Few flowers are as easy to care for as tulips.
While not technically annuals, they often don't last more than a year or two. Replanting, therefore, saves the trouble of watering, fertilizing and other tasks season after season to guarantee the next year's growth. But a little bit of watering and feeding is never amiss during the right times.
New tulip bulbs are planted in the fall, to give them time to begin to lay down some roots before going somewhat dormant over winter. During this brief period they generally need no more water than is required to moisten the ground where they're planted. That soil should have good drainage, but it does help to supply some moisture when the tulip bulbs are first placed.
In the spring most climates will supply as much water as tulips need, indeed sometimes a little too much. Tulips evolved in the drier regions in Turkey and other Asiatic regions where the soil is a bit rocky and rainfall scarce, except in spring. As a result, they tolerate well any extended dry periods.
Melting snows will sometimes provide more than enough for tulips to grow rapidly once the warmer temperatures arrive. Spring rains don't necessarily harm that process, but flooding is possible if the garden isn't designed for good runoff. In areas that get little or no snow, and very low rainfall, supplementing the natural moisture in the air is helpful. The specific amount should always be modest.
When to water is a little more complicated, but not much more. Tulips come in various divisions (15 official ones, in all), but three broad categories can sum them up: Early, Mid-Season and Late. Examine the species you have to find out which it is, then supply water shortly before the growth spurt that precedes blooming.
Most tulips not in pots can get by with no fertilizer at all, apart from a small amount applied at planting time. This again is a consequence of the way they evolved in the wild, where the soil was poor. Overdoing it is much more likely, and has harmed more plants, than supplying too little.
For those that appear sickly, a little granular fertilizer is just the thing. Simply sprinkle it around the ground near the stalk and supply a very modest amount of water to keep it in place if necessary to prevent the wind blowing it away. It will leech slowly into the soil, ultimately reaching the bulb and roots. That gradual process is just what you want.
If you happen to have a particularly hungry species, spraying a little liquid fertilizer on the foliage is alright. Just ensure that it is diluted properly for your particular plant. Also, though tulips like hot, direct sun, sprayed fertilizer on the leaves can form tiny magnifying glasses that can burn leaves. Nitrogen, a common component of nearly all fertilizers, also encourages burning. Apply sparingly.
With only modest care, gentle watering and sparse feeding, your tulips grow strong and bloom beautifully for the two to four weeks they last.