I was sadly poorly planned this past year--most of what I have planted bloomed in the fall. I'd like to have pollinator-friendly blooms available spring to fall. I don't have my list prepared yet (I want to make them all native or at least local).

I'm located on Long Island, NY (USDA 7a). My hope was to start seedlings indoors for planting when appropriate so that I'll have decently-sized plants ready to bloom, starting in the spring (for spring-blooming plants, of course). Will starting them indoors screw up their blooming schedules? Is there a better time to start seeding indoors?

Hi, sorry you havent any answers yet.
I dont think you will screw up their bloom time. Annuals should bloom earlier if you start them earlier. I use the packet guidelines of eight weeks and mine are still much smaller than what is available as starter plants in May.
Have you done indoor seeds before?

Columbine can be seeded outside in fall so they stratify and grow early.

Some plants bloom in regard to day length, and some in regard to maturity.

I would research each plant that you want to grow.
The data base might be helpful or just ask questions here?
There are seed mixes which are for pollinators and for regions too.
Some seeds may need to be sowed outside in the fall.