From Ground: Start by watering your sweet spurge plant to soften the ground, making it easier to dig without damaging the root system. Use a shovel or spade to dig a wide perimeter around the plant, ensuring you're beyond its root ball. Carefully work the spade under the root ball to lift the plant from its original location. Keep as much of the soil intact as possible to preserve the root ball.
From Pot: Water the plant slightly an hour or so beforehand. Turn the pot upside down and gently tap the bottom the plant should slide out with the soil attached to the roots. If the plant is stuck, try squeezing the sides of the pot to loosen the soil, never pull the plant out by the stem as it can cause serious injury to the plant.
From Seedling Tray: Fill a small container with water, then dip the bottom of the tray in the water to loosen the soil. Carefully lift each sweet spurge seedling by the leaves (not the stem), making sure to get as much of the root system as possible.