If using raw wood you have to prime it first or if the wood has been painted but the original paint is in bad shape. Exterior latex will just soak in and won't be stabilized enough to hold the next layers of paint. I tried to tell my husband this about 20 years ago. We were painting some cedar siding. After putting 4 coats of exterior paint on the building, he gave in and primed it. Then it only needed one coat of primer to finish the process. That was a very expensive paint job. "smile" There are some paints now that have the primer and final finish in a one coat paint. I haven't tried it so don't know how good it is.
Kalamaquilts…..that is beautiful. You are sew talented.