ONION GUIDE OF FERTILIZATION
Jun 06, 2017

Growing onion and getting high yield is a task that requires profound knowledge and expertise. Best fertilization regime should be based on leaf or soil analysis. Here are just some of the information for reference:

ONION

The onion (Allium cepa L., from Latin cepa "onion"), also known as the bulb onion or common onion, is a vegetable and is the most widely cultivated species of the genus Allium. Its close relatives include the garlic, shallot, leek, chive,and Chinese onion.

Red, yellow and white are the three groups of onions widely cultivated in the world.

The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season.

Onions are cultivated and used around the world. As a food item, they are usually served cooked, as a vegetable or part of a prepared savoury dish, but can also be eaten raw or used to make pickles or chutneys. They are pungent when chopped and contain certain chemical substances which irritate the eyes.1204203205-0.jpg
















Crop Guide

Onions are best cultivated in fertile soils that are well-drained, high in organic matter, neutral pH. Optimum pH is 6.2 to 6.8. Requires plentiful, even moisture for good yields. Sandy loams are good as they are low in sulphur, while clayey soils usually have a high sulphur content and produce pungent bulbs. Onions require a high level of nutrients in the soil. 

Bulbing onions are day-length sensitive; their bulbs begin growing only after the number of daylight hours has surpassed some minimal quantity. Most traditional European onions are referred to as "long-day" onions, producing bulbs only after 14 hours or more of daylight occurs. Southern European and North African varieties are often known as "intermediate-day" types, requiring only 12 to 13 hours of daylight to stimulate bulb formation. Finally, "short-day" onions, which have been developed in more recent times, are planted in mild-winter areas in the fall and form bulbs in the early spring, and require only 11 to 12 hours of daylight to stimulate bulb formation. Onions are a cool-weather crop and can be grown in USDA zones 3 to 9. Hot temperatures or other stressful conditions cause them to "bolt", meaning that a flower stem begins to grow.

Onions have shallow root systems and need consistent moisture and good weed control. Water weekly if weather is dry, and mulch to retain moisture and suppress weeds. Due to shallow root system the fertilizers should be banded 8-10 cm below the seed row.

Recommended average rates of nutrients for onions:

170-400 Kg N/hectare

75-150 kg P2O5/hectare

200-300 kg K2O/hectare

20-40 kg MgO/hectare

Fertilizers management: 

Phosphorus is often present in sufficient quantities, but may be applied before planting because of its low level of availability in cold soils. 

Nitrogen and potash can be applied at regular intervals during the growing season, the last application of nitrogen being at least four weeks before harvesting.

Doses of fertilizers, type of fertilizers and irrigation affects the storing capacity of onion / shelf life of onion. Organic matter increases the storing capacity of onion.