Importance of bone meal and bulb food
We recommend bone meal at the time of planting, then applying a balanced bulb food once the foliage appears above the soil line in late winter/early spring.
There are a couple of reasons for this. Nitrogen can burn the actual bulb, which only needs the phosphorus and potash from bone meal in order to stimulate rooting. But once the bulb is sending out a stem, it needs nitrogen to become strong so it won’t bend over from the weight of the flowers that it sets. This is especially important for bulbs with large heavy flowers, such as tulips, ranunculus, and hyacinth.
It’s also important to dig the holes or trenches a little deeper than the bulb needs to be, applying some bone meal below the bulb, then a little more soil so the bulb doesn’t sit directly on the food but has access to the food as it sends out roots (got to give those roots some incentive to stretch).