Advice for growing Avocado (Persea Americana Mill.)
Everything you need to know about avocado fertilization, best practice, field trials, and more.
Advice for growing Avocado (Persea Americana Mill.)
The avocado, Persea americana Mill., belongs to the family Lauraceae. It has developed three horticultural races: the Mexican race, P. americana var. Drymifolia, adapted to the tropical highlands; the Guatemalan race, P. americana var. Guatemalensis, adapted to medium elevations in the tropics, and the West Indian race, P. americana var. americana, adapted to the lowland humid tropics. Present commercial avocado production is based on various selections of these three races and of hybrids among them. For example, the most common Hass cultivar, is from the Mexican X Guatemalan races.
The avocado is a subtropical evergreen tree which is never dormant, although its activity is reduced during the winter as compared with spring and summer. Temperatures at, or somewhat below freezing point harm the fruit, buds and foliage of young trees. Temperature below freezing for only a few hours, can cause serious injury to mature trees. Of the three horticultural races, the West
Indian is the most susceptible to low temperatures while the Mexican race is the coldest hardy. It is preferable to plant trees in frost-free areas, such as on slopes with good air drainage. Most cultivars of avocado do not ripe or undergo climacteric change if the fruit remains attached to the plant.
Avocado has been used as an edible fruit for at least 9,000 years in, and near its centre of origin in Mexico (Tehuacán Valley) and Central America, where horticultural activities for improvement of avocado were exercised. The earliest known written account of the avocado in Europe was in 1519. Expansion to other continents started in the 17th century. Avocado has reached Southern Spain in 1601, to Jamaica in 1650 and throughout the Indonesian archipelago, by Spanish merchants, since the 17th century. The tree has been grown in Australia since mid-18th century, Zanzibar 1892, Florida 1833 California 1856. In the 20th century it reached Taiwan (1918), Israel (1924) and China Guangdong in 1925.
Avocado trees can be planted on a great variety of soils. However, to ensure a suitable soil type the following conditions should be considered:
- As avocado roots are particularly sensitive to poor aeration, it is not recommended to plant on excessively heavy, compact soils, with poor permeability. Planting on ridges to allow draining of excess water may enable planting in such soils.
- Avocado trees show considerable variation in their tolerance to lime (and soil pH), in conjunction with the size of lime particles. As a general guideline, the maximum total soil lime content for the Guatemalan rootstock ( Nabal) is estimated at 4—5%, for the Mexican rootstock at 20—25%, and some West Indian stocks can withstand even above 40%.
- Recommended soil pH for avocado is 5.5 (in water), but if soil Mn is in excess, aim for pH 6.5. Low (acid) pH suppresses Phytophthora root rot.
Avocado is sensitive to water salinity (when irrigated). Irrigation water containing above 120—150 ppm Cl generally causes leaf burn, often in severe form, along margins and tips of blades on trees grafted on Mexican rootstocks. However, no signs of damage are found on trees grafted on some West Indian stocks even when the water contains 230—300 ppm Cl. It should not be overlooked that salts which accumulate in the soil during the irrigation season can be partially leached with increased irrigation water allocations (+25—35%), provided good drainage conditions prevail. Mexican rootstocks can be used with Cl concentration of up to 5 meq/L. The salt tolerance of selected West Indian rootstocks seems to be higher than 10 meq/L.
Avocado is one of more than 105 crops that receive yield benefits from insects (inc bees) pollination, a process that represents achieving approximately 35% of total agricultural production. Avocado is a mass flowering species, however natural fruit set rates in orchards are extremely low (around 0.3%). While typically a low fruit set is expected in mass flowering species, in avocado, even with hand pollination, only around 5% fruit set is achieved.
Global production
Global avocado is grown on an area close to 1 million ha with only three countries possessing 50% of the area (Mexico, Colombia and Peru). Global production is cerca 10 million mt fresh fruit, and global average productivity remains steady at 10 mt/ha for many years (1960-2022). The fast growth of the avocado market is explained by vast additional planting since 2007. The productivity of avocado remains a major obstacle for many even advanced orchards.
