Americans still haven't celebrated our secular harvest holiday yet (Thanksgiving)-- which marks the unofficial change from autumn to winter, even if the official shift falls on the Solstice. So I think it's still appropriate to honor Freyr, especially at lower latitudes.
Some seasonal-appropriate offerings:
alcohol (mead or honey wine, barley liquor, and golden wines work nicely)
honey or maple syrup (raw honey with pollen is more potent)
grain (barley, cracked wheat, oats, a prepared bowl of oatmeal or a sheaf of grain)
late harvest fruits (such as apples or persimmons)
bread or baked goods
incense (masculine and earthy, can be slightly sweet; cedar and piñon work well)
yellow flowers (chrysanthemums, late roses or sunflowers)
a "corn dolly", wheat weaving or wreath (golden ribbons are excellent)
Offerings that you've grown or made yourself work best; if you can't grow flowers, potted ones that you can plant later are appreciated. To dedicate an offering, you can simply place it on an altar or private place outdoors and say, "I dedicate this offering of [x] to [x]."
I was gonna kick off my month for Pop with a more general post on how awesome He is, but I came across this on the blogosphere, and I wanted to quote it, because the blog it's from is about health at any size.
"When I started out, I felt like I should post every comment that wasn’t just overt spam. I believed that it was somehow cowardly to not post hater comments. I have since changed my mind – I work hard to put out good information on this blog and develop a readership and I don’t have to hand that forum over to a hater to prove anything. People are allowed to behave like idiots but I’m under no obligation to give them a place to do so."
I talk a lot about the self-work I do with Loki, but Pop is the flip side of that work - Loki does a lot for my mental health, but Pop is all about me taking care of, and taking pride in my physical body, and in showing me how my attitudes toward the physical affect the spiritual. When I did my shadow work (ha ha like that's EVER done) on my body, the kind of words I came up about were things like, "polluted. defiled. weak. debased. dirty."