Easiest is half-strength MiracleGro every other watering.

Happy New Year James,

Since my bulbs are in pots outside in full sun, and we tend to have wet springs, I put Osmocote on the soil surface when I first move them out in the spring so that they will have fertilizer available when they start to grow. I use 19-5-8 plus minors. Osmocote is rated in longevity based on a 70 degree F. soil temperature. Since we have a long growing season (March to November) and summer temperatures can be in the 90's and above I use an 8-9 month formulation. This way the fertilizer should be about done by drying down time in October and when they go into storage in November.

I supplement with liquid feedings during the summer when watering is required. Any soluble fertilizer that you add to water should be fine. Look for one that has a high first number in the analysis such as: 20-20-20, 20-10-20, 15-5-10, etc. There are a lot of good brands on the market. I use Peter's(which used to be owned by Scott's who also owns MiracleGro), and Jack's (who started Peter's before selling the company to Scott's). Since I may only liquid feed 2 to 4 times during the summer, I use a rate of 200 to 400 parts per million of Nitrogen. For 200 ppm N of a 20% Nitrogen fertilizer such as 20-10-20, that would be 13.33 ounces per 100 gallons of water or about 4 grams per gallon of water.

If your bulbs are indoors and only get water from you, then I would follow Kristi's advice and use a liquid feed. When you water be sure that some of the water drains out the bottom of the pots so that you get good leaching of the growing medium.