Bulbs are really good at storing food. Nevertheless, they sometimes need a little push at the right time to guarantee a rich growth. The idea here is to get the fertilizer below the bulb. Timing is essential to get the bulb to absorb the nutrients more efficiently.
What type of fertilizer should I use?
This will basically depend on the type of bulbs you are planting. Two very typical spring bulbs are tulips and daffodils. They are strong bulbs and, if fertilized appropriately, they will give you the best flower display in spring. Experts recommend using a 10-10-10 or 10-15-10 fertilizer. You should use granular instead of liquid since these will stay longer in the soil. Longer is better than faster.
When is the best time?
The best time to plant them is during the fall. But then they should be fertilized in spring. When planted, add several inches of organic compost with some mild synthetic fertilizer. The dressing with the fertilizer described should be done at this point. Be careful not to be excessive since this might burn the bulbs. This means that maybe you not put fertilizer inside the soil.
When new shoots appear in spring, apply the same fertilizer again. Always be careful to follow directions before applying.
The main purpose of fertilizers is to help bulbs produce and store food that they will be using for their spring flower display. But to get optimal results, one should not only take care of timing but also of the proper amount.
Even when bulbs might respond differently to fertilizing times, the general trend for fertilizing bulbs would be: Established plants should be fertilized in early spring. New planted bulbs should be fertilized on growth in the fall.