Propagation Structures in Horticulture

In horticultural practices, various structures are used to provide optimal conditions for plant propagation. These structures protect plants from external environmental factors, enhance growth, and ensure healthy development. Below are the different types of propagation structures:

1. Polyhouse

• Definition: A polyhouse is a type of greenhouse covered with plastic material, typically made of polyethylene, to create a controlled environment for plant growth.
• Purpose: Polyhouses are used to grow plants in a protected, controlled environment. The plastic cover allows light to enter while maintaining a consistent temperature and humidity inside, regardless of external conditions.
• Applications: Ideal for growing high-value crops such as vegetables, flowers, and fruits. It helps in extending the growing season and preventing crop damage due to weather conditions.

2. Net House

• Definition: A net house is a greenhouse that uses netting material as the covering, instead of plastic or glass. This allows for partial shading and protects plants from direct sunlight and pests.
• Types:
  • Half Shade Net House: Provides moderate shading and is suitable for plants that require partial sunlight.
  • Complete Net House: Offers more comprehensive shading, ideal for plants that are sensitive to excessive sunlight.
• Applications: Used for growing crops that need protection from direct sunlight, such as vegetables and ornamental plants. They are also effective for controlling insect infestations.

3. Plastic Tunnel

• Definition: A plastic tunnel is a smaller version of a polyhouse, typically constructed on an arch-shaped steel frame and covered with plastic. It is simpler and less expensive to build compared to a full polyhouse.
• Purpose: Plastic tunnels are used to create a protected growing environment for crops. They provide shelter from extreme weather conditions like wind, rain, or frost.
• Applications: Suitable for growing small plants such as vegetables, flowers, and other low-growing crops. Some plastic tunnels are portable and can be moved to different locations when not in use.

4. Mist Chamber

• Definition: A mist chamber is a specialized structure used in plant propagation where water is sprayed in the form of a mist to maintain high humidity and provide optimal conditions for root development.
• Purpose: The mist helps retain a continuous film of water on the leaves, reducing transpirational loss and maintaining turgidity. It also prevents disease infections by washing away fungus spores before they can attack the plant tissue.
• Water Requirements: Water used in mist chambers should have good pressure, be free from salts, and have a pH level between 5.5 and 6.5.
• Applications: Often used in the propagation of cuttings, where high humidity is essential for root formation and overall plant health.

Plant Growing Structures / Containers

In nurseries and greenhouses, plant seedlings, saplings, and rootstocks are grown in containers. The containers used for propagation serve multiple purposes, such as ensuring uniform growth, improving quality, and providing ