And if you plant tulips that don’t come back, there’s no need to fertilize, because there won’t be a next year for them.
If the soil needs phosphorus and potassium, use a complete fertilizer (such as 10-10-10, 9-9-6) at the rate of 2.5 pounds per 100 square feet, or 1 rounded teaspoon per square foot, Upham says. “If phosphorus and potassium are not needed,” he says, “blood meal makes an excellent fertilizer. It should be applied at the rate of 2 pounds per 100 square feet or 1 teaspoon per square foot.”
And of course be sure to leave the foliage alone until it dies naturally, because it sends energy to the bulb to also help next year’s bloom.
If salt has formed a crust on the surface of the soil, remove it, Upham says, not removing any more than 1/4 inch of the potting soil. You also may want to repot the plant at that point.