I finally got done exploring, building, and growing crops in a snow biome underground. Try to do it dead center of the snow area. I dug a cave like hole but first cleaned the area of bears. Single player, survival mode.
The layers I went through were snow (cannot be harvested), mud (look at everything crafting, useless), the stone. I was surprise to find the deeper I went in the ground, the colder it got vs the surface. Same effect at snow at night for temperature. Was wearing warmth cloth set but hat that gave 50 insulation, still got cold.
Once I had enough mats for building workbench and block bench, outside until I had large underground area. I built the ceiling under the mud layer. So I will not poke holes above to the surface. 5 blocks inside with floor and ceiling was total of 7 blocks. Instead of mining too wide of a place, I went down and made a large underground floor. I had a rock path so I can make blocks or dump stuff in a chest. With the main area done with walls, ceiling, floors, and ramp. The ramp connected up to a door that was ground level. Angle tunnel with ramps. Ramps where the floor and ceiling. Threw some windows with glass for light. To finish off the lower floor was very deep, no walls on the side, just bare rock. 3 pillars for the ladder (3 ladder parts to get out). Standard with crafting stations and water thrown in the corner. For the drinking water without using a canteen. Lightning torches/lights.
Underground farming/garden. I ran back to my main house and grab lots of dirt and other mats/items. I put the dirt down on the top the stone. This was the tricky part If you use the rake or hoe too much, you hit the stone and have to start over. Little hilly but mostly flat. I planted crops that keep growing and harvesting them. I did corn, strawberries, and tomatoes. Then hunted down a cherry tree and apple tree. The area was big enough to plant fruit trees, meaning height wise. When I planted everything I notice everything is a brownish yellow color. Still waiting on the fruit trees but the vegetables are that color even when ripe. Seem like a lot slower to grow. Torches for lighting.
I made a above ground tower which had issues dragging blocks to build many. 90% of the time was one block build unless filling in walls. Ceiling was glass windows with window frames. Base of the tower, put 2 statues and Christmas tree.
Temperature. With no heaters or campfires, underground was colder than surface expect at night, the same. The main room had a campfire and radiator heater which gave enough heat to wear starter clothes without get cold. Once you walked outside, you froze. For the garden area, about the same size as above floor but deeper. Found cold areas which needs more heaters.
Takes away do build/make but snow biome underground house ready to live in and watch the snow come down. Also give you that Christmas feel during the winter time.