I put about $10,000 into my kitchen (granite, appliances). How can I keep my landlord from raising the rent?

I put in granite counter tops, tile flooring, new cabinetry and new stainless steel appliances. Once my landlord sees he sees how nice it looks he's probably going to raise my rent, but that doesn't seem fair. How can I stop this? Also, I just rent month to month, so he can kick me out at any time. Should I be worried?