What Is the Avocado Harvest Maturity Index and How Is It Measured?

Dr. Vijayalaxmi Kinhal

March 18, 2025 at 4:14 pm | Updated March 18, 2025 at 4:14 pm | 6 min read

Physical and chemical parameters and crop chronology are avocado harvest maturity indices.
Physical quality parameters, especially appearance, are commonly used worldwide.
Dry matter content measured by near-infrared spectroscopy-based devices has become the industry standard maturity index.
Sugar content is not a reliable avocado harvest maturity index.

Avocado fruits go through four stages of maturity and are harvested starting the third stage. Worldwide, different parameters are used to determine the proper maturity for harvest. Find out which parameter is helpful, such as the harvest maturity index for your area and cultivars and the established guideline values for each.

Unique Avocado Maturity Patterns

The flowering time in avocados is 2-12 weeks long, depending on the temperature. Also, unlike other fruits, avocados can be kept on the tree in the physiological mature but unripe stage, without ripening and decay for over 12 months. So, a single tree can have avocado fruits at varying maturity stages. Avocados’ “tree-store” property extends harvest time. The stress during harvesting triggers ripening processes, but predicting ripening time is difficult. How fast the fruits ripen postharvest will depend on temperature, sunlight, calcium levels, and maturity. Early-maturity stage fruits require more days to ripen, and mid and late-maturity avocados ripen faster.

Hence, classifying maturity and harvesting the avocados at the right time is crucial. Harvesting before avocados reach adequate maturity prevents the proper ripening required for consumer satisfaction. So, growers use the harvest maturity index to help fix the picking time.

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A harvest maturity index, a measurement, indicates a fruit is mature for harvest. Some standard harvest maturity indices used are fruiting chronology, physical quality parameters, and internal chemical properties.

Chronology Harvest Maturity Index

Chronology of crops, such as days after fruit set (DAFS), is used in India to guide harvest dates. Avocados are considered ready for harvest 140-150 DAFS.

Physical Harvest Maturity Indices

The standard physical harvest indices are color, shape, size, weight, and firmness.

Table 1: Optimum weight, size, soluble solids, color, and firmness harvest indices for avocados in Rwanda. (Credits: Maturity-indices-and-quality-local-avocados-not-hybrid)

Appearance

Avocados undergo several changes in appearance as they mature. Immature fruits are green, shiny, and smooth.

Avocado harvest begins in Rwanda when the skin is <50% rough. By the fourth stage, >50% of the skin is rough and develops yellow spots.
In India, the common variety Hass changes from green to purple-black. However, color change cannot be used alone as the harvest maturity index, as fruits can be unripe and hard when purple.
Australia uses dull skin color and a powdery appearance to indicate maturity for most cultivars. This parameter doesn’t work for thin-skinned fruits like the Bacon Variety. Destructive checks of seed coat color can also be used. Mature fruits have dry and dark seed coats, whereas immature fruits have pale whitish ones.

Stem method

Two methods are associated with stems in avocados. Ease of abscission of the small stem or cap, when the fruit is still green is a maturity indicator for Haas in India. In Australia, an enlarged, swollen, yellow stalk is used as a maturity indicator instead of a green stalk.

Fruit size, shape, and weight

Each cultivar has a known and characteristic size and shape at maturity, which can be used to determine harvest time.

In India, farmers use estimation based on previous seasons’ fruits to find the correct size and shape.
Rwandan farmers harvest local avocados that are not hybrids at an average length of 16 cm and 33 cm at circumference. Fruits with a weight of 1.5 kilos are suitable for harvest. See Table 1 for more details.
In Lebanon, the suitable size for cultivars Hass, Ettinger, Fuerte, Horshim, Pinkerton, Lambhass, and Reed at maturity varies based on location. Optimum fruit length ranges from 8.76 to 15 cm and width from 17.93 to 26.7 cm. See Table 2 for more details.
In India, a fruit length of 15.17 cm, a width of 8.43 cm, and a weight of 485.29 grams are suitable avocado harvest indices.

Specific gravity

In India, a specific gravity of 1.00 at 150 DFAS is also used as a harvest maturity index.

Firmness

Avocado firmness measured by a penetrometer using an 11 mm plunger expressed as FWS (kgF) is also suitable as a maturity index. The firmness differs based on variety and location, as shown in Table 2 for Lebanese avocados.

Table 2: Harvest indices used for avocados in Lebanon, Salameh et al. (2022). (Credits: https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.895964/full)

Chemical Harvest Maturity Indices

Maturity can also be determined by internal biochemistry tracked by chemical parameters such as dry matter (DM), oil content (OC), total soluble solids (TSS), and titratable acidity (TA).

Oil content

Avocados have a significant oil content in the fruit flesh. The oil content is crucial for achieving good eating quality and is used as a harvest maturity index. An oil content of 11-13%, corresponding to 22-24% of dry matter, is considered low as it indicates high water content and an insipid taste.

