Ammonium Sulfate Fertilizer
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Ammonium Sulfate Fertilizer


Use our Ammonium Sulfate fertilizer on your onions, garlic, elephant garlic, shallots and leeks to increase bulb size, flavor and maximize harvests. This special blend provides essential nitrogen and sulfur to improve foliage production, which will subsequently result in larger bulbs. Use as a side-dress.


Our Ammonium Sulfate fertilizer is the perfect blend for growing onions, garlic, elephant garlic, shallot and leeks. These crops are heavy-feeders, meaning they require significant amounts of nutrients (nitrogen and sulfur) and water throughout their initial growth phase.

Allium species (onions, garlic, elephant garlic, shallots and leeks) generally have two growing phases throughout the life of the plant. The first phase is called the "vegetative phase." During the vegetative phase, plants are focused on maximizing foliage or green growth. This foliage will then be used to synthesize sugars and form the bulb that will be harvested in the second stage. As such, the second stage is appropriately named the "bulbing phase."

The more foliage that is generated during the vegetative stage, the larger the bulb that will be produced during the bulbing stage. In onions and shallots, each leaf represents a ring on the eventual bulb. Therefore it is important to provide the nitrogen and sulfur needed to get as much leaf growth as possible during the vegetative stage. This will result in large bulbs and bountiful harvests.

Ammonium Sulfate provides a fast-acting source of nitrogen and sulfur. Used as a side-dress, sprinkle the fertilizer to the side of the plants without getting it on the plant leaves. 

Ammonium Sulfate Use Recommendations

Begin applications three weeks after transplanting. Repeat every 3-4 weeks. Side-dress 1 cup per 20 linear feet of row. When side-dressing, always water immediately after feeding.

If injecting through a drip irrigation system, half the rate and dissolve 1 cup per 40 linear feet of row.

Guaranteed Analysis

  • Total Nitrogen (N) - 21.0%
    • Ammoniacal Nitrogen - 21.0%
  • Sulfur (S) - 24.0%

Customer Reviews

Based on 1 review
HM Ballard
5 out of 5

Rapidly dissolves in water and feed through a siphon nozzle. Makes fertilizing easy.