There are several hot springs around Alaska and most have been used at one time or another for gardening. The ground around the springs usually stays frost-free year-around and the warm water was used for irrigation.
One example is Pilgram Hot Springs (originally called Kruszgamepa Hot Springs) which is located on the left bank of the Pilgrim River some 60 road miles north of Nome. In the days of gold mining on the Seward Peninsula (1989-1918), the property was a recreation center for miners attracted by its spa baths, saloon, dance hall and roadhouse. A fairly large area around the hot springs is free of permafrost and was used for gardening/agriculture starting in the 1890’s. First the produce fed the miners in and around Nome. Then the roadhouse and saloon burned down in 1908 and the property was giving to Father Lafortune who turned the ranch into a mission and orphanage around the time of the 1918 influenza epidemic. Now the farm and gardens of the mission helped to make it, in large part, self-supporting.
Gardening was conducted around other hot springs in Alaska as well. The below images are from Manley Hot Springs from around the same era.
Corn needs warmer soil temperatures than we currently have in Alaska (outside of the hot springs areas that is) but according to work done by Nicole Swenson for her master’s project the soil temperatures in Alaska are predicted to rise. She used SNAP projected air temperature data in a modified soil thermal flux model and projected soil temperatures to the end of the century. So corn might become a viable crop in these latitudes in the not so distant future.
And below is an image from an interior view of a greenhouse in the Tanana Valley (if you look closely you can see a squash with “Caro Hot Springs” carved onto its surface):