Crop usage
Avocado is a farm-to-market fruit and requires no special storage or packing. As a fresh fruit, it is a nutrient-rich food that is a good source of several vitamins, minerals, and plant compounds. Avocado also contains a high amount of protein (2.3%) as compared to other fruits (~0.8%). In addition, avocados are a good source of fiber and contain more fat (mostly unsaturated) than carbohydrates but contain no cholesterol. It is considered as one of the highest-fat plant foods. Avocado is frequently named ‘Superfood’, ‘Ultimate superfood’
In terms of human health, avocado consumers tend to have higher HDL-cholesterol, lower risk of metabolic syndrome, and lower weight, BMI, and waist circumference than those with no consumption. One avocado fruit (~136g) has nutrient and phytochemical profiles like 42.5g of tree nuts (almonds, pistachios or walnuts), which have qualified heart health claims
A whole medium size avocado contains about 240 calories, 13 grams carbohydrate, 3 grams protein, 22 grams fat (15 grams monounsaturated, 4 grams polyunsaturated, 3 grams saturated), 10 grams fiber, and 11 milligrams sodium. Along with their low sodium levels, avocados contain no cholesterol. Avocados have the highest energy value (245 cal/100 gr) of any fruit besides being a reservoir of vitamins (A as carotene, ascorbic acid, niacin, riboflavin and thiamine) and minerals. Avocado is rich in potassium: a single avocado contains 975 milligrams of potassium, compared to 487 milligrams in a banana. Avocado is also very rich in magnesium
Composition of avocado fruit (of 1 fruit, ~200 g) and share of the daily recommended amount for adults. Based on 86% California and 14% Florida varieties; others.
Source: USDA FoodData Central (usda.gov) and others.
Element | Conc. | Share of Daily Value (DV) | Conc. | Share of Daily value (DV) | |
---|---|---|---|---|---|
Water | 147 g | Protein | 4.02 g | ||
Energy | 322 kcal | Carbohydrate, by difference | 17.1 g | ||
Energy | 1350 kj | Fiber, total dietary | 13.5 g | ||
Total lipid (fat) | 29.5 g | Total Sugars | 1.33 g | ||
Ash | 3.18 g | Sucrose | 0.121 g | ||
Calcium, Ca | 24.1 mg | 2.4% | Glucose | 0.744 g | |
Iron, Fe | 1.1 mg | 5% | Fructose | 0.241 g | |
Magnesium, Mg | 58.3 mg | 14% | Lactose | 0 g | |
Phosphorus, P | 105 mg | 15% | Maltose | 0 g | |
Potassium, K | 975 mg | 21% | Galactose | 0.21 g | |
Sodium, Na | 14.1 mg | Starch | 0.221 g | ||
Zinc, Zn | 1.29 mg | 13% | Vitamin C, total ascorbic acid | 20.1 mg | 22% |
Copper, Cu | 0.382 mg | 42% | Thiamin | 0.135 mg | 12% |
Manganese, Mn | 0.285 mg | 12% | Riboflavin (B2) | 0.261 mg | 20% |
Selenium, Se | 0.84 µg | 1.5% | Niacin | 3.5 mg | 22% |
Fluoride, F | 14.1 µg | Pantothenic acid (B5) | 2.79 mg | 56% | |
Folate | 163 | 41% | Vitamin B6 | 0.517 mg | 30% |
Lycopene | 0 µg | Vitamin E | 4.16 mg | 28% | |
Cholesterol | 0 mg | Vitamin K | 42.2 µg | 35% | |
Fatty acids, total trans | 0 g | Carotene, beta | 62 µg | ||
Fatty acids, total polyunsaturated | 1.82 g | Carotene, alpha | 24 µg | ||
Fatty acids, total monounsaturated | 9.8 g | Vitamin B-6 | 0.257 mg | ||
Fatty acids, total saturated | 2.13 | Vitamin A, IU | 146 IU |
Nutrient’s role
The avocado tree is known for its superficial root system (80% of the feeder roots are in the top 15cm), a fact to be considered in agricultural practices such as irrigation, cultivation and fertilization. The demand for mineral nutrition is higher in places where the avocado is grown on shallow, light or rocky soils. Moreover, healthy and dense foliage is required to achieve high yields, and leaf nutritional status is commonly used for fertilization management decisions in the avocado industry.
