October is the month that existing beds of spring-flowering bulbs such as daffodils and tulips are fertilized. If bulbs have been fertilized in the past, there is often plenty of phosphorus and potassium in the soil though it is best to take a soil test to be certain. If the soil needs phosphorus and potassium, use a complete fertilizer (such as 10-10-10, 9-9-6, etc.) at the rate of 2.5 lbs. per 100 square feet. This would equal 1 rounded teaspoon per square foot. If phosphorus and potassium are not needed, 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. Turf fertilizers such as a 27-3-3 or 30-3-3 can be used, but cut the rate by a third.
If there is difficulty in determining exactly where the bulbs are planted due to the lack of foliage, fertilizing in the spring rather than the fall is acceptable. However, it is important that the plants are fertilized when the foliage first shows. Waiting until the bulbs are flowering is too late as the roots have already begun to shut down. (Ward Upham)