Looking for care recommendations for my son’s grapefruit plant. He planted a seed from a store bought grapefruit about two years ago and it had miraculously stayed alive. But it’s hardly grown at all and it doesn’t look very happy. What do we need to do to help it thrive (we live in NYC with only one window that gets much sunlight, for context. We do have a small outdoor space, but anytime I’ve put something living out there it’s destroyed by squirrels almost immediately.)