I think you can sow the poppies into the existing meadow. I would consider spot sowing into places where there is a little open soil or thinner grass, perhaps with a little raking or hoeing to break up the soil, then spread the poppy seeds on top. You won't have to sow all that much of the meadow for it to look nice when the poppies bloom - if you can find 10% of the meadow to sow poppies, that would be a really nice show in the spring. Even 5% would be pretty nice, I think. Most of the time when you see a really brilliant show of wildflowers, if you actually go out and check how much of the space is taken up by the plant the flowers are coming from, it really isn't much of the space.

I'm new to this entire process, however, ripped up an established field to 'properly sow the seed' last year. I used a combination of an annual and perennial seed mix.

WOW! Was I sorry!

I had barren sandy loam, and wildlife feasting on the seed!!! In the end, I had an occasional annual that popped up. What a disaster!

This spring, I'm going to re-seed. I'll never, ever pull out the existing vegetation again. I will sow over the field w/ the new seed and hope for the best. I can live w/ the prairie garden look over barren, dusty ground any day!

Spot sowing is the key, with localized areas of preparation.