Coat the bottom of a large pot with oil and place it over medium heat.
Give the oil a minute to heat up, and then add the onion, celery and carrots.
Cook the veggies, stirring occasionally, until they begin to soften up, about 5 minutes.
Add the garlic, curry powder, thyme, and turmeric to the pot. Cook everything for about 1 minute, until the garlic becomes very fragrant.
Stir in the cabbage, potato and broth.
Raise the heat and bring the liquid to a boil.
Lower the heat and allow the soup to simmer until the veggies are tender, about 20 to 25 minutes. Test a piece of potato by piercing it with a fork — it should give easily.
Remove the pot from heat and stir in the lemon juice. Season the soup with salt and pepper to taste.
Ladle into bowls and serve.