Today's Topic: When Should You Fertilize in Arizona? - 3 of 5 Part Series

Is It Fertilizing Season—or Does the Store Just Say It Is?

Walk into almost any garden center when the weather starts warming up and you’ll see it.

Bags of fertilizer stacked near the entrance. Displays promising greener lawns, healthier plants, and bigger blooms. Everything seems to be saying the same thing:

It’s time to fertilize.

But step outside and look around your own yard.

Your Bermudagrass may just be waking up. Your citrus may already be growing. Your flowering shrubs could be pushing new leaves, while some of your desert-adapted plants may not need fertilizer at all.

They’re all growing in the same Arizona yard.

But that doesn’t mean they’re all on the same schedule.

Your plants don’t read the signs at the garden center.

There isn’t a single day when every plant in an Arizona landscape suddenly needs fertilizer. What matters more is what you’re growing and where that plant is in its growth cycle.

Consider a typical Southeast Valley yard.

Bermudagrass loves the heat. As temperatures rise and the lawn moves into active growth, its nutritional needs increase.

Walk over to the citrus tree, however, and the story changes. Citrus is generally fertilized in several applications throughout the year rather than receiving everything at once. Even oranges and grapefruit can follow a different schedule from lemons and limes.

Then look at the desert-adapted plants. Many are perfectly happy growing in our desert environment with little or no routine supplemental fertilizer.

They may all share the same backyard, but they aren’t following the same calendar.

Why Timing Matters

Fertilizer is often treated like a quick pick-me-up: a plant looks tired, so we give it something to eat.

But that's not really how fertilizer works.

Fertilizer provides nutrients that can support growth. Apply it when a plant can use those nutrients, and you're working with the plant. Apply it simply because it's spring—or because the fertilizer aisle at the store is full—and you may be encouraging growth the plant doesn't need.

And extra growth comes with a cost. It may require more water, more pruning and more maintenance without necessarily producing a healthier plant.

So before reaching for the fertilizer bag, look at the landscape.

What are you growing? Is it actively growing? And is this the time of year that particular plant normally benefits from fertilizer?

The calendar can be a useful guide; however, the plant should have the final say.

What About Newly Planted Trees and Shrubs?

This is another place where homeowners can be tempted to fertilize too quickly.

You install a new plant and naturally want to help it get off to a good start. Reaching for fertilizer can seem like giving it an extra boost.

But newly installed plants are already adjusting to a major change.

Their first priority is establishing roots and adapting to their new environment. Depending on the plant, immediately adding fertilizer may not be necessary.

Before fertilizing something newly planted, find out what that plant needs and give it time to establish.

New doesn't automatically mean hungry.


Before you fertilize, ask yourself two questions:

What plant am I fertilizing—and is it actively growing?

Don't fertilize simply because it's March, April, or because fertilizer is on sale. If you're unsure about the right timing for a particular plant, find out before you apply anything.

The fertilizer bag doesn't know what season your plant is in. You need to.

Good fertilizing isn't about finding one date that works for the entire yard.

Your lawn, citrus, flowering shrubs, trees, and desert-adapted plants can have very different needs—and very different schedules.

The goal is to give each plant what it needs when it can actually use it.

Not sure when or whether the plants in your landscape should be fertilized? Esteban Land Design can evaluate your landscape and help determine what your plants may need before you start adding fertilizer.

Looking Ahead

You know what you're fertilizing. You've considered whether it needs fertilizer. And now you know when you fertilize matters. But then you walk into the store and see:

10-10-10.
16-4-8.
21-0-0.

What do those numbers actually mean—and which one does your plant need?

Next: What Do Those Numbers on the Fertilizer Bag Mean?