they will have to compete with established plants and weeds. If you have a weed free site, this can be successful.
This method can be used no matter what the season. If you plant in fall or winter, they should germinate the next spring. If you plant in spring, summer, or fall, they will germinate the following spring.
Planting seeds outdoors in seeding beds
You can stratify the seeds naturally by planting them outdoors in the fall or winter (November thru early March).
If using an outdoor seeding bed, plant the seeds in rows, so you can distinguish seedlings from weeds when they germinate.
If it's a very dry fall or winter, watering the seed bed occasionally may be necessary to promote stratification - normally this is not a requirement.
Once seeds have germinated be sure to keep them from drying out by watering them.
Planting seeds outdoors in transplant pots
Use this method if planting in fall or winter to naturally stratify the seed.
Keep the pots outdoors. Water the pots well and cover them with a sheet of plastic to keep them from drying out. When spring arrives the plastic can be removed.
If you aren't able to cover them with plastic, be sure to keep them in a shaded place where they won't dry out so quickly. You may have to keep them moist if it's a dry winter. Keep the pots in a shaded area until they germinate.
Planting seeds indoors in transplant pots
If it's spring or summer (late March thru July) and you missed out on planting in the fall or winter, you can stratify the seeds artificially. Just mix equal parts moist sand with the seeds directly in their plastic packet. Place the packets in the refrigerator (not the freezer). After about 45 days you can plant the seeds indoors in pots. Don't worry about the sand, it can be put in the pots with the seeds.
Germinate the seeds indoors, because the indoor temperature is optimal for seed germination. Outdoor temperatures tend to be too warm to promote seed germination.
Transplanting your seedlings
When the seedlings have two or three true leaves, they are ready for transplanting into their permanent location.
Be sure to water the seedlings after transplanting. Keep watering them until they are established - usually for a couple weeks. Mulching is helpful to keep weeds down and conserve moisture.
Many plants will flower their first or second year from seed!
Preparing a bed for seeds or seedlings
If you are directly sowing your seeds or putting your seedlings into a new bed be sure the soil is bare (nothing growing in it). If you don't have an area that is bare, create one by using Roundup to kill the grass and weeds. Or use something like black plastic to smother the grass and weeds.
Growing natives from seed can be a bit more laborious than buying plants but it's much more cost effective. Plus the results can be very satisfying. I find great satisfaction in seeing tiny seedlings emerge after coaxing the seeds out of their natural dormancy. Good luck growing your native wildflowers and grasses from seed.