Nitrogen (N)
The demand for N is high as fruit is a major sink for N and the protein content found is far above other commercially produced fruit (2.3%), including deciduous, subtropical or tropical tree crops (typically just 0.8% protein). N fertilizer applied to avocado trees is predominantly used to synthesize protein.
Nitrogen is considered to have a great influence on the growth of the avocado tree and is therefore commonly used. It is advisable to fertilize each cultivar selectively. Cultivars distinguished by high fertility requires higher N applications prior to an «on» year, and lower amounts prior to an «off» year.
Due to the high need for nitrogen during vegetative growth periods, nitrogen fertilization is also recommended during few months before flowering (~25% of the total yearly amount). A +10% yield increase can be expected.
Phosphorus (P)
Phosphorus is essential for the production of ATP (adenosine triphosphate), which is vital for energy transfer within the plant. This energy is necessary for various physiological processes, including growth and development.
Adequate phosphorus levels promote healthy root development, which is crucial for nutrient and water uptake. Strong root systems help the avocado tree to establish itself and thrive.
Phosphorus is also important for flower formation and fruit set. It helps in the development of flowers and ensures that the tree can produce a good yield of avocados.
Potassium
Potassium is required in high quantities to support the strong vegetative growth and that of fruit requirement. Due to its sensitivity to chloride, common fertilizer sources for avocado include potassium nitrate (KNO3), potassium sulfate (K2SO4) and potassium thiosulfate (KTS; K2S2O3).
Potassium is essential for the uptake and transport of other nutrients within the avocado plant. It helps in the movement of water, nutrients, and carbohydrates.
Adequate potassium inputs contribute to better fruit quality, including size, taste, and shelf life. It helps in the development of strong cell walls, which is important for the firmness and storage life of avocados.
Potassium enhances the plant’s resistance to diseases and pests.
Magnesium
Magnesium is a central component of the chlorophyll molecule, which is essential for photosynthesis. Without adequate magnesium, the plant’s ability to capture sunlight and convert it into energy is compromised. Mg also acts as an activator for many plant enzymes that are important for normal growth and development.
Magnesium helps in balancing other nutrients within the plant. It aids in the uptake and transport of phosphorus, which is vital for root development and flower formation. Adequate magnesium levels contribute to better fruit quality, including size and taste.
P is also involved in the formation of sugar phosphates (intermediary esters in the metabolism of sugars and are usually found in low concentrations in mature fruits) which are important for storing and transferring energy within the plant.
Calcium
High fruit calcium and fruit quality are linked, and calcium is deposited in the fruit at an early stage (the first 6 to 8 weeks after fruit set). However, when soil calcium is high (65 to 70% of the base saturation) there is no need to add Ca fertilizer.
Zinc
Zinc is considered an important element to the avocado tree. Zn is involved in diverse metabolic plant functions. high Zn concentration in the productive organs suggest Zn transport through the phloem (while in many plants is via the xylem).
Boron
B transport in many plants is via the xylem system, but in avocado tree it has been reported to be through the phloem.
Avocado Nutrient requirements and fertilization
Fruits rather than leaves are the main sink in avocado trees. For example, removal of N, P and K in fruit (cv. Hass, at yield of 30 mt/ha) during 150 days (from 29 May, Northern hemisphere) is 125, 23 and 250 kg/ha, respectively. Annual quantities of N, P2O5 and K2O required for attaining high quality avocado yield are in the order of 250–300, 180–270 and 600-720 kg/ha, respectively (Silber et al., 2018). Moreover, N, P and K are taken by fruit in a relatively steady rate during all these 150 days of growth.
