when to fertilize hyacinths
Next spring, as new growth emerges, fertilize with a balanced 10-10-10 or 10-15-10. Leave foliage until it has completely yellowed. Hyacinths prefer moisture during their spring growth but drought during their summer rest, so avoid planting water-needy, summer-blooming annuals over these bulbs. When hyacinths are forced for indoor bloom, their roots are quite shallow.