1. Preserving planted seeds, as most are expensive hybrid seeds, and any loss from planting directly with seeds leads to a massive loss for the farmer.

2. Possibility of performing the necessary service operations for the greenhouse during the seedling production period.

3. Ease of servicing nursery plants in a limited space inside the greenhouse.

4. Controlling disease resistance, whether in the nursery environment or on plants.

5. Seedlings should be produced with bulbs that contain a large portion of roots so that the plants are not exposed to seedling shock and continue to grow directly.

6. By controlling the appropriate temperature for growth inside the nursery, seedlings can be produced relatively quickly, mainly because they are grown in cold times.

The relationship between temperature and the amount of time needed for some seed germination 

From this, the most suitable temperature for producing seedlings is 25-30°C, provided in nursery land with limited space.

Certain vegetable crops require the planting of nurseries, which are easy to maintain and provide proper care for the plants.

As a result of the introduction of protected crops in Egypt, one purpose also became to produce seedlings under plastic tunnels or greenhouses to grow plants in open lands early or to grow them either in the tunnels themselves or in greenhouses as protected agriculture.

Among the crops whose seedlings can be produced under such conditions are tomatoes, peppers, eggplant, watermelon, cucumbers, and corn, which are grown under protected agriculture. Once the weather improves from the cold, the seedlings are transferred to open lands to benefit from the heating resulting from the use of protected agriculture in producing seedlings.

The success of producing good seedlings depends on the following:

1- Choosing good seeds for different crops.

2- Obtain seeds from a reliable source.

3- Treating seeds with chemical disinfectants.

4- Conducting some treatments to improve seed germination, such as soaking in warm water (25-30°C) for 24 hours or soaking in nutritional solutions such as copper or zinc sulfate or others at low concentrations for 24 hours.

5- Preparing the agricultural environment.

6- Preparing planting utensils.

7- Pay attention to the process of irrigation, fertilization, and resistance to various pests.

Containers used in seedling production

There are several containers used in the production of seedlings, and they must be characterized by the following:

1- It is possible to use it more than once.

2- It is possible to store it in a narrow compartment.

3- It must be light, non-rusting, pleasing in shape, and cheap.

4- It should not be significantly affected by external temperatures.

 

The most critical vessels used in seedling production are

1- Plastic pots.

2- Trays: Speeding Trays are made of plastic or Styrofoam and contain conical or round eyes. They contain several conical eyes ranging from 84 to 205 cone-shaped eyes that fill the eyes and plant seeds in them.

In addition, one-time containers may be used, including paper pots and paper trays

 3 - Jiffy cubes, the latter, are available in different diameters, are considered an environment for the nursery, and are planted with seedlings in permanent fields. Special machines may also make cubes from a soil mixture called soil. Blocks in which the seeds are planted and transported directly to the sustainable field and cubes of rock wool may be used.

Environments used in seedling production:

They are mixtures of types of peat moss with vermiculite, perlite, coarse sand, or sawdust mixed in specific proportions to give a suitable environment for seedling growth. The environment must be characterized by the following:

1. It acts as a storehouse of nutrients for the seedling.

2. It retains the necessary irrigation water for the seedlings while providing the appropriate amount of oxygen for aeration.

3. Provides the appropriate medium to stabilize roots and plants.

4. The environment must be wholly decomposed so that its size does not decrease significantly.

5. It should be of medium fertility and have an appropriate pH.

The nursery environment mixture must contain the following proportions of nutrients:

Nitrate nitrogen	100-250 ppm
phosphorus	125-450 ppm
potassium	75-150 ppm
Calcium	8-13 mEq/100g
Magnesium	1.2-5.3 mEq/100 g

 

Minor elements can be added at a concentration of 20 parts per million, provided that the pH is between 5.5 and 6.5.

