July 1, 2024

VIDEO: NPK for growing Hydroponic Tomatoes: What is 4-18-38 and how to mix One Gallon recipe of Masterblend


In this video I explain what the Masterblend formula is and how I mix it up for a one gallon recipe. I also cover the basics of NPK and what the numbers 4-18-38 stand for. I find this hydroponic nutrient solution works very well for my fruiting plants such as tomatoes, cucumbers and peppers. It is also very economical since you use so little at a time.
Amazon links to items mentioned in this video:
Masterblend 2.5 pound combo kit: https://amzn.to/2PfKpji
Grow Big hydroponic fertilizer: https://amzn.to/3r7JAX4
Scale with decimals for grams: https://amzn.to/3f92F8C

30 thoughts on “VIDEO: NPK for growing Hydroponic Tomatoes: What is 4-18-38 and how to mix One Gallon recipe of Masterblend

  1. I enjoy your videos. Last year I finally gave up on trying to grow in the soil in Florida after three years of trying so I may setup a small greenhouse with hydroponics so I can grow my own vegetables. The molds, gigantic grasshoppers, inch worms and countless other things including poor soil and nearby massive oak trees sucking up all the nutrients I put in the ground defeated my garden attempts lol.

  2. thank you for sharing your hydroponic knowledge and science base experiments. I have had following your channel and almost watched all of your videos. Because I am living in a rural area and in my country hydroponic solution is not available, I had to commute to the nearest city, buy hydroponic elements from chemical stores, and mix them. with this background, all of my hydroponic knowledge is YouTube and the internet base. Hopefully, at this time which this comment is written tomato, cucumber, onion, potato, chili pepper, and garlic planted and harvested on an experimental scale. I would like to share my experience with you. about mixing nutrient elements, in my view,  two measurement tools are important which are PH and TDS meter. PH meter is important because roots can absorb dissolved nutrients best in a PH between 6.0 to 6.5. About cheap pen PH meter, it is very important that the tool has a calibrate function because these PH meters measure PH by using a tiny ultraviolet lamp which its ultraviolet radiant strength changes over time and result in the wrong measurement. This issue is very important because PH numbers calculate in a logarithmic system which means +/-1 unit mistake in measurement causes +/-10 units mistake in reality or +/-10 times acidic solution which may cause roots to burn or roots nutrient absorption failure. So, it is necessary to check and calibrate the PH meter at least every weak.

    TDS measurement tools are necessary because it shows the amount of nutrients dissolved in hydroponic solution. Monitoring the TDS of a hydroponic solution is important because total dissolved salts less than 700 ppm cause slow or stop growing in plants and more than 1500ppm causes roots nutrient absorption disability. According to my experience, for a leafy and growing stage of plants TDS around 700 ppm, for flowering stage 1200ppm and fruity stage 1500ppm is ideal. By using these tools, growing plants such as cucumber in a small pot are possible. By checking the PH and TDS of a solution every 7 to 10 days gardeners can judges about nutrients available in the solution and the plant's health.

    For making nutrient solution I used this method.

    First, the TDS of water is measured. If the measurement number is above 250ppm the water will be soldered. For example, 200ppm water is not bad and 100ppm to 130pmm is ideal because more nutrients can be added to the water.

    Second, PH is measured and regulated around 6.2 or 6.3. I use phosphoric acid as a PH down solution.

    Third, the TDS of the solution measured again because PH regulation increases the TDS number, therefore for the calculation of the next step, it should be measured again. For example TDS of the water after PH regulation changes to 250ppm.

    Fourth, the difference between TDS of regulated water and ideal TDS divided by 5 because elements ratio, in general, is 2 unit N.P.K, 2 unit Calcium Nitrate, and 1 unit magnesium sulfate. For example TDS of regulated water is 250ppm and the ideal ppm is 700 therefore 700-250= 450ppm.

    (450ppm/5) = 90 ppm

    And N.P.K, MgSO4, Ca(NO3)2 ratio is 2,1,2.

    N.P.K = (90*2) =180ppm

    MgSo4 = (90*1) = 90ppm

    Ca(NO3)2 = (90*2) = 180ppm

    For mixing nutrients it is better to dissolve each element in a separate and small bottle (250cc) until making each solution saturated.

    Then, 180ppm N.P.K added to the water

    Solution = 250ppm(water)+ 180ppm(N.P.K) = 430ppm

    After that, as you mentioned, because Ca and Mg in a concentrated container make sediment it is better to add Epson salt before Ca to the solution.

    Solution = 430ppm(solution) + 90ppm(Epson salt) = 520ppm

    Finally, dissolved Ca added until TDS meter shows 700ppm

    Solution = 520ppm(solution) + 180ppm(Ca(NO3)2) = 700ppm
    Checking solution every 5-10 day is recommended. If solution level decreased and TDS increased, add regulated water. After adding water if TDS decreased lower than 700ppm, add dissolved nutrients with 2,1,2 ratio.
    Good luck

  3. I've started to mix a 4X strength in a single milk jug. It seems to be stable still at that concentration. Diluting for use is still relatively simple and cuts down on the jugs used.

  4. I for one will be trying the master blend for the first time this year and I have read that not mixing in the correct order could be problematic , thanks for the one gal mixing. I have a digital scale that reads in lbs and grams and has 3 decimal places so I should be ok for mixing.. Im still waiting on the calcium nitrate which I should receive any day now looking forward to trying a first 1 gal. test mix.

  5. actually those are not undissolved calcium nitrate, calcium can react with "sulfate" and "phosphate" in your solution. And that formed calcium sulfate and calcium phosphate which is insoluble in water.

  6. i know its plants so daily updates are not very entertaining but… any updates 🙂 i like watching your content cause of the way you explain things

  7. Thanks for another excellent tutorial, Tikki! I've been looking for a more economical solution for nutrient solutions and I really appreciate what you've shared here!

  8. I mean curious whether these masterblend are organic nutrients or synthetic?? Does these work in soil . Also can these tomato masterblend will work for radish and other fruits plants ??

  9. I don't have a decimal scale, so may I take 3 jars ( masterblend, epson salt and calcium) and add 5 oz of water in each and add 12g ,6g 12g of nutrients in each?

    So when I need just 1 gallon of nutrient I would add 1 oz of each jar?

    Will this concentration be good for 2 months?

  10. on the masterblend instructions at 5:24 it has by volume of approx 2 tsp of all 3. Is the Epsom Salt lighter crystals or was that a typo on their packaging?

  11. I'm curious why you prefer Grow Big for greens. Have you simply seen better results? I'll be growing some microgreens and lettuce and am looking for the correct fertilizer to use.

  12. Hey Tikki – love your videos. Can you explain to me why you mixed 5 separate gallons? Is it because you won't use them all and store them? When I am mixing for 15 gallons, I just put 15 gallons worth of product into a one gallon container and mix it in there then pour it into the 15 gallons. Do you not recommend that?

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