In Australia, oil content was the first parameter standardized in 1966, at 15% for Fuerte, Edranol, Rincon, and Zutano and 10% for other avocado varieties.
In Lebanon, oil content depends on cultivar and place, with a minimum of 8% in Reed avocados and 21.2% in Fuerte.

Since estimating oil content requires destructive sampling and complex and expensive laboratory analysis involving toxic solvents, it is being replaced by non-destructive measurements of DM since the two parameters are closely associated.

Dry matter

Non-destructive near-infrared (NIR) spectroscopy-based instruments are being used to measure DM content in avocados. The dry matter has become the most used chemical parameter as the harvest maturity index. International standards are at 19-25%, depending on the cultivar. Worldwide, Haas standards are 20.8%.

Country-wide standards for all avocado cultivars are:

23% for avocados in Chile

20.8% DM for Mexico
21.5% DM in Peru
25% Dm in South Africa
21% DM for all avocado cultivars in Australia.

Dry matter standards based on country and cultivar are as follows:

24% DM for Haas in New Zealand

23% for Haas in Australia and 21% DM for Shepard in Australia
17.7%-24.2% DM depending on variety in California
21% DM minimum for all avocados in Israel, with specific standards of 22.8% for Hass and 21% for Fuerte
23.5% DM for Haas in Columbia
27% DM for Lamb Haas in South Africa
9.7% DM for Reed and 28.5% DM for Fuerte

NIR spectrometers can also detect other quality parameters to calculate the avocado harvest maturity index.

Total soluble solids

Sugar accumulation doesn’t rise consistently with maturity in Lebanon and South Africa and is, therefore, not a reliable maturity index. However, in India, TSS is used as a harvest maturity index as it increases with maturity. A fruit with a TSS of 9.2°Brix is suitable for harvest.

Titratable acidity

Titrable acidity (TA) reduces with maturity as dry matter and oil content in avocados increase. It is, therefore, a crucial harvest maturity index.

In Lebanon, Lambhass avocado from Abbasiyeh can be harvested at 0.18% TA, while Ettinger and Pinkerton from Ansar and Nmeiriyeh need a TA of only 0.08%.
In India, the optimal TA is 0.60.

Near Infrared Spectroscopy

Physical quality parameters, especially appearance, are commonly used worldwide. NIR spectroscopy-based devices are more common for chemical harvest indices, especially DM content. Felix Instruments Applied Food Science has a quality NIR spectrometer, the F-751 Avocado Quality Meter, customized to measure dry matter for Haas avocados. It can measure a range of 14-40% dry matter. The device is small and portable, and it can be used in fields to provide easy-to-understand analysis in real-time, making avocado harvest more efficient.

Sources

Hunter, D. A., O’Donnell, K., Zhang, H., Erridge, Z. A., Napier, N. J., Pidakala, P., … & Woolf, A. B. (2024). On-tree ripening block of avocado fruit involves changes in ethylene sensitivity linked to gibberellin and auxin pathways. Postharvest Biology and Technology, 216, 113031.

Johnston, J., Requejo-Jackman, C., White, A., & Woolf, A. (2006). Avocado maturity: a review of harvest indices and the relationship with postharvest quality. Auckland, New Zealand, Horticulture and Food Research Institute of New Zealand Ltd (HortResearch), 1-38.

Kamble, V., & Narayana C.K. (n.d.). Floral Phenology and Maturity Indices in Avocad0. Retrieved from 07+Floral+Phenology+and+Maturity.pdf

Mccarthy, A., & McCauley, D.(2019, May 1). Avocado maturity testing using dry matter. Retrieved from https://www.agric.wa.gov.au/avocados/avocado-maturity-testing-using-dry-matter?page=0%2C1

Salameh, M., Nacouzi, D., Lahoud, G., Riachy, I., & El Kayal, W. (2022). Evaluation of Postharvest Maturity Indices of Commercial Avocado Varieties Grown at Various Elevations Along Lebanon’s Coast. Frontiers in Plant Science, 13, 895964.

UCDavis.Edu. (n.d.). Maturity indices and quality: local avocados (not hybrid). Retrieved from https://horticulture.ucdavis.edu/information/maturity-indices-and-quality-local-avocados-not-hybrid

UCDavis.Edu. (n.d.). Reducing postharvest losses in Rwanda Project. Retrieved from https://horticulture.ucdavis.edu/sites/g/files/dgvnsk1816/files/extension_material_files/Maturity-indices-and-quality-local-avocados-not-hybrid-190404.pdf

Woolf, A., Clark, C., Terander, E., Phetsomphou, V., Hofshi, R., Arpaia, M. L., … & White, A. (2003). Measuring avocado maturity; ongoing developments. The Orchidardist, 40-45.