A simple piece of gear that will keep you comfortable, relaxed and able to focus is the sit pad.
It is a 12-18 inch square of closed cell foam - what people used to call "insulite". As the name suggests - the sit pad is for sitting. It provides some insulation from the ground and reduces convective cooling. It helps you maintain healthy body temperature and keeps you comfortable and thus, more able to relax and connect to nature.
If your body is burning extra energy and calories to maintain a safe temperature, you will feel a low level of anxiety and tension as you are essentially engaged in a kind of battle against what wilderness medicine practitioners refers to as a "cold threat".
If you sit on cold earth you will lose heat. You will be battling hypothermia and this will drain your energy. It will not be pleasant.
Many of the activities in the Returning To Earth curriculum are slow and quiet, involving extended periods of observation and solo sitting. Thus, maintaining body temperature, especially in winter, is critical. The sit pad buys you extra time and makes you more comfortable out there. With that extra time you will be able to slow your thoughts, breathing, and be relaxed enough to connect more deeply to the wisdom and healing power of the Earth.
You can usually find closed cell foam sleeping pads in the camping section of any large department store or in Army surplus stores.
In order to connect to the Earth we sometimes have to be insulated from it. Especially in winter.
Get a sit pad. You'll be glad you did.