Good morning, i am building a new small greenhouse in 8B. Typical winter lows 25°F. Max winter low in the past 30 years 13°F. The greenhouse is 9x10 x14" high at the peak. Hand built. Couldn't find a kit with the dimensions I wanted. Dirt floor with no perimeter frost wall. We typically don't get any frost in the ground at all.

Can I grow kumquats in the ground here inside the greenhouse?

We have a sad Meiwa kumquat for the past 3 years in a pot. I have an outdoor shed with a few windows that I have kept zone 9's alive over winter, for the past twenty five years. Small electric oscillating heater used to keep it just above 36°F.

Very excited to finally have the greenhouse. I am willing to devote a large portion of the greenhouse to the kumquat. Should I get an additional one? I am looking at the Fukushu kumquat as well. Thank you for any suggestions.