Bulbs are such a leap of faith. We plant them months before we expect to see them and then forget all about them. But just when we need them, they pop out of the ground and remind us in the most delightful way, that spring always follows winter.
The snowdrops have done their thing, the daffodils are now stealing the limelight, highlighted by cheerful grape hyacinths and coy crocus. Is there anything they need from us? Maybe some fertilizer?
Do You Need to Feed Your Bulbs?
Not necessarily. Many bulbs can fend for themselves for years. It’s really hard to kill a daffodil. If you have great soil, that’s all a plant really needs. But how many of us have naturally great soil?
It takes a lot of energy to bloom. Those fat bulbs you planted last fall have not been sitting completely idle. They used some of their stored food to send down a healthy set of roots last fall, to establish them for years to come.
When spring comes and the bulbs sprout and push their way toward the sun, the remainder of their stored energy is pretty much depleted. They can recoup a good deal of it if you let the leaves die back on their own. All the photosynthesis they undergo puts carbs back into the bulbs, to get them through another period of dormancy, and prepares them to bloom again next spring.
Leaving the leaves is the most important thing you can do. And don’t braid the leaves or fold them into tidy bundles. You want as much of the leaf exposed to glorious sunlight as possible. Don’t worry, they won’t be ugly for long. Once they start turning brown, their work is done and you can remove them. Most of the time, nearby plants have long since filled in and you barely even notice the fading leaves.
The bulb is doing everything it can to stay healthy and extend its life. If you want to help it along, give it a boost with some bulb food..
The bulb experts all have their preferred bulb feeding times. Most think it’s a good idea to feed them in the fall, when you plant them. Some say to feed them when they first sprout, in the spring. And others think the perfect time is as the flowers are fading and the bulbs are putting their energy into plumping up again.
I don’t know anyone who is that diligent when it comes to feeding their bulbs. Since fertilizer can take awhile to become accessible to plants, the best time to feed is probably when the bulbs are first sprouting. That’s when they are actively growing and starving. If you can’t run out there in time for that, it’s fine to feed them at flowering.
What Should You Feed Them With?
Bulb food is basically phosphorous (the middle number on a bag of fertilizer, such as 5-10-5). Of course, bulbs need all the essential nutrients, just like any other plant. But when you are trying to beef up roots and encourage flowering, phosphorous is the primary need.
Bone meal has long been recommended as another good source of phosphorous and a great bulb food. Unfortunately modern bone meal is steam-cleaned and loses most of its nutritional value in the process. Yes, there was a time when bone meal was simply ground up fresh and offered to gardeners, but those days are gone. While it was nice to recycle a byproduct, if you’ve ever used bone meal or blood meal in the garden, you know they can attract animals like skunks and the neighbor’s dogs, that will dig up your bulbs in pursuit of the meal. So stick with bulb food.
Phosphorous is a lazy nutrient and takes its sweet time working its way down into the soil, if it ever makes it there at all. If you are using a granular fertilizer, sprinkling it on top of the soil as a side dressing isn’t going to be terribly effective. Better to scratch it into the nearby surface. Just be careful not to get too close to the roots.
Water soluble fertilizers will have a faster impact, but a shorter duration. However since feeding bulbs is just a supplement to their own ability to create and store food, either type of fertilizer will do.
If you’ve been feeding your bulbs and they still seem to languish, it’s time to test your soil pH. Most bulbs like a pH between 6.0 and 7.0 and a lot of soils in the Hudson Valley are more acidic than that. If the soil pH is far too high or low, the bulbs won’t be able to access the nutrients in the soil, no matter how much you feed them.