Growing Tomato
Crop Nutrition Advice

Tomato (Solanum lycopersicum) belongs to the Solanaceae family and is the second most important vegetable crop after potato. World production (2022) is about 186 million tons of fresh fruit from 5 million ha (FAOSTAT, 2022). China accounts for 1/3 of global production (68 million mt), followed by India and the U.S. (20 and 10 million mt, respectively).

Tomato crops grow rapidly with a growing period of 90 to 150 days. It is a daylength neutral plant and hence can be grown in many regions. The optimum mean daily temperature for growth is 21 to 24ºC with night temperatures between 10 and 20ºC. Dry climates are preferred for tomato production. Tomato is classified as a climacteric fruit, and dramatic metabolic changes occur during its fruit development.

Tomato can be grown on a wide range of soils, but a well-drained, light loam soil with a pH of 5 to 7 is preferred. Waterlogging increases the incidence of diseases such as bacterial wilt. Tomato is also grown as a greenhouse crop using a wide range of soil-less cultures.

The crop is relatively insensitive to soil salinity, and tomato yield will only be reduced at high EC levels. Yield decrease is 0% at ECe 2.5 dS/m, 10% at 3.5, 25% at 5.0, 50% at 7.6 and 100% at ECe > 12.5 dS/m. Tomato crops are most sensitive to salinity during germination and early plant development, and necessary leaching of salts is therefore frequently practiced during pre-irrigation or by over-watering during the initial irrigation application. Tomato is ‘chloride neutral’ but prefers sulfate as the accompanying ion for potassium.

Tomatoes play a significant role in human nutrition due to their diverse health benefits and nutrient content. The fruit is a good source of vitamins C and A, potassium, lycopene, and beta-carotene.

What are the most Common Uses of Tomatoes?

Of the annual 190 million mt tomato crop, approx. 50% is processed into various sauces, pastes, canned tomatoes, juice, and ketchup. Different qualities required for the processing industry imply the use of different varieties and agronomic practices. Brix (dissolved solids in liquid) level is a crucial factor that impacts the quality and taste of tomato-based products.

What are the most Important Nutrients for Tomatoes?

Nitrogen (N) plays a crucial role in tomato production, contributing significantly to crop growth and development. It is a key component of enzymes, vitamins, chlorophyll, and other cell constituents. Adequate nitrogen levels in the plant are necessary for high tomato crop yields. Tomato crops require an optimal balance between ammonium and nitrate forms. Nitrogen affects all the crop’s growth stages: it promotes strong early growth, ensures continued growth, supports flower development, maximizes flower numbers, and maintains fruit fill.

Phosphorus (P) is a vital nutrient for tomato production, influencing both yield and quality. Phosphorus is a component of nucleic acids (DNA and RNA), and it plays a direct role in energy transfer within the plant. These processes impact overall yield and crop quality. Phosphorus contributes to the quality of the fruit by increasing Total Soluble Solids (TSS), or Brix.

Potassium (K) has a major effect on tomato yield and quality, due to its role in maintaining ionic balance and water status in the plant. It ensures proper water movement, which is essential for nutrient uptake and overall plant health. Potassium is also involved in the production and transport of sugars, in energy metabolism and it contributes to the growth and development of fruits. Potassium plays a role in protein synthesis, enzyme activation, and pigment synthesis, notably lycopene. Potassium influences fruit ripening and determines the level of sugars in the fruit. An inadequate supply of potassium may result in uneven ripening, affecting fruit quality, and may lead to blotchy ripening and color defects (such as internal white tissues or yellow shoulder). Higher potassium levels may increase the acidity of tomato juice.

Magnesium (Mg) affects various critical physiological and biochemical processes in higher plants, and its deficiency impedes plant growth and development. Magnesium is essential for chlorophyll synthesis and participates in energy transfer processes in the plant. It ensures uniform ripening of well-formed tomato fruit and affects fruit shape. Magnesium is necessary for protein synthesis and enzyme activation. During the crop’s growth, magnesium improves flowering and crop production and is essential for high-quality fruit production.

Calcium (Ca) plays a pivotal role in the nutrition of tomato plants, influencing various aspects of growth, fruit quality, and overall productivity. Calcium is a key component of cells, contributing to the structure of cell walls and stabilizing cell membranes. It enhances pollen germination and is involved in the regulation of various enzyme systems. Calcium has a specific influence on tomato fruit quality, especially in preventing blossom-end rot (BER) and improving the firmness of the fruit.

Nutrient Interactions

Nutrient interactions in tomatoes, as with many higher plants, are extremely important. For example, the antagonistic effect of K on Mg is stronger than that of Mg on K in root absorption and transport within plants, indicating, that the balanced use of K and Mg fertilizers is necessary to sustain high plant-available Mg while alleviating K-induced Mg deficiency. This is particularly important in tomatoes which have a high K demand, and even more important in soils rich in potassium (Xie et al., 2021). Excess application of ammonium (NH₄) negatively impacts plant development and results in calcium deficiency (Bonomelli et al., 2021).

Nutrient Requirements and Fertilization

Daily nitrogen (N), phosphorous (P), and potassium (K) consumption rate of tomato under drip fertigation as a function of time after emergence or planting.

Adapted from IPI Crop Bulletin 13 (ipipotash.org) and https://vikaspedia.in

Typical Nutrient Removal Rates of Tomato

Tomato Deficiency and Toxicity Symptoms

Adapted from IPI Crop Bulletin 13 (ipipotash.org)

Adapted from IPI Crop Bulletin 13 (ipipotash.org)

Fertilizer Products for Tomato Production

Literature

1. Ammonium excess leads to Ca restrictions, morphological changes, and nutritional imbalances in tomato plants, which can be monitored by the N/Ca Ratio. Agronomy, 11, 1437. doi.org/10.3390/agronomy11071437
2. FAO Land & Water: Tomato, Food and Agriculture Organization of the United Nations (fao.org)
3. IPI Crop Bulletin 13 (ipipotash.org)
4. Synergistic and antagonistic interactions between potassium and Magnesium in higher plants. Xie et al., 2021. doi.org/10.1016/j.cj.2020.10.005.
5. Tomato Fruit Development and Metabolism. Front. Plant Sci., 29 November 2019. (frontiersin.org)
6. Tomato responses to salinity stress: From morphological traits to genetic changes. Roșca et al., 2023. Front. Plant Sci. 14:1118383. doi: doi.org/10.3389/fpls.2023.1118383

Field Experiments, Agronomic Reports, and Related Literature

1. Increases in Yield and Vitamin C Levels of Tomato Grown on K₂HPO₄-enriched Zeolite in an Inert-Sand Substrate. Bernardi, et al., March 2013. e-ifc 33 (ipipotash.org).
2. On Farm Evaluation of Polyhalite – A Promising Fertilizer for Nutrient Management in Greenhouse Tomatoes. Sacks, et al, November 2019. (ipipotash.org)
3. Polyhalite – A Multi-Nutrient Fertilizer Preventing Ca and Mg Deficiencies in Greenhouse Tomatoes under Desalinized Irrigation Water. Sacks., et al, December 2017. e-ifc 51 (ipipotash.org).
4. Success using Polysulphate Fertilizer on Tomato Crop. Increasing Tomato Crop Profit with Polysulphate | ICL (icl-growingsolutions.com)
5. Yield and fruit quality of tomato as affected by rates and ratios of K and Ca in water culture. IPI International Symposium on Fertigation; Optimizing the utilization of water and nutrients; Beijing, September 20-24, 2005 (ipipotash.org).