Growing Onions: A Guide to Planting and Production

Introduction to Onion Cultivation and Production:

Onions are one of the most widely consumed vegetables in the world, especially with the ease of cultivation and care, and there are multiple dates for planting onions in Egypt and around the world, each according to the appropriate weather conditions and planting dates also differ according to the purpose of cultivation. Onions are an essential ingredient in many dishes because of their many health benefits, which can be summarized as follows:

Health benefits resulting from eating onions:

* Strengthening the immune system:

Given that onions contain many essential and beneficial nutrients for the body, eating them strengthens the immune system and reduces the incidence of infectious diseases.

* Maintaining heart health:

Onions contain nutrients that reduce the formation of triglycerides and lower cholesterol in the body, contributing to maintaining heart health.

* Protects you from cancer:

Onions contain a high percentage of antioxidants, so eating onions daily reduces the incidence of cancer of all types, especially colon cancer.

* Maintaining blood sugar levels:

One of the most prominent benefits of eating onions is regulating blood sugar levels, so it is recommended to eat them at breakfast to control and reduce exposure to high blood sugar levels.

* Strengthening bones:

It strengthens bones, maintains their health, and reduces their exposure to fractures, so it is recommended that you eat them daily.

Types of soil for planting onions:

Before planting onions, it is necessary to understand the different types of soil and their properties. The three main types of soil are sandy, clayey, and loamy. Sandy soil consists of larger particles and has a sandy texture. It drains quickly and does not retain moisture well. Clay soil is a mixture of sand, silt, and clay and is ideal for planting onions. It retains moisture well and provides good drainage. Clay soil consists of small particles and has a dense texture. It retains moisture but drains poorly.

* The soil's pH level also plays a crucial role in onion production. Onions prefer slightly acidic soil with a pH range of 6.0 to 6.8. Alkaline or very acidic soil can affect onion growth and yield. 

Suitable weather conditions for growing onions:

Onions are cold-weather vegetables that can withstand light frosts. The ideal temperature for seed germination is around 18°C, but onions can germinate in a wide range of temperatures, from 0 to 35°C, with the best results seen between 8-28°C.

Seed germination takes approximately four and a half months at 0°C, and the plant thrives at a temperature of 12-24°C. Optimal growth and bulb quality are achieved when the temperature is relatively low during the early stages of plant growth and relatively high near bulb maturity. 

However, regardless of the growth stage, dry weather at harvest is crucial for successful drying. Onions are considered long-day plants for bulb formation, as bulbs do not form if the length of the night exceeds a specific limit. Although the varieties vary significantly in the light period necessary for bulb formation from 12 hours or less to 16 hours or more, onions of all varieties are considered long-day plants. 

This... and varieties that require long days cannot be produced in areas where the day is shorter than the requirements of these varieties because they do not form bulbs there. Likewise, an economic crop cannot be produced from varieties that are sufficient for a relatively short day in areas where the day is longer than the requirements of these varieties because they tend to form bulbs quickly before they have an excellent vegetative mass; thus, the crop is reduced, and the bulbs are small in size.

Onion cultivation:

There are many types of agriculture worldwide, and each region has a reputation for its kind of agriculture. Some countries specialize in onion cultivation, while others are famous for growing apples and other crops. Onion cultivation, based on any soil type, is considered one of the easiest crops to grow.

Preparing the soil for onion cultivation is done in several stages:

1. Organic fertilizers can be added by spreading them entirely on the soil's surface and plowing the land well. Fertilizers can also be added by making small holes at the edges of the seedlings.

2. Dividing the agricultural land into longitudinal or transverse rows so the farm work is organized without problems occurring during growth between the agricultural seedlings.

3. Separating the agricultural seedlings at specific and regular distances, as the distance should be between thirty centimeters and forty centimeters.

4. Isolation periods should be organized equally, and no diseases that appear if they exist, such as downy white and powdery mildew, should be neglected.

5. The method of planting onions on agricultural land must be identified and is done in a number of the following stages:

*. Bring several onion seedlings from any source, and this number is calculated according to the area of the land. Cut the upper green parts to stimulate them to produce roots.

As mentioned previously, turn and prepare the soil for the pores to be light.

* Make small holes with any sharp tool, then place one onion seedling in each hole.

* Water all seedlings regularly. Onion cultivation requires large amounts of water, especially in the first days. If the soil is sandy, it must be watered once every two or three days.

* Fertilization is done about a month after planting with liquid organic fertilizer or manufactured fertilizer.

Harvesting and Storing Onions:

It usually takes 80–100 days after sowing for onions to be ready for harvest. Spring-planted onions can be harvested in mid-summer. The onion crop is ripe when the tops fall off on their own.

When onions are ripe, their tops turn yellow and begin to wilt. To speed up the ripening process, the tops can be folded over.

Loosening the soil allows the onions to dry faster. Once they are dry, they can be harvested in late summer. Note that if there are wet onions, it is best not to store them as they can quickly rot.

When harvesting your onions, pull them out of the ground and let them dry for two weeks. Watering lightly just before harvest can make the process easier. Once all this is done, store them in a cool, dry place like a basement. Never put your onions in a plastic bag.

Some diseases and insects that affect onions

1- Sclerotium Cepinorume

It is a dangerous and rapidly spreading disease, which appears as white fluff covering the onion tissues as they rot and dry out. The infected leaves twist at the base, shrink, turn yellow, wither, and dry out, and the roots are affected by the infection, making it easy to uproot the plant. There is no cure for this disease, but the following measures prevent it:

Do not use seedlings from infected spots or throw infected plants or their remains in the garbage. Instead, burn them and not plant onions in previously infected land.

2- Pronospora Schleideui or Mildiou

It appears as purple fluff on the outer surface of the leaves. Within a day or two, the infected leaves change to blue, then dry up and fall off.

If the plants are infected when they are young, their leaves dry up and die. If they are large, the leaves may die, and the onion may remain, but it remains small or is delayed in maturing.

Resistance: Take the measures mentioned for the previous disease. Spray the infected plants outside with a Bordeaux solution consisting of 1 kg copper sulfate, 1 kg quicklime, 75.0 kg soft soap, and 5.12 gallons of water.

Among the insects, it is worth mentioning:

1- Onion fly Amthomya ceparum

It is a small black fly, a deadly insect to onions, but its larvae are small white. It penetrates the onions and spoils them. It occurs most often in wetlands and years. It is resisted by conducting a general campaign for all worms and destroying them.

2- Onion thrips tapas

A small yellow or dark black insect pierces the leaves with its mouth and sucks the juice from them; its effect appears on the leaves in the form of silvery white spots next to its brown, collected feces; it leads to twisting and drying of the leaves, it is treated by spraying a solution of nicotine sulfate and strengthening the plants with agricultural methods so that they resist the insect as much as possible.