Fertilizer in Merom

  Fertilizer is one of the most important aspect of greenhouse operation.  Plants draw most of their necessary energy from the Sun in the form of photosynthesis, but they still need certain kinds of minerals to grow.  According to Carl, the recipe differs by location of the greenhouse because the climate and sunlight level are different.  And of course, the recipe differs completely among different variety of plants.  The list below shows the current recipe Carl uses for the bell peppers in Merom:

Tank A:

Ingredients	Amounts
Calcium Nitrate (liquid Ca)	2 container (1390kg * 2)
Potassium Nitrate (KNO3)	16 bags (25kg * 16)
Iron (liquid Fe)	4 buckets (= 64 bags 25kg solid Fe)

Tank B:

Ingredients	Amounts
Epsom Salt (MgSO4)*7H2O (Magnesium Sulfate, Heptahydrate)	21 bags (25kg * 21)
Potassium Nitrate (KNO3)	8 bags (25kg * 8)
Manganese	1500g
Zinc	3000g
Boron	4200g
Copper	600g
Potassium Chloride	2 bags (25kg * 2)

  There are 4 tanks of fertilizer mix, A1, A2, B1, and B2.  We refill and mix A1 and B1 while A2 and B2 are in use for irrigation.  When A2 and B2 run out, we refill and mix them while using A1 and B1 for irrigation.  We do this (1) to keep the fertilizer up and ready the whole time and (2) because fertilizers take a day of mingle to fully dissolve in the tank.  The four tanks can contain over 4000 liters, and the recipe above is calculated to, after dissolved in water, produce 4000 liter of mixture.

Tank A1 with Iron.

Tank B2 with Potash.

  The reason why we separate tank is that calcium and iron are better not mixed with Epsom salt in high concentration.  When they do, they form a solid precipitation that is hard to dissolve in water.  If the concentration is low, the precipitation does not occur; that's why we mix them together with water at the merge point.

  Note that no ingredient in the recipe above is 100% pure.  For instance, potassium nitrate we use is composed of, according to the minimum guaranteed analysis, 13.7% nitrate nitrogen (N-NO₃), 38.4% K, and 46.3% K₂O.  The detail of each ingredient will be added.

  Also, it is good to know that the cost of fertilizer is about $5,000 for single A and B tanks.  In summer, we mix the fertilizers about 4-5 times per week.  All other seasons we do it about twice a week.  So in summer, it costs about $25,000 a week just to prepare the food for the plants.  Wow, they better produce the darn crops!