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The Secret Of How To Grow Big Onions?

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Onions are the very first crops that are planted in the spring in the garden. Without these vegetables, no dish is unthinkable, and without them, it isn’t easy to achieve a refined and spicy taste.

Many gardeners grow onions, but there are many others, no less appetite and tasty in addition to this type. Onions are unpretentious, so they are grown everywhere, regardless of the region.

Many gardeners often wonder how to grow them to big onions. To do this, it is necessary to consider some of the plant’s features and provide the onion with all the conditions for the full development of the root crop.

The Secret Of How To Grow Big Onions
via Pixnio

How to Grow Big Onions

1. Consider the soil

Onions grow poorly on clay soil. This does not mean that there will be no crop on clay soil. It will simply be necessary to help the plants. It is essential to sprinkle fertilizer and sand on the bed and move it in clay soil.

Also, onions grow well in slightly alkaline soil. If your soil is acidic, add dolomite flour to deoxidize the earth. It is necessary to mulch the soil in advance. Hay and straw rot should be provided to create very favorable conditions for the growth of big onions.

2. Planting material

In addition to preparing the soil, you need to prepare the planting material itself. It is necessary to disinfect the seed bulbs. This is carried out either in hydrogen peroxide for 20 minutes or in a weak solution of potassium permanganate for 30 minutes.

During this time, all fungi and bacteria that are on the bulbs are quietly killed. It is best to trim the tops of the bulbs to stimulate the development and growth of feathers. Also, the tops of the feathers will turn out to be as even as possible.

3. Selecting and preparing a landing site

If this problem is solved correctly, you can get rid of some of the summer work. So, if the soil is thoroughly cleared of weeds, less weeding will be required.

When the onions are well fertilized, there will be no need for extra feeding. Also, there will be no need to puzzle over coping with the green bloom on the garden bed and the yellowing onion feather.

Do not forget about crop rotation. It is good to place these crops after tomatoes, potatoes, courgettes, and legumes. You need to make the bulbs healthy and not plant onions planted last year to grow big onions.

4. Planting period

Planting onions can be carried out in late autumn or early spring. In practice, spring planting of onions is preferable.

Climatic cataclysms of recent years can provoke early seedlings and their death during recurrent frosts, cause partial rotting of seedlings during the winter. The stress state of the plants will lead to the formation of small bulbs.

Depending on weather conditions and soil warming, onions are sown in warm regions in early April and early May. In the northern regions, after the frost passes, the soil warms about + 6 and + 10 °С.

Onion shoots will appear on the 5th-6th day. If you plant a seed in cold soil, it will begin to shoot. If you are late with planting, the onion will slow down its development once in dry and overheated soil and not form a big onion. So, to obtain a big onion, it is very important to withstand the planting time of the set.

Onion seedlings are patient to cold and easily tolerate short-term frosts down to -3 °С. But with the autumn planting and the onset of spring return frosts, the plants stop growing and developing when the temperature drops from -3 to -5 ° C, which subsequently affects the size of the bulb.

5. Onion care during the growing season

Keeping the soil moist, loose, and free of weeds during the growing season is very important. Weeds cover the bulbous zone and provoke fungal infection accumulation. Post-irrigation mulching of onions is mandatory.

The crust after irrigation becomes the reason for uneven moisture provision to an upper soil layer that reduces the possibility of forming a big onion. Loosening is only superficial, in wide aisles.

When loosening in a row, damage to superficially located roots negatively affects the growth of the bulb. Timely watering plays a significant role in the formation of a large onion.

The Secret Of How To Grow Big Onions 2 1

6. Watering and feeding onions

Watering and feeding onions in the first 2-3 months are essential. Interruption in the nutrient supply and irrigation regime violation results in small onion heads and loss of their taste.

Approximate frequency of watering:

  • The first month, watering is carried out once a week with the crushed mulch’s unintended subsequent loosening and mulching. Pests settle under considerable mulch, and fungal infection accumulates. Fine mulch protects the soil from drying out the top layer and quickly decomposes when exposed to moisture. During this period, when watering, the earth is soaked to a 10 cm layer.
  • In June, the watering period is reduced to a 10-day break by the bulb growth phase, but the soil is soaked to a 20-25 cm layer. To avoid stagnant water, watering is carried out with fine spraying.
  • In July, watering is carried out every 8-10 days as needed (preventing the soil from drying out in the root layer).
  • In the second half of July, the soil is only kept moist, switching to dry irrigation. The earth is loosened and mulched, and be sure to get rid of weeds.
  • 2-3 weeks before harvesting, watering is stopped and carefully “bare” the shoulders of the bulbs from the ground. The procedure promotes the maturation of the bulb, especially the stem at the base. Unripe stems in winter are affected by fungal and bacterial rot.

7. Fertilization

Onions use important nutrients from the soil, but they do not need to be fed. A consistent supply of nutrients and moisture during the growing season will contribute to the constant growth of the vegetative mass of the bulb.

From autumn, under the main digging of soil for onions, ripe crumbly humus is introduced no more than 1 / 3-1 / 2 buckets per square meter on depleted and dense soils.

Rye, mustard, oats, and rapeseed are well loosened. On dense loose soils, you can use mustard with vetch-oat, sweet clover, and legumes mixture. Mixed green manure crops will plow the ground and saturate it with existing nutrients.

Of the mineral fertilizers under the onions, only phosphorus-potassium fertilizers, 25-30 and 15-25 g/sq. m respectively are applied. In the spring, urea is added for sowing just 20-25 g/sq. m.

If the soils are depleted and higher fertilization rates are required, it is better to add 2/3 of the dose in the fall and apply the remainder in the spring before planting.

8. Lighting

Plant onions only in an open and sunny location or on the south side of buildings for big onions. Large onions cannot be obtained in partial shade or when the sun is not enough.

9. Protection of onions from diseases and pests

Plants are treated with bio fungicides (against diseases) and bioinsecticides (against pests) for preventive purposes to protect onions from diseases and pests. The most common bio fungicides are Gaupsin, Planriz, Alirin-B, Glyocladin, and Trichodermin.

For pest control, use Aversectin-S, Aktofit, Bitoxibacillin, Bicol, and Verticillium. It is better to prepare solutions for processing in tank mixes. The selection of biological products, their dosage, and mixing should always be performed according to the instructions.

Onions are processed at least 3-5 times during the growing season in the morning. Essentially, the last treatment can be carried out 2-3 days before harvest. Treatments are started at the first visible changes in feather color or plant condition.

10. Harvesting onions

The beginning of harvesting is determined by the state of the above-ground mass of the onion. Depending on the variety, the plant leaves turn yellow, lie down, lose turgor, and among others.

When harvesting, onions are pulled out of the soil and left for 1-2 weeks under a canopy for final drying. The dry onions are selected, and the dry root collar with the dense bulbs, covered with the dry upper-scale, is laid for winter storage.

Before placing in the storage container, cut the dried stems 3-5 cm on the braided or stump and hung them in a warm, dry place.

Growing big onions require careful agrotechnical techniques implementation. Typically, the primary technique includes selecting a zoned variety, seed quality, and timeliness of sowing.


To make onions grow big is not difficult at all. If you do not plan to set records but want to get a good harvest, choose varieties suitable for your conditions and follow the recommended agricultural techniques for them and you will undoubtedly succeed.

The compliance of the above includes timely watering and feeding, keeping the soil moist, weeding, and you will get big onions.