How to Fertilize Bulbs
Love bulb gardening and wonder how to fertilize these beauties? You’re in good company—many people get confused about this and wind up overfertilizing (more on that in a minute). So we went to the top and asked Easy to Grow Bulbs’ owner Jim Threadgill about how to properly fertilize, because we’re pretty sure if Jim doesn’t know, nobody does. Spoiler alert: Jim knows.
Wait a sec. Don’t bulbs have everything they need in their bulb?
That is a great question. Bulbs are those sparkly unicorn plants that do, indeed, have what they need stored inside, but they need a little bit of help from us at various points along the way in order to do their job. When we fertilize bulbs, we encourage them to first generate and then store their “food” for their coming flowering and display.
The bulb has a new shoot as well as fleshy scale leaves inside, and during the growing season, the plant uses food that is stored in these fleshy scale leaves. At the end of the season, these same leaves channel food into new scale leaves for the next season’s flowering. Like magic.
So, when do I fertilize?
First, it’s important to fertilize when you plant the bulb. And you don’t need anything fancy, Jim says, so don’t overthink it.
- Use a good, balanced fertilizer (10-10-10, for example).
- The brand isn’t as important as the balance of nutrients.
- Plant the bulb first, then apply fertilizer on the soil surface.
- Avoid putting fertilizer into the planting hole itself, which can burn bulbs.
- Water in after fertilizing.
Then, let it be until you see new shoots emerging—and at this point, you can fertilize it again. Think of it as a welcome gift for showing up to the party, like when the host puts a cocktail in your hand when you walk through the door. Kind of makes you want to stay and enjoy yourself, doesn’t it?
What kind of fertilizer do I need?
Aside from the fertilizer being balanced (meaning it has an equal ratio of nitrogen, phosphorus, and potassium) as noted above, Jim says, “It doesn’t really matter—the most important thing is that it’s balanced and you get on a schedule with it.” So, use what you have on hand, like:
- A water-soluble fertilizer
- A granular or slow-release fertilizer
Pretty simple, right? We like simple over here. No need to complicate things.
You may have heard this before, but it bears repeating. Never over-fertilize any plant, including your bulbs. There is, indeed, something called “too much of a good thing.” This is where well-meaning gardeners get themselves into a jam. They think, “Hmmm, if a little fertilizer is a good thing, then a lot of fertilizer must be even better!”
You know how a bowl of ice cream hits the spot and addresses your sweet tooth craving? What if you ate an entire gallon of Rocky Road? What if you ate ice cream all day long? You wouldn’t feel too great, would you? A little goes a long way, friends, so read the label and stick to the application amounts and the directions that come with the product.
Now, that being said, once you know the rules, you can judiciously break them. For example, Jim likes to sometimes take a water-soluble fertilizer, cut the application rate in half, and then feed his bulbs every couple of weeks rather than once a month or once during the growing season. This method gives your bulbs a regular feeding without overindulging, like having a little bit of ice cream once a week rather than a bowl once a month. And just to be clear, we’re not judging if you have a bowl of ice cream every week, but your bulbs will certainly judge you if you overfeed them.
- Katie Elzer-Peters