Growing Tomato
Crop Nutrition Advice
Everything you need to know about tomato fertilization, best practice, suitable products, field trials and more.
Advice for growing Tomato (Solanum lycopersicum)
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Tomatoes perform better in soil with a pH between 5.5 and 6.5.
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In pH values above 7.5, deficiencies of Cu, Fe, Mn, P, and Zn are likely to appear. In soil with a pH below 5.5, tomatoes are prone to P, Mo, and Ca deficiencies.
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Tomatoes perform best at temperatures of 18-27ºC.
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Flower formation could be affected under temperatures above 27°C. below 22 °C
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Temperatures above 34ºC for long periods cause problems such as physiological imbalances, etc…
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Field-grown tomatoes water requirement are 4,000-6,000 m³/ha, while protected crop consumes up to 10,000 m³/ha. Water requirement is high from transplanting to fruit setting. It peaks during early fruit development and is much lower during ripening. Actually, a minor water stress during ripening stage improves fruit firmness, sugar content, taste, and shelf-life, but may result in reduced fruit size.
Nutrient requirements
Estimated nutrient uptake (kg/t):
N | P | K | Ca | Mg | S | |
---|---|---|---|---|---|---|
Kg/t | 2.7 | 0.5 | 3.6 | 2 | 0.9 | 0.9 |
B | Cu | Fe | Mn | Mo | Zn | |
---|---|---|---|---|---|---|
Mg/Kg | 10-50 | 1-10 | 30-100 | 10-50 | 0.1-1 | 10-50 |
Ref: Christou et al. 1999
Dynamic of nutrient uptake over a crop season in tomato
The highest nutrient absorption occurs within the first 6 to 16 weeks of growth, with another peak following the initial fruit removal. Hence, the plant needs a substantial nitrogen application early in the growing season, followed by additional applications after the fruit initiation stage
Role of nutrients
Key parameter | N | P2O5 | K2O | MgO | SO3 | CaO |
---|---|---|---|---|---|---|
Yield | + | + | + | + | + | |
Vegetative growth | ++ | + | + | + | + | |
Fruit setting | - (*) | |||||
Fruit number | + | |||||
Fruit firmness | + | |||||
Fruit color | + | ++ | ||||
TSS | + |
(*) Excess of N fertilization can delay the reproductive stage
Nutrient deficiencies
Nitrogen
General chlorosis of the older leaves on a plant. Slower growth and smaller plants; Less flowers and reduced yield.
Phosphorous
Plants develop very slowly, are stunted even at maturity; Brighter color than normal, lower leaf surface is grey-green. Leaflets roll upwards under severe deficiency; It occurs on calcareous and heavy soils, where P can be fixed.
Potassium
Potassium is the nutrient most extensively extracted by tomato plants. A 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
Calcium
Blossom-end rot (collapsing of the distal part of the fruit). Deficiencies are severe in soils with pH below 5, salinity, heat and cold weather.
Magnesium
Symptoms appear first on older leaves, general chlorosis while veins remain green. In severe cases, scorched appearance due to interveinal necrosis. It may occur on sandy soils, and when too high K or Ca rates are applied.
Sulfur
Symptoms are similar to N deficiency, but the chlorosis is uniform and general throughout the entire plant, including younger leaves. Typical reddish color develops on leaves’ petioles and veins.
Boron
Symptoms generally start on young leaves, as lighter color, severe deficiency shows on older leaves as interveinal chlorosis, which develops to deep yellow-orange hue. Brittle leaves that may show rolled-up edges, corky stem-end of the fruit in tomatoes.
Chlorine
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 there appears a characteristic bronzing on the upper side of mature leaves. It can be found in highly leached inland areas.
Copper
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.
Manganese
At the earlier stages, light chlorosis appears on the young leaves, at more severe cases, mature leaves show netted veins. Then leaves develop brown-grey necrosis along the veins. It occurs on high-pH-, and calcareous soils, or excessively limed soils.
Molybdenum
An early symptom for molybdenum deficiency is overall chlorosis, very similar to nitrogen deficiency, but without the reddish coloration on the undersides of the leaves. An upward cupping of the leaves and mottled spots, developing into large interveinal chlorotic areas under severe deficiency.
Zinc
It causes stunting of plants and upwards 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.
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