Moving to a new location? Or, maybe your daffodils have spread beyond the intended space? Or, maybe you want to share with others? The ideal time to dig up daffodils is about eight weeks after flowering, when the foliage has just started to yellow — and while you’re at it, you might as well divide the large-flowered ones. Small-flowered types can be left alone indefinitely, but most large-flowered daffodils must be divided every three to five years or you’ll end up with nothing but leaves.
Dig the new planting holes before you start, figuring that each old clump is probably getting overcrowded, should be divided, and so will need about three or four times as much space in the new location(s). Have extra soil and sod ready to fill in the old holes. Choose an overcast day, or work in the evening. Using a digging fork, putting it deep into the soil, cut a line around the clump about 2 inches from its outside edge. Keep working your way around, loosening the lifting, following the line you cut, until the whole clump is free. Lever it out, gently break it apart, and then work the sod away from the stems and set it aside for lawn repair.
Separate the bulbs, letting them fall naturally into smaller clumps that still have dirt attached. Don’t tear the roots — you can hose off the roots, disentangle them, and do a more thorough job of dividing. Plant in the prepared holes, and water well.
Save the fertilizer for the fall. By the time daffodils (genus Narcissus) bloom, their leaves are almost finished transferring the carbohydrates they’ve made into the bulb for storage. As the chlorophyll breaks down and the leaves turn yellow, the plants need only sunlight, air, and water to finish up.
If you need to fertilize daffodils, do it in early spring just as new growth pops up, or in the fall when roots are growing and daughter bulbs are being formed. Use a balanced fertilizer or well-rotted compost to maintain nutrition in situations where the bulbs are crowded or are permitted to set seed, which takes a lot of energy.
Many gardeners also hedge their bets by mixing a bulb booster into the bottom of the hole when planting bulbs, because it is high in phosphorus, which does not move much in the soil. Phosphorus encourages root growth, the first order of business for a newly planted bulb.