When to fertilize what — built for Phoenix yards.
Pick what you're growing to see a category-based, low-desert seasonal planning guide. Each entry is a review window—not an automatic application. Feed only when the plant, site, evidence, and product label support it, then print the guide, download a PDF, or ask AE about your selected plants.
Planning guide, not a diagnosis: this tool does not analyze your soil or identify a plant problem. Product form, amount, and watering depend on the plant, product label, soil, irrigation, and site. Do not treat water stress with extra fertilizer.
Step 1 — Pick what you're feeding
Choose one or more categories. The low-desert seasonal review guide below updates instantly; it is not soil analysis or a personal diagnosis.
Edibles & fruit
Trees
Desert & native
Shrubs & ground cover
Flowers & roses
Turf
Step 2 — Your seasonal review guide
4 months with review items for the categories you selected.
February
1 review itemCitrus
edibles- Consider
- Consider a labeled citrus fertilizer if annual nitrogen is warranted
- Amount
- First of three equal portions of the species-specific annual total; calculate product amount from tree size and product nitrogen percentage using the UA chart
- Why
- February represents the Jan–Feb first window for all listed citrus; it is one review point, not a whole-year quantity or monthly dose.
- Watering
- Apply only by the label and match irrigation to soil and the established root zone; do not feed a water-stressed tree.
April
1 review itemCitrus
edibles- Consider
- Consider the same labeled citrus program after reviewing growth and prior feeding
- Amount
- Second of three equal portions of the species-specific annual total; calculate product amount from tree size and product nitrogen percentage using the UA chart
- Why
- April represents the Mar–Apr second window for all listed citrus; it is not the whole-year quantity in one feeding.
- Watering
- Follow product watering directions and avoid extra fertilizer as a response to wilting or irrigation problems.
May
1 review itemCitrus
edibles- Consider
- Oranges, tangerines, and grapefruit only: consider the chart's final annual fraction
- Amount
- Final species-specific fraction for oranges, tangerines, and grapefruit; lemons and limes use September instead
- Why
- May represents the May–June final window for oranges, tangerines, and grapefruit; lemons and limes use Aug–Sep instead. This is an alternative species window, not one of four automatic feedings.
- Watering
- Use the label and site irrigation plan; keep fertilizer off trunks and hardscape.
September
1 review itemCitrus
edibles- Consider
- Lemons and limes only: consider the chart's final annual fraction
- Amount
- Final species-specific fraction for lemons and limes; oranges, tangerines, and grapefruit use May instead
- Why
- This is the Aug–Sep alternative final window—not an extra fourth feeding.
- Watering
- Apply only to a plant with adequate moisture and follow label directions for watering-in.
Three checks before feeding
- Confirm the plant actually needs nutrients. Identify the plant and review growth, symptoms, prior feeding, soil information, and the product label before applying anything.
- Correct water, root, heat, or planting stress first. These problems can look like nutrient shortage, and extra fertilizer does not fix them.
- Use the right product, amount, and application method. Granular or liquid depends on the plant, product, soil or growing medium, irrigation, and site. Follow the label and water accordingly.
Want the full version?
The Guardian Fertilizer Planner uses your saved plant inventory and profile notes for soil pH, irrigation, sun, and microclimate to add review checks. AE staff can review plan items and record changes. Ask us which Outdoor Guardian care options fit your property.
Learn about Outdoor GuardianCommon fertilizer questions
When should I fertilize citrus in Phoenix?+
Three fixed dates and a trunk-diameter formula do not fit every citrus tree. Arizona guidance divides the annual amount by citrus type: oranges, tangerines, and grapefruit use Jan–Feb, Mar–Apr, and May–Jun windows; lemons and limes use Jan–Feb, Mar–Apr, and Aug–Sep. Calculate product amount from tree size and the product's nitrogen percentage using the linked University of Arizona chart.
Should I fertilize my mesquite or palo verde?+
Healthy desert-adapted trees usually do not need routine fertilizer. Pale leaves or weak growth can also reflect irrigation, roots, soil, pests, or other cultural problems, so identify the cause before feeding. Extra growth can increase water and pruning needs.
Why do palms need a special fertilizer?+
True palms have species-specific nutrient needs, and an 8-2-12 analysis with magnesium and micronutrients is one published example—not a universal cure for yellowing or frizzle-top. Diagnose symptoms, follow a palm-labeled product, and remember that sago is a cycad rather than a true palm.
Can I fertilize my Bermuda lawn in winter?+
Dormant Bermuda does not need nitrogen. In the low desert, review actively growing Bermuda from April through October; a common maintenance reference is 0.5 lb of actual nitrogen per 1,000 square feet per month, with product weight calculated from its nitrogen percentage and label. Winter rye follows a separate plan.
Does this schedule work for the high desert or northern AZ?+
No fixed month shift makes this low-desert guide accurate for higher elevations. Elevation, frost timing, exposure, and property microclimates change growth windows. Use these entries as reference points and confirm local timing before applying fertilizer.
Should I use a granular or liquid fertilizer?+
Neither form is always better. Choose a product labeled for the plant and site, then follow its rate and application method. Granular versus liquid depends on the product, plant, soil or growing medium, irrigation, and the need being addressed. Correct water stress before fertilizing.
University of Arizona references
Use the source guidance and each product label to turn a review window into a plant-specific decision.