Daffodils are one of the first flowers to appear in spring. To protect bulbs against cold winter temperatures, they need to be planted deep enough to protect the bulb but not so deep that the bulb has trouble germinating at the right time. Plant daffodil bulbs when the soil temperatures are cool enough that the bulb will not emerge too soon, but warm enough that the bulb can develop a good root system before the ground freezes.
Daffodil bulbs vary in size. The larger the bulb, the more expensive it will be. Larger bulbs need to be planted deeper in the ground than smaller ones. Provide adequate space between bulbs so they have enough room to grow. The University of Illinois Extension recommends that you plant smaller bulbs at a depth of 4 inches and larger bulbs at 8 inches. It further suggests that a good rule for planting bulbs is to bury them at a depth that is two to three times their height, pointed side up. The Iowa State University Extension suggests planting smaller bulbs 3 to 4 inches below ground, and larger bulbs 6 to 8 inches deep.
Daffodil bulbs need to be planted in the fall, a few weeks before the first hard frost. This gives the bulbs time to get established before the ground freezes. Some hybrids are more sensitive than others and need time to acclimate to the environment. Bulbs should be stored in a cool and dry place until you are ready to plant them. If you live in Northern climates, bulbs should be planted in September or October. Southern areas should plant from October to November.
Select bulbs that are firm and unblemished. The Iowa State University Extension recommends planting daffodils in clusters of at least 10 bulbs to create the best visual effect. Healthy bulbs that are planted at the proper depth will produce beautiful flowers and multiply faster.
Several tools on the market will help you plant daffodil bulbs at the correct depth. Bulb planters and augers that attach to drills can help you get through difficult soil. When you are planting daffodils, it is a good time to add fertilizer and put a light layer of mulch on top of the soil. Fertilizer will help plant growth, and mulch will help keep soil temperatures consistent.
Once bulbs have been planted correctly, they should be watered frequently before the first frost to encourage good root development and remove any air pockets that are around the daffodil bulbs. Mulching will also help the soil retain its moisture.