Detailed instructions for nutrient solutions when using this common commercial system is provided by the University of Florida's George Hochmuth in an excellent extension bulletin:
edis.ifas.ufl.edu/cv216
I have attached a copy.
Hi Christos, in my opinion all nutrient solution is good for growing tomatoes (Steiner, Hoagland, etc.). For me, is most important the management of EC and pH during the day (high EC in the morning and low EC during the noon) and during the season (winter, spring or summer). Too, you can modify the solutión with N:K ratios, but is not commun and less practical in commercial productions, however can possibly work in little experiments. Please take in consideratión too, the water requieriments of plant during the day. The plant need most water at noon that minerals (low EC; 1.5, 1.8), but during the morning you can obligate at the plant to send energy at the root system for catch water and in consecuency the root system will grow (high EC 2.5- 3.0). Salutations.
The concentration of essential nutrients to the tomato crop, cultivated in rockwool slabs, in parts per million (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, Mo), according to Papadopoulos (1991), vary depending the stage of plant growth: 201, 62, 253, 247, 36, 0.8, 0.57, 0.32, 0.22, 0.1, 0.005, for saturation of slabs; 238, 62, 370, 190, 36, 0.8, 0.5, 0.32, 0.22, 0.1, 0.005, for 4-6 weeks after planting; 200, 62, 370, 190, 36, 0.8, 0.57, 0.32, 0.22, 0.1, 0.005, for normal feed; 203, 62, 390, 190, 36, 0.8, 0.57, 0.32, 0.22, 0.1, 0.005, for heavy fruit load.
In soilless culture, tomato can tolerate total salt concentrations of up to 3.0 dS/m in the root zone without yield losses. The exact level may vary depending on other circumstances such as e.g. the cultivar sensitivity and the environmental conditions.
Proper management of the salt concentration of the nutrient solution can provide an effective tool to improve the product quality.
To talk about adequate nutrient solution, you must understand two concepts:
On the one hand, the composition of the solution (which is depending on the needs of elements in each phenological stage and may vary according to the needs of each cultivar), so the information provided by Thomas Björkman is very interesting
On the other hand, you should also consider the concentration of application (which is direct function of the water demand and the climatic conditions). To control this factor, you must obtain information about the vapor pressure deficit (VPD) of the environment in which you do the crop.
I am grateful for your answer and I would like to thank for this special dedication.
I've started an experiment and I want to try an alternative fertilization in order to reduce the risk of blossom-end red.
The current concetration of essential nutrients is for 5 stage of tomato growth as follows (s. attachment).
In which stage of growth the concentration of the above, in your opinion shall be changed;
PS. Mr. Santamaria why did not use Papadopoulos (1991) sulphur in the nutrient soultion?
Sure! Usually the sulfur reaches sufficient concentrations due to the addition of K2SO4 and MgSO4.
In my last experiment on tomato grown in pots with perlite, I used 0.670 g / L of Ca (NO3) 2 +4 H 2 O, 0.02 g / L of NH4NO3, 0.255 g / L of KNO3, 0.19 g / L of K2SO4, 0.470 g / L of MgSO4 +7 H2O, and 0.22 g / L of KH2PO4, dissolved in 1,000 liter of water, plus micronutrients.
To have 140, 10, 240, 50, 45, 124, and 94 ppm, respectively, of N-NO3, N-NH4, K, P, Mg, Ca, and S.
I recommend Soilless Culture: Theory and Practice by Lieth and Raviv...
I recommend read and use the Nutrient Solution (NS) calculator is an EXCEL™ spreadsheet developed by Dr. Luca Incrocci (Dipartimento di Biologia delle Piante Agrarie, University of Pisa) to assist growers and consultants in the calculation of salts concentrations of nutrient stock solutions.
http://www.wageningenur.nl/en/Research-Results/Projects-and-programmes/Euphoros-1/Calculation-tools/Nutrient-Solution-Calculator.htm
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