Sort green peas and remove whatever does not look like a pea. Rinse in cold water until water is clear.
Finely dice the carrots, onion, celery, garlic and put aside.
In a deep and large sauce pan add a couple of tsp of olive oil and place on medium heat. When oil is warm start by adding the onions, then the garlic, when soft and slightly brown remove from heat.
Add 3 quarts of cold water slowly to the pan.
Place back on medium heat,
Add the carrots, celery and the peas. Stir and cover.
Stir and check frequently while you sort and rinse your barley. Add to pan.
When soup looks thoroughly heated start adding seasonings, (start slow and add to taste.)
Lower heat to a light simmer so that flavors slowly develop and your pan does not go over, you may need to keep the cover slightly off.
When all ingredients have dissolved into each other take the zucchini and peel it and then cube it into small thin pieces and add to the soup.
When the zucchini has dissolved into the soup you know it I done. Continue to taste and season.
Add a couple of sprigs of fresh parsley and remove from heat. Cover and let it sit for several minutes.
Remove parsley sprigs and do a final taste check.
Serve with a dollop of sour cream or yogurt.