Examples of some mixtures used in producing seedlings in pots:

 

Soil Blocks mixture

Components	Mixed 1	Mixed 2
Fine sawdust	60%	80 %
Sterilized loamy soil	25%	15 %
Sand	15%	5 %
Ammonium sulphate	3 kg / m3	3 kg / m3

 

Microelements in a solution are then added to the mixture and entered into machines to make cubes from them.

 

Sterilization of soil mixtures

The soil mixtures must be sterilized before planting the environment with any available disinfectant or benzamide at a rate of 200-250 g/m³ of the soil mixture and covered with plastic for 2-3 days. Then, the plastic is removed for ventilation, and the seeds are not planted before 10-15 days or at all. The toxic effect of the sterilization material will be eliminated to ensure that the environment is free of diseases and their causes, and it mustn't hurt the environment.

Seedling production steps:

Production of seedlings in containers:

Seeds are planted inside containers to produce seedlings by following the following steps:

1. Sterilize the trays or seedling pots before planting with any sterilizing materials such as formaldehyde or fungicides, then leave them for ventilation until the smell of the sterilizing solution disappears completely.

2. Fill trays or planting pots with the mixture prepared for planting seeds, then press them so that they are well compacted and do not have many air spaces, so they fall with the irrigation water after planting.

3. Holes are made in the soil, and each hole has a depth not exceeding 1 cm. Then, a camel seed is placed in each hole, covered with a thin layer of the mixture, and irrigated with water.

It is preferable to have a fungicide in an appropriate concentration so that fungi do not form on the soil's surface.

4. The trays are placed on wooden or iron stands so that a layer of air separates them from the soil medium, thus preventing the roots from penetrating the ground. They are wrapped around each other inside the cube until they are moved to a permanent place or placed on a plastic sheet if placed directly on the ground.

5. The seeds are watered continuously and kept at an appropriate temperature until they germinate and become viable

For transportation in a permanent location.

The soil should not be constantly wet throughout the seedling production process so that fungi do not grow on the surface. The nursery should also be watered in the morning, and irrigation should be avoided at noon because it increases the chance of sun blight.

Characteristics of a good seedling

The resulting seedlings must meet the following specifications:

1. The seedling should have solid vegetative growth and a dark green color. The stem should also be strong and free of symptoms of diseases and pests.

2. The root system should be robust and coiled inside the cube so the seedlings can be easily moved during transplanting.

The seedling growth period for protected crops ranges from 21-25 days for cucumbers and cantaloupes to 28 days for tomatoes and may reach 40-50 days for peppers.

The following specifications must be taken into account in seedlings when transporting them to the permanent field:

1. The seedling's growth must have reached 2-3 true leaves, other than cotyledon leaves.

2. The stem must be strong, woody, and free of diseases and pests.

3. The soil of the trays must be wet before transplanting to a permanent place so that the seedlings are transplanted ultimately without causing damage to the roots.

Planting seedlings in a sustainable place

* When the seedlings reach the appropriate size according to the previous specifications, they are moved to the greenhouse, and the following steps are followed when planting the seedlings.

1. The terraces are irrigated a day before planting until the soil becomes wet with water.

2. Dig holes deep into the soil cube or pot on one or both sides of the drip irrigation line, at a distance of 50 cm from each other between the plants in one row and 10-15 cm from the drip irrigation line on each side.

3. The seedlings are placed in the tray containing the soil, keeping the roots inside the dug holes and backfilling around them so as not to leave air gaps.

4. After planting them in a permanent place, the seedlings are watered for 2-3 days until the soil is wholly collected naturally around the plants. Then, they are prevented from watering for 2-4 days, depending on the soil type, to encourage the roots to grow in the soil, and then they are watered regularly.

5. The grafting process is carried out for unsuccessful seedlings after a week of transplanting and after ensuring that...

The success of the seedlings remaining in the greenhouse.

* Always consider the availability of 5-10% of the seedlings as a reserve after the first transplanting process so that the grafting process can be carried out.