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.

Days after emergence or planting	N (kg N/ha/day)			P (kg P/ha/day)			K (kg K/ha/day)
	Processing tomatoes	Greenhouse tomatoes	Fresh tomatoes	Processing tomatoes	Greenhouse tomatoes	Fresh tomatoes	Processing tomatoes	Greenhouse tomatoes	Fresh tomatoes
1-10	0.10	1.00	0.30	0.02	0.10	0.01	0.10	2.00	0.40
11-20	0.50	1.00	0.30	0.05	0.10	0.02	0.30	4.00	0.50
21-30	1.00	1.00	0.30	0.16	0.10	0.03	2.00	3.50	0.50
31-40	2.80	2.00	0.40	0.19	0.20	0.03	2.30	3.50	0.50
41-50	4.50	2.50	0.40	0.75	0.40	0.03	8.00	5.50	0.55
51-60	6.50	2.50	0.45	0.80	0.60	0.04	8.50	5.50	0.55
61-70	7.50	2.50	0.50	1.80	0.30	0.04	9.00	6.00	0.60
71-80	3.50	2.50	1.70	0.50	0.30	0.18	4.50	4.00	2.20
81-90	5.00	1.50	2.80	0.50	0.30	0.22	9.20	6.00	4.80
91-100	8.00	1.50	1.30	0.89	0.10	0.10	9.00	0.10	2.90
101-110	-	1.00	2.70	-	0.10	0.30	-	0.10	5.70
111-120	-	1.00	4.60	-	0.10	0.60	-	1.00	7.80
121-130	-	1.50	3.90	-	0.20	0.45	-	1.00	7.00
131-150	-	1.50	2.70	-	0.35	0.17	-	1.30	2.00
151-180	-	4.00	-	-	0.50	-	-	3.80	-
181-220	-	2.00	-	-	0.30	-	-	3.00	-
Total (kg/ha)	393	450	250	59	65	24	520	710	370

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

Typical Nutrient Removal Rates of Tomato

Growth environment	N	P2O5	K2O	MgO	CaO
			kg/mt yield
Greenhouse	2.6	1.9	4.8	0.6	2.9
Open field	3.0	2.2	5.5	0.8	3.8

Presented under license from AGMATIX data repository.

Tomato Deficiency and Toxicity Symptoms

Nutrient	Deficiency symptoms in tomato
Nitrogen (N)	General chlorosis of the older leaves. Slower growth and smaller plants. Fewer flowers and reduced yield.
Phosphoros (P)	Plants develop very slowly and are stunted, even at maturity. Leaves are a brighter color than normal, while the lower leaf surface is grey-green. Leaflets roll upwards under severe deficiency. Phosphorus deficiency can occur on calcareous and heavy soils, where P may be fixed.
Potassium (K)	Deficiency in potassium slows down plant growth; new leaves become tapered, and older ones exhibit yellowing at the edges, eventually turning brownish and necrotic. This yellowing typically progresses from the edges towards the center of the leaves. Occasionally, bright orange areas may appear. In many cases, a lack of fruit firmness is also attributable to potassium deficiency.
Magnesium (Mg)	Magnesium deficiency symptoms appear first on older leaves as general chlorosis while veins remain green. In severe cases, leaves display a scorched appearance due to interveinal necrosis. Magnesium deficiency may occur on sandy soils, and when K or Ca is applied at rates that are too high.
Calcium (Ca)	Calcium deficiency induces blossom-end rot (BER, collapsing of the distal part of the fruit). Deficiencies are severe in soils with pH below 5, salinity, heat, and cold weather.
Sulfur (S)	Sulfur deficiency symptoms are similar to N deficiency, but the chlorosis is uniform and general throughout the entire plant, including younger leaves. A typical reddish color develops on leaves’ petioles and veins.
Iron (Fe)	Iron-deficient leaves show strong chlorosis at the base of the leaves with some green netting. The most common symptom of iron deficiency starts out as an interveinal chlorosis of the youngest leaves, evolves into an overall chlorosis, and ends as a totally bleached leaf. Because iron has a low mobility, iron deficiency symptoms appear first on the youngest leaves. Iron deficiency is strongly associated with calcareous soils, anaerobic conditions, and it is often induced by an excess of heavy metals.
Manganese (Mn)	At the earlier stages, light chlorosis appears on the young leaves. In more severe cases, mature leaves show netted veins, and then the leaves develop brown-grey necrosis along the veins. It occurs on high-pH and calcareous soils, or excessively limed soils.
Zinc (Zn)	Zinc deficiency causes stunting of tomato plants and upward rolling of young leaves, grey-brown to bronze areas may develop on the leaves. It appears on alkaline soils, or when high P is applied.
Copper (Cu)	Curled leaves, with petioles bent downward. May be expressed as a light overall chlorosis along with permanent loss of turgor in the young leaves, recently matured leaves show netted, green veining with areas bleaching to a whitish grey.
Boron (B)	Boron deficiency symptoms generally appear firstly on young leaves, as a lighter color. Severe deficiency shows on older leaves as interveinal chlorosis, which develops to a deep yellow-orange hue, with brittle leaves that may show rolled-up edges and a corky stem-end of the tomato fruit.
Molybdenum (Mo)	An early symptom of molybdenum deficiency is overall chlorosis, very similar to nitrogen deficiency, but without the reddish coloration on the undersides of the leaves. Leaves exhibit upward cupping and mottled spots, developing into large interveinal chlorotic areas occurring under severe deficiency.
Chloride (Cl)	Abnormally shaped leaves, with distinct interveinal chlorosis. Chlorosis occurs on smooth flat depressions in the interveinal area of the leaf blade. In more advanced cases a characteristic bronzing on the upper side of mature leaves appears. Chloride deficiency can be found in highly leached inland areas.

Adapted from IPI Crop Bulletin 13 (ipipotash.org)

Nutrient	Toxicity symptoms in vegetables
Manganese	May occur as part of "soil acidity complex" if the pH falls below 5.0. Dark brown/black spots appear first in the cotyledons, with similar symptoms observed in the leaves, progressively from the oldest leaf. Brassica crops show inward rolling of leaf edges, interveinal chlorosis, and necrotic spotting. Lettuce’s older leaf edges become golden yellow. Mn concentrations above 500 mg/kg in the affected leaf margins would indicate the problem.
Aluminium	Whereas brassicas suffer Mn toxicity on acid soils, certain crops, notably sugar beet and celery are resistant to it, but instead suffer from aluminum toxicity to which brassicas are tolerant. Symptoms are mainly on the roots and include thickening, clubbing, and blackening of the roots, and inhibition of root elongation, although celery shows petiole collapse and necrosis of the growing point.
Boron	This occurs mainly as a result of over-dosing when attempting to correct B deficiency (which is very easily done) and when irrigation water contains more than about 0.75 mg B/L. Lettuce is rather susceptible: older leaves show pale margins.
Ammonia	Wilting, interveinal and marginal necrosis (scorch) of leaves; brown roots. Tissue NH4+ concentration is diagnostic but the critical value is genotype dependent. May occur in compost-grown plants following steam sterilization, or storage of the compost.
Chloride	May occur in saline conditions. Causes marginal leaf scorch similar to K deficiency.

Adapted from IPI Crop Bulletin 13 (ipipotash.org)

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).

Fertilizer Products for Tomato Production

Product type	Field grown tomatoes			Greenhouse tomatoes
	Very much used	Moderately used	Not relevant	Very much used	Moderately used	Not relevant
Potash-based fertilizers	+
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	+			+