Typical nutrient removal rates of avocado fruit
N | P2O5 | K2O | MgO | CaO |
---|---|---|---|---|
kg/mt avocado | ||||
14.7 | 4.0 | 29.7 | 3.6 | 12.4 |
Adequate levels of nutrients in avocado leaves (concentration in DM)
Avocado | cv. Hass | cv. Fuerte | cv. Pinkerton | Mexican stock | |
---|---|---|---|---|---|
N (%) | 2.25-2.90 | >2.0 | 1.6-2.0 | >2.3 | |
P (%) | 0.10-0.15 | ||||
K (%) | 0.7-0.9 | ||||
Ca (%) | 1.8-2.0 | ||||
Mg (%) | 0.6-0.9 | ||||
S (%) | 0.45-0.53 | ||||
Na (%) | 0.25 | ||||
Cl (%) | <2.0 | ||||
Zn (ppm) | 50-80 | ||||
Mn (ppm) | 110-145 | ||||
Fe (ppm) | 55-80 | ||||
Cu (ppm) | 4-7 | ||||
B (ppm) | 38-60 |
Deficiency, excess and toxicity symptoms
Nitrogen | Deficiency of N leads to pale green leaves and fruit, small leaves and fruit, low yields, reduced tree vigor, and when acute, chlorosis (yellowing) of leaf veins. restricted growth, pale, , and early leaf shedding. In cases of acute lack of N, the veins turn yellow. nitrogen deficient trees were found to be more susceptible to frost damage. In cv. Hass, reddish small fruit, sensitive to chill conditions. Excessive N results in lower postharvest quality and advanced ripening. In cv. Hass, internal grey tissue and increased rot. |
Phosphorus | Deficiency of P causes decrease of vegetative growth, small round leaves, early leaf shedding, and branch dieback. Leaves are brownish green in colour and burnt. Excess amounts of P are likely to cause Zn deficiency symptoms |
Potassium | Deficiency of K results in small and narrow leaves. Older leaves show the first signs of potassium deficiency. In autumn, brownish-red necrotic spots began to appear on older leaves, subsequently, the spots spread over the whole leaf blade between the large veins. On severely deficient trees, the twigs were very thin, and some dieback occurred. |
Calcium | Deficiency of Ca results in scorched leaf tips and small sized leaves. Deficiency is affecting young leaves first. Symptoms are sometimes similar to those of Phytophthora cinnamomi. |
Magnesium | Deficiency of Mg results in intra-veinal chlorosis in mature leaves which produces scorch of the leaf margins. Older leaves are first to show magnesium deficiency. |
Sulphur | Sulphur deficiency symptoms are quite like those of nitrogen. Young leaves are more sensitive than older ones. Typical symptoms include the yellow colour and smaller leaf size. Excessive concentrations of sulfur in avocado leaves leads to loss of green color and severe marginal leaf burn. |
Zinc | Deficiency of Zn results reduction in leaf size and development of “mottleleaf”, shortened internode length on the branches, reduced fruit size, and in cv. Hass, cv. Ettinger and cv. Fuerte avocado, the production of round misshapen fruit. |
Iron | Iron deficiency results in inter-veinal yellowish colour and narrow dark-green strips along the veins of the leaves. With progressive deficiency, leaves of the summer flush become smaller, more delicate and, while young, have a pale yellow to white color. Later, severely chlorotic leaves show scorch symptoms at their tips and along margins and in extreme cases are shed. Trees on West Indian stocks are more tolerant of high soil pH, salinity & iron deficiency. |
Manganese deficiency | Manganese deficiency results in intra veinal chlorosis, similar to that occurring in cases of Zn and Mg deficiency. |
Boron deficiency | Boron deficiency results in short and thick branches and scorched leaf blade margins, followed by early leaf shedding. At a later stage, internodes become very short and the leaves scale-like. Mexican rootstocks are less efficient at boron uptake. |
Chloride toxicity | Chloride toxicity results in leaf burn — tips and margins, aggravated during the summer and autumn to the point of leaf shedding. |
Sodium toxicity | Sodium toxicity results in interveinal necrotic spots; leaf buds are affected and branches - young and mature - dry up to the point of complete degeneration. |
Source: IPI Crop Bulletin 6. Fertilizing for high yield: Avocado. Lahav and Kadman, 1980. International Potash Institute, Zug, Switzerland.
Product type
Product type | Commercial plantations |
---|---|
Potash-based fertilizers | Exc. Cl based. |
Phosphate-based fertilizers | + |
Complex & blended granular fertilizers | + |
Polysulphate-based Fertilizers | + |
Water soluble fertilizers (WSF) | + |
Liquid fertilizers | + |
Controlled release fertilizers (CRF) | + |
Biostimulants | + |
Organic fertilizers | + |
Micronutrients package | + |
Wetting agents | + |
Application method | |
Foliar | + |
Fertigation | + |
Row application | + |
Planting holes | + |
Bulk blending | + |
Broadcast | + |
NPK granulation | + |
Technologies | |
E-Max | + |
Poly-S | + |
Resin | + |
V-Factor | + |
M-77 | + |
F3 SurfActive | + |
X3-Active | + |
PeKacid | + |
DPI | + |
eqo.x | + |
Literature & Guides
- Avocado fertilization: Matching the periodic demand for nutrients. Silber et al., 2018. Scientia Horticulturae 241, 231-240.
- Avocado mineral nutrition the water-nutrients relationship. Lahav and Aycicegi-Lowengart, 2013. V Congreso Mondial del aguacate, Granada Malaga, Spain. Actes 1, 349–
- Decision support tools for avocado fertilization & salinity management: Preview to the final project report. Crowley et al., 2015. California AvoTech, From the Grove. pdf (ucr.edu)
- Foliar application of boron to improve ‘Hass’ avocado productivity. Lazare et al., 2022. Acta Hortic. 1333. ISHS. DOI 10.17660/ActaHortic.2022.1333.42 Proc. IX International Symposium on Mineral Nutrition of Fruit Crops Eds.: A. Dag et al.
- Hass avocado composition and potential health effects. Dreher and Davenport, 2013. Critical Reviews in Food Science and Nutrition, 53:7, 738-750, DOI: 10.1080/10408398.2011.556759.
- Hass avocado nutrition research In California. Lovatt, C. Hass Avocado Nutrition Research In California (avocadosource.com)
- IPI Crop Bulletin 6. Fertilizing for high yield: Avocado. Lahav and Kadman, 1980. International Potash Institute (IPI), Zug, Switzerland.
- Persea americana (avocado): bringing ancient flowers to fruit in the genomics era. Chanderbali et al., 2008. BioEssays 30:386–396. DOI 10.1002/bies.20721.
- Primary metabolism in avocado fruit. Pedreschi et al., 2019. Frontiers in Plant Science. Volume 10 – 2019 | https://doi.org/10.3389/fpls.2019.00795.
- Patterns of nutrient accumulation in ‘Hass’ avocado fruit. Rosecrance et al., 2012. Better Crops 2012-1 p.12-13.pdf (ipni.net)
- Response of avocado cv. Hass to winter fertilization: a summary of four years experiment (in Hebrew). Erel et al., 2024. Alon Hanotea, May, p 28-30.
- The forgotten fruit: A case for consuming avocado within the traditional mediterranean diet. Ford and Liu, 2020. Frontiers in Nutrition. 7:78. doi: 10.3389/fnut.2020.00078.
- Zinc fertilization of avocado Trees. Crowley and Smith. 1996. HORTSCIENCE 31(2):224–229.
Field experiments, Agronomic Reports and Related Literature
- Avocado industry – statistics & facts | Statista
- Avocado fertilization to optimize productivity in a subtropical environment – Center for Fertilization and Plant Nutrition (cfpn.center)
- Avocado production, 2022 (ourworldindata.org)
- Avocados – The Nutrition Source (harvard.edu)
- Avocado Tree Fertilization Basics | California Avocado Commission (californiaavocadogrowers.com)
- Boron substantially increases avocado yield – Center for Fertilization and Plant Nutrition (cfpn.center)
- CDFA – FREP – CA Fertilization Guidelines – Avocado
- Exploring Avocado Farming in Spain: A Fruitful Visit. Exploring Avocado Farming in Spain: A Fruitful Visit | ICL (icl-growingsolutions.com)
- Avocado or Avocada? Celebrating 100 years of Avocado crop in Israel. Magen, 2024 (in Hebrew). Kenes-Media.