Interesting... I did a little looking and couldn't find any to order on line.
https://westernplainsseeds.com/productli ... atalog.pdf
are in Colorado and have this granular formulation:
Gro-Power Winterizer 2-10-10
GP00204 Gro-Power Hi-Nitrogen 2-10-10 20# bag
Strengthens Plants to Withstand Winter Environments
Aids in Early Spring Re-Growth
I don't know why they call it "Hi-Nitrogen" when they specify 2-10-10
the link gives their address and phone, you could probably order some by mail.
ebstone in Calif sells liquid Master Bloom 2-10-10
again they don't seem to give any way to order on line, but you could call them. Phone number is on the Contact Us page.