Blanch the cabbage and tomatoes in boiling water for 5 minutes. Drain, cut the cabbage into strips, peel the tomatoes and roughly chop.
Heat oil in a heavy saucepan. Saute onion 2-3 minutes. Add carrots, potatoes, zucchini, celery, cabbage and tomatoes. Pour over the water, season with salt and pepper, and add bay leaf and garlic. Simmer 45 minutes, uncovered.