Another take.
Notice that $$-3+\sqrt4\lt-3+\sqrt5\lt-3+\sqrt9\Rightarrow\\\\-1\lt-3+\sqrt5\lt0$$
Since $$|0-(-1)|=1$$ is the smallest distance between two (different) integers, this is the required interval.
Another take.
Notice that $$-3+\sqrt4\lt-3+\sqrt5\lt-3+\sqrt9\Rightarrow\\\\-1\lt-3+\sqrt5\lt0$$
Since $$|0-(-1)|=1$$ is the smallest distance between two (different) integers, this is the required interval.