Tie the thyme together with a piece of thread or butcher's twine.

In a 5-to-6qt slow cooker, combine the parsnips, turnips, carrots, rutabega, celery, garlic, onion, thyme, barley, 8cups of water, 1tsp salt and 1/4tsp pepper.

Cook, covered, until the barley is cooked through and the veggies are tender. 6-7 hours on low or 4-5 hours on high (if cooking on high, use only 6cups of water)

When the soup has 10mins left to cook, remove the thyme

Turn the slow cooker on high, add the chard and cook, covered until tender, 5-7 mins.

Serve with Parmesan, if desired