When To Fertilize Citrus In Az

If you’re growing citrus in Arizona, knowing when to fertilize citrus in AZ is the key to a healthy, productive tree. Getting the timing right helps your trees handle our extreme heat and produce those sweet fruits we love.

Our unique desert climate means a standard national schedule won’t work here. Arizona’s long, hot growing season and alkaline soils require a specific approach. This guide will walk you through the optimal calendar and methods to keep your citrus thriving.

The golden rule for Arizona citrus is to fertilize during the active growing season, which is longer here than in most places. You should start in late winter and continue through early fall.

The goal is to support flowering, fruit set, and the growth that happens during our intense summer. Stopping in fall allows the tree to harden off before any potential frost.

The Ideal Arizona Citrus Fertilization Schedule

Follow this simple timeline for the best results. It’s broken into three main applications with optional extras for young trees.

Late February to Early March: This is your first and most important feeding. It fuels the spring bloom and the initial push of new growth. Apply fertilizer just as you see new buds swelling.
Late April to Early May: The second feeding supports the developing young fruit and helps the tree continue to grow strong leaves to shade the fruit from our sun.
Late August to Early September: A final feeding aids in fruit maturation and provides nutrients that the tree will store for the next year’s growth. Do not fertilize after October 1st.

For trees under three years old, you can add one or two extra light feedings between the main dates, like in early June and mid-July. This supports there rapid growth phase.

Choosing the Right Fertilizer for Desert Soil

Arizona soil is often lacking in certain nutrients. Your citrus fertilizer should reflect that.

Look for a product labeled specifically for “Citrus & Fruit Trees.”
A balanced formula like a 20-20-20 is good, but one with more nitrogen (the first number) is often beneficial, such as a 24-8-16.
Crucially, ensure it contains micronutrients like Iron, Zinc, and Manganese. Our alkaline soil locks these up, making them unavailable to the tree, leading to yellow leaves.
Consider using a fertilizer that includes sulfur, which can help slightly acidify the soil over time.

Organic vs. Synthetic Options

Both work well if applied correctly. Organic options (like compost, manure blends, or citrus-specific organic mixes) release nutrients slowly and improve soil health. Synthetic granular fertilizers give a quicker nutrient boost. You can even use a combination for great results.

How to Apply Fertilizer: A Step-by-Step Guide

Doing it the right way ensures the roots can access the food you’re providing.

Water First: Always water the soil deeply a day or two before applying fertilizer. Applying to dry soil can risk root burn.
Measure Correctly: Read the label on your fertilizer bag for the recommended amount based on your tree’s size or age. More is not better.
Spread Evenly: Sprinkle the granules evenly on the soil starting about a foot from the trunk and going all the way out to the “drip line” (the edge of the tree’s canopy) and a little beyond.
Water Deeply Again: This step is essential. Water the area thoroughly after applying to wash the nutrients down into the root zone.

Signs Your Citrus Tree Needs Fertilizer

Sometimes, your tree will tell you it’s hungry. Watch for these clues:

Pale Green or Yellow Leaves: Especially if the veins remain green (a sign of iron chlorosis, common in AZ).
Poor Fruit Production: Very little fruit or fruit that drops prematurely.
Stunted Growth: New leaves and branches are smaller than usual or growth seems to have halted in the season.

Common Mistakes to Avoid

A few missteps can set your tree back. Here’s what to steer clear of.

Fertilizing Too Late: Applying in October or later can encourage tender new growth that will be killed by the first frost, wasting the tree’s energy.
Over-Fertilizing: This can burn roots, cause excessive leafy growth at the expense of fruit, and pollute groundwater.
Placing Fertilizer at the Trunk: The active feeder roots are out near the drip line. Fertilizer at the trunk won’t help and can harm the bark.
Ignoring Micronutrients: Using only a basic lawn fertilizer often leads to deficiency symptoms because it lacks the iron and zinc citrus craves in our soil.

Special Considerations for Potted Citrus

Citrus in containers need more frequent attention. They have less soil to draw nutrients from.

Use a slow-release fertilizer formulated for citrus at planting. Then, supplement with a liquid fertilizer every 4-6 weeks during the growing season (March through September). Always follow label directions for potted plants, as concentrations differ.

Watering: The Partner to Fertilizing

In Arizona, fertilizer is useless without proper watering. Nutrients need water to move into the roots.

Water deeply and infrequently to encourage deep roots. During peak summer, a mature tree may need a deep watering every 7-10 days. Adjust based on rainfall (if any) and temperature. Mulching around the tree with wood chips helps retain this crucial moisture.

FAQ: Your Arizona Citrus Fertilization Questions

Q: Can I fertilize my citrus tree in the winter?
A: No. Trees are mostly dormant in winter. Fertilizing then can disrupt their cycle and is ineffective as roots aren’t actively taking up nutrients.

Q: What if I missed the spring fertilization date?
A: Don’t panic. Just apply your first feeding as soon as you can, then adjust the rest of the schedule. It’s better to fertilize late than not at all, but try to get back on track next year.

Q: Is Epsom salt good for citrus trees?
A: Epsom salt provides magnesium, which can be beneficial if your tree has a deficiency (showing as yellowing between leaf veins). However, it’s not a complete fertilizer. Use it as a supplement if needed, not a replacement.

Q: How often should I fertilize a young, newly planted citrus tree?
A> Wait until you see new growth after planting, then begin a gentle schedule. Fertilize lightly every 6-8 weeks from March through September for the first two years to support establishment.

Q: Why are my tree’s leaves still yellow after fertilizing?
A: In Arizona, yellow leaves are often from iron deficiency caused by alkaline soil, not a lack of fertilizer. Ensure your fertilizer includes chelated iron, and consider applying a separate iron supplement according to product instructions.

By following this Arizona-specific schedule and tips, you’ll give your citrus trees the best foundation for success. Consistent care with the right food at the right time leads to resilient trees and bountiful, tasty harvests for years to come.