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Apples to Apples Hydroponics - Nutrients

NPK, TDS, and pH readings were done on Jan 5, 2001. Where the Micro solution is above what is recommended (1250-1300) due to the addition of nutrient solution in December without water changeover to discard previously added solution, the NPK for this solution did not register the highest - worm bed drainage solution did! The numeric measurements mean:

0 = Depleated
1 = Deficient
2 = Adequate
3 = Sufficient
4 = Surplus


Growth in the worm bed drainage solution is keeping pace with the Micro plants, even through they are further away from the 1,000 Watt Halide light (the Micro being directly under this light). The plants appear, in some leaves, to have a slightly yellowish tinge, where almost all leaves in the Micro solution are simply green. Another difference noted was that algae is growing in the Micro solution where the solution has splashed around empty pot holes. This has not occured in the worm solution, although there are empty pot holes and splashing there too. Since the pH seems to be similar, if not the same, in both solutions, there is no explanation for this difference. Correspondence with a Hydroponics association by Gabe on our success with worm bed drainage solution resulted in an e-mail confirming that hydroponics can be grown in this solution, with lettuce being mentioned as a success.

  1. Fish water nutrients are measureable, and the plants struggle on. The Navy Beans and Peas are doing the best, continuing to grow, but the French Beans have given up and died, never really putting out leaves beyond the seed leaves. The Spinach sproutling still has only the seed leaves, and the Pepper has sprouted. The Basil, being the first to sprout in the fast racing fish water, died soon after sprouting. The Rocket and Chinese Cabbage are at long last putting out secondary leaves. The Watercress continues strong, with new growth, in the floating mass in one of the tanks. TDS in the fish tanks, where nutrients are collected by the plants as soon as they become available, struggles along at 249.
  2. Worm water continued to increase in TDS from a reading of 1118 on Dec 5th to 1193 on Jan 5th. This in spite of plant growth keeping pace with the Micro plants and no additional nutrient added. An explanation for this timed release phenomena was given by a Yale bio-scientist, who speculated bacterial action on suspended particles, and confirmed by Darryl Jones of the Vital Earth company in Perth, AU. Darryl stated that if the solution is kept in the dark, it will increase over time in the months after being gathered due to bacteria action. The strength of this increase was observed in 2 gallons of reserve solution set aside in a covered plastic container, which almost doubled in value to a TDS of 1523 in the three months following collection. These last two gallons were added to the 23 gallon reservoir on Jan 5th, as it had dropped due to evaporation. The mix then measured a TDS of 1240. This grew to a TDS of 1346 by January 24th.
  3. The Micro solution, which had been replenished on December 5th with an additional 1/3 total nutrient solution, rose not only to over 1300 but to over 1400, as measured on Jan 5th. The Navy beans showed some nutrient burn from this, with a slight curl on some leaves, but otherwise the plants seemed unaffected. (Nutrient solution with a TDS above 1300 can creat a nutrient burn problem in hydroponically maintained plants.) This had dropped to a TDS of 1364 by January 24th.