In a medium pot, heat coconut oil over medium heat. Add onion, garlic, and ginger, sautéing for 3–4 minutes until soft and fragrant.
Add zucchini, broccoli, and celery. Cook for another 3–4 minutes, stirring occasionally.
Pour in the water or broth and add turmeric. Bring to a gentle boil, then reduce heat and simmer for 10 minutes until vegetables are soft.
Stir in spinach and cook just until wilted (1–2 minutes).
Remove from heat. Use an immersion blender to blend until smooth, or transfer to a blender in batches.
Season with salt, pepper, and lemon juice if using. Serve hot, garnished with fresh herbs.