Add the lentils, carrots, potatoes, onion, garlic, curry powder, turmeric, and salt to the slow cooker.
Pour in the vegetable broth and half the can of coconut milk, then stir to combine.
Cover and cook on low for 7 hours until the lentils and vegetables are soft.
Stir in the spinach during the last 10 minutes of cooking so it wilts into the curry.
While the curry finishes, combine the rice, water, and remaining coconut milk in a medium saucepan.
Bring the rice mixture to a boil, then reduce to low, cover, and simmer for 15 minutes until the liquid is absorbed.
Fluff the rice with a fork and serve it alongside the lentil curry.