Prepare the vegetables: Chop the onions, garlic, kale, spinach, broccoli, cucumber, and celery into bite-sized pieces.
Sauté the aromatics: In a large pot, heat olive oil over medium heat. Add the chopped onions and garlic, sautéing until fragrant (about 3 minutes).
Cook the vegetables: Add the kale, spinach, broccoli, cucumber, and celery to the pot. Stir everything together for about 5 minutes, allowing the greens to wilt and the vegetables to soften.
Add the spices and broth: Stir in the ginger, turmeric, and a pinch of salt and pepper. Pour in the vegetable broth (or water) and bring to a simmer. Let it cook for about 15-20 minutes, until the vegetables are tender.
Blend the soup: Once the vegetables are soft, use an immersion blender to puree the soup until smooth. Alternatively, transfer it in batches to a regular blender.
Finish and serve: Stir in the lemon juice, taste, and adjust seasonings. Serve hot with your favorite toppings, like sliced avocado, fresh herbs, or sunflower seeds for added crunch.