Crop Program · Avocados

Avocados don’t feed on a calendar — they feed on their own bearing cycle.

Hass avocado is alternate-bearing: a heavy “on” crop year and a lighter “off” year pull nitrogen very differently. Because that cycle shifts demand from grove to grove and year to year, we build every avocado program with you rather than publish one fixed rate.

The science

Nitrogen demand tracks the tree, not the season.

University and CDFA FREP research on ‘Hass’ avocado shows very little nitrogen uptake during the winter dormant period. Uptake climbs sharply from March through May, when the spring flush, bloom, and fruit set of the new crop all happen at once — and in “on” crop-load years, a second demand window opens from July through October as that heavy crop sizes up. Research led by UC Riverside’s Carol Lovatt found that properly timing nitrogen to these specific phenological stages, rather than spreading it evenly across the year, measurably increased both total yield and the share of commercially valuable, large-size fruit.

125 lb

N/acre/year — widely-used research rate for mature bearing groves

5–6

split applications timed to key phenological stages

Mar–May

peak uptake window: spring flush, bloom & fruit set

Why split timing matters more than total rate. Lovatt’s research found that doubling the nitrogen dose at specific stages — particularly April or November — significantly increased four-year cumulative yield, while under-supplying nitrogen during the critical summer growth window (July–August) reduced it. In other words, avocado programs are won or lost more on timing than on total pounds applied — which is exactly the kind of precision a spoon-fed, well-timed program is built for.

Demand context

How much nitrogen avocados need.

These CDFA FREP and UC research ranges are planning context, not a program. Actual demand depends heavily on tree age, crop load, and your irrigation water’s own nitrate content — which is why every COFI avocado program is built to your grove.

Grove stage	Typical annual N range
Young, non-bearing (years 1–3)	Building gradually as canopy establishes
Mature, bearing — typical program	~125 lb N/acre/year, split across 5–6 applications
Mature, bearing — broader guideline range	~100–200 lb N/acre/year, by variety, soil & irrigation water N

These ranges shift with the factors below — which is why avocados resist a one-size-fits-all program:

Alternate bearing (on/off year)Tree age & canopy sizeCrop load / yield goalIrrigation water nitrate contentSoil type & leaching riskVariety (Hass vs. Fuerte, Bacon, Zutano)Mulch & soil organic matter

An organic-system program. These ranges are total demand, not a fertilizer rate. In an organic grove, part of that nitrogen comes from soil organic matter, mulch breakdown, and biological activity — a dry Phyta-Grow® and liquid Phytamin® program supplies the well-timed, plant-available portion on top of that biological base. Because avocado roots are notably salt- and chloride-sensitive, matching rate and timing to your grove — rather than over-applying — also protects root health.

Let’s build your avocado program.

Because avocado nitrogen demand shifts with bearing cycle, tree age, and irrigation water, we don’t publish a single rate. A COFI agronomist will build a program around dry Phyta-Grow® and liquid Phytamin®, timed to your grove’s own phenology and crop load.

Talk to a COFI agronomist

Sources

Seasonal nitrogen uptake and partitioning: CDFA FREP California Crop Fertilization Guidelines, Avocado Nitrogen Uptake and Partitioning (cdfa.ca.gov/is/ffldrs/frep). Timing research: Lovatt, C.J., “Properly Timed Soil-Applied Nitrogen Fertilizer Increases Yield and Fruit Size of ‘Hass’ Avocado,” HortTechnology. Rate guidelines and crop N removal: UC Davis Nutrient Management (geisseler.ucdavis.edu), Avocado. Product analysis: Phyta-Grow® and Phytamin® CDFA-registered labels, California Organic Fertilizers.

This page is planning context, not a prescription. Avocado nitrogen rate and timing must be set for each grove using its bearing cycle, tree age, crop load, soil type, and irrigation water nitrate content. Finalize your program with a COFI agronomist and your PCA or Certified Crop Adviser.

DOWNLOAD AVOCADO CROP PROGRAM PDF

THE ORGANIC AGRONOMIST

Can Available Nitrogen Reduce Alternate Bearing in Avocados?

Explore how crop load, nitrogen timing, return bloom, and plant-available nitrogen interact—and where the evidence for natural ammonia still stops.

Read the Avocado Article

Flow chart titled 'Where Available Nitrogen May Influence Avocado Alternate Bearing' illustrating factors affecting avocado crop cycles, including heavy 'on' crop, high demand, less return growth, reduced return bloom, light 'off' crop, more vegetative growth, return flowering, and research support points.