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pH and Nutrition (Part 3)

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pH and Hydroponics

Most plants generally prefer a slight to mildly acidic nutrient solution with a pH between 6.5 and 5.5. In part this is because at in alkaline conditions, certain nutrients become less available to the plant. At a pH of 7.5 or higher, iron availability decreases, and Potassium (K) also becomes more stable and less available in alkaline environments. Nitrogen (N) has the best uptake around neutral (7), but the micronutrients manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), and boron (B) are more available under slightly acidic conditions. Conditions with a pH of less than 5.5 can hinder beneficial microbial growth. In very acidic conditions (4.0-5.0) the manganese (Mn) and iron (Fe) can become so available that they become toxic to the plant since with nutrients, more is not always better.

In hydroponics, the pH range of 6.5 to 5.5 is best for allowing for the plants to take up the full range of nutrients.

pH and Soil

Many fertilizers will tend to decrease pH, so lime is often added to soil to “sweeten” or raise pH. Sulfur can be added to lower the pH to “sour” it, but so do many nutrients and organic materials, so it is often not needed. In general the processes are slower and gentler in organic gardening, and to some extent are self correcting, so pH is not as critical of an issue unless it is well out of the normal range.

​ Aquaponics!

Aquaponics is like hydroponics’ cousin from out of town. You’ve probably heard of it before, but you may not have been properly introduced. These two growing philosophies have quite a bit in common. Both are soilless methods that rely on water chemistry for plant growth. Both are enclosed systems that require close attention to [...]

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pH and Nutrition (Part 2)

If you haven’t already, make sure to read Part 1Understanding pH ReadingsAcids have a low pH, and bases have a high pH, pure water sits in the middle at 7. The lowest number on the pH scale is 0, which is a very strong acid, and the highest is 14, which is a very strong [...]

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pH and Nutrition (Part 1)

pHWater also is known as H20 because it has two hydrogen atoms and one oxygen atom for each water molecule. From this base molecule, it can accept an additional hydrogen ion to become H3O, and become acidic. It can also lose a hydrogen ion to become HO, and become basic (alkaline). The pH scale is [...]

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