From Ground: First, water the hairy yellow vetch to dampen the soil, making it easier to remove the plant. Use a shovel or garden fork to dig a generous trench around the plant, ensuring you're far enough away to avoid damaging the root system. Pry the plant gently from the soil, lifting with the tool's lever action to keep the root ball intact.
From Pot: Water the hairy yellow vetch thoroughly to ensure the root ball slides out easily. Turn the pot sideways and gently tap it to loosen the plant. If the plant is stuck, you can gently squeeze a flexible pot, or run a trowel around the inside edge for stiffer pots, to help release the plant. Carefully pull the plant out by the base, supporting the root ball.
From Seedling Tray: Water the tray to moisten the soil, making it easier for the roots to slide out. Use a trowel or your fingers to push up from the bottom of the cell, or to scoop the seedling out from the top. Take care not to damage the tender roots or stem of your hairy yellow vetch as you remove it from the tray.