Nitrogen

Nitrogen (N) is needed for the synthesis of amino acids, proteins, chlorophyll, nucleic acids and coenzymes.

Tomato plants cannot make their own nitrogen so there must be some present in the growing media for them to thrive. When fertilizing tomatoes this nutrient is usually the most needed.

Plants asborb nitrogen mostly as inorganic forms such as nitrate (NO3-) and also as ammonium (NH4+) or amino (NH2+) ions. Since most soil nitrogen is in the organic form, it must be oxidized first by soil organisms into the inorganic forms in order for the plant to use it.

Nitrogen fertilizers can also effect pH of the soil.

Various sources of nitrogen can be used when fertilizing tomatoes.


Various Nitrogen Sources

    Inorganics

    • ammonium nitrate
    • ammonium sulfate
    • anhydrous ammonia
    • calcium nitrate
    • potassium nitrate
    • sodium nitrate
    • urea

    Organics

    • alfalfa meal
    • blood meal
    • compost
    • feather meal
    • fish meal
    • legumes (tilled in)
    • manures



Inorganics

    Benefits

    • quick release to the plant
    • lower volumes required
    • able to fertigate

    Drawbacks

    • can lead to salt build ups
    • easier to "over-fertilize"
    • can "burn" roots or foliage

Organics

    Benefits

    • slow release to the plant
    • often adds organic matter
    • most do not "burn" roots or foliage
    • some can be used to temporarily repel animals (bloodmeal, hair)

    Drawbacks

    • over use of manures can lead to excessive salt build ups
    • often larger volumes to apply
    • some are "smelly"
    • potential source for human pathogens (manures, blood meal, bone meal)


Signs of Nitrogen deficiencies


Conditions which favor deficiencies



Nitrogen excess



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