I am trying to introduce native wildflowers to a west facing hillside that is currently just pasture grass and weeds. I am pulling out the blackberries and thistles but don't plan to do anything with the grass. I have a conglomeration of seed - a couple canisters of western wildflower seed, some crimson clover, and numerous containers of seed I've gathered this past summer/fall. I plan to just mix them all together and scatter them on top of the existing grass.

Two springs ago, we did have the hill down to bare dirt and I scattered a lot of seed at that time, but relatively few of them actually came up - likely because I didn't water it regularly.

Any thoughts on fall versus spring?

Fall is a better time, at least here in Texas, it gives seeds a chance to be stratified.

That's my thought as well, and I'm also thinking the winter rain will kind of beat the seed down through the grass. If we get snow, that will also push it down as it melts. That all makes sense to me...but my son (who works for a nursery) tells me to wait until spring. I might do half and half and hope for the best.

I agree about the Fall planting for cold stratification. I think it also depends on your rainfall patterns. You need good moisture for the seeds to germinate. Also, you need to scatter or sow late enough so that the seeds don't germinate until the following Spring. Now this is my advice. Others may feel differently.

Depending on what kind and how much grass there is, it has been my experience that the seeds won't do well in competition with a lot of grass. I've tried that before. I clear at least some patches down to the bare ground so that the seeds can take hold better there.

Because of some of the types of grass we have, it's very difficult for things to compete. I have had success with planting daffodil bulbs to naturalize as well. They come up and bloom in the Spring with no problem before the grasses really take off growing again. Also, wild violets can hold their own fairly well. At least they can here.

Because many benefit from the cold-either fall or at least by March.
You can seed onto snow too. I think the seeds benefit from winter moisture also.
Fall sowing sometimes risk loss to critters,but mulch can keep the birds from getting all the seeds.
Fall sowing also frees up time for other spring gardening chores.
Your idea to do half, and half is good.

Another advantage to the fall is, that is when many plants sprout. They form rosettes that overwinter ready to take-off in the spring.

Sowing onto snow lets me see how well I have distributed the seeds.

That's a good idea, Caroline. Do you have a large area for wildflowers?

No, I am on a city lot,but I sow them onto the flower beds.

I'm glad to hear you do that. I do the same thing.

I'm trying it all. I spread some in early-November after we had a fairly hard frost so the seed should not try to germinate early. I pulled some seeds from the garden last week and toss those around (echinacea, rudbeckia, and bee balm). If we get any snow this year, I'll spread some on top of that. And, finally, I plan to also toss some around early spring. I think I just need to make a concerted assault until things actually get established. I have a large area I'm trying to populate...