How to Care for Bulbs
With a little tender, loving care, bulbs can do their thing and be wonderfully reliable. Bulbs come as a package of life — that is, with the embryonic plant and flower within, plus stored food to fuel the growth — they demand little from you, the gardener.
Watering your bulbs: Bulbs rot with too much moisture. And yet, they need water to generate roots and get growing. The trick is to grow bulbs in well-drained soil; they can use the water they need, and any excess moisture should drain away.
Fertilizing bulbs: Although newly planted bulbs have all the stored foods they need to perform the following spring, annual fertilizing can help keep this show going year after year.
A general-purpose fertilizer works fine for bulbs. A higher phosphorus content is often recommended simply because it inspires root growth as well as flower production. So go ahead and use the 5-10-5 or something close to this ratio.
People often recommend bone meal for bulbs, with its approximate formulation of 2.5-24-0. Alas, modern-day, store-bought bone meal is highly sanitized, and its benefits are questionable. Nonetheless, some bulb enthusiasts swear by it.
You need to fertilize only once, and you have three opportunities to do so:
At planting time (usually in the fall)
As growth starts, usually in early spring
The standard application rate for fertilizer is a tablespoon or small handful per square foot, but read the label on the fertilizer package for exact directions. Always apply fertilizer to damp ground, and water it in afterwards if there's no rain so it penetrates the soil and gets to the root zone.
Mulching: Mulch helps keep down weeds, can add organic matter to the soil, retains moisture, and stabilizes the soil temperatures. Stable soil temperatures are important so the bulbs don't sprout too soon and risk freezing damage from a late spring cold snap.
After bulbs bloom, the foliage tends to linger. Eventually it starts to yellow, then brown, and finally gives up the ghost — a process that can take many weeks. This stage is not a pretty sight, but don't interfere! The plant is busy sending food down to the bulb to fuel next year's show. Cutting off the leaves before they naturally die back diminishes next year's display.
Fighting bulb pests: The main predators of bulbs are mice and voles. Squirrels and chipmunks can dig up your bulbs. These rascally rodents are enough to make even the most mild-mannered gardener homicidal. Here are some strategies for keeping your bed of bulbs rodent-free:
Fill each planting hole with small, sharp gravel.
Make a "cage" of screen or hardware cloth, fill it with soil, plant your bulbs inside it, and then bury it at the correct depth.
Make a raised bed especially for bulbs. This bed should be about a foot deep. The bottom layer, at least 2 inches thick, should be small, sharp gravel. To accommodate the bulb's roots, at least 6 inches of good soil can go over the gravel. Plant the bulbs and cover with 2 inches of gravel or even sand. Last, lay a thick layer of mulch (up to 6 inches) of hay, pine needles, or shredded leaves over everything. Remember to rake off the mulch when spring comes.
Prior to planting, spray your bulbs with a foul-tasting repellent marketed for this purpose. Two common brands are Mole-Med and Ropel. Let the bulbs dry before planting. Castor oil is also a common, safe, and reasonably effect repellent that you can apply to the bulbs and/or the ground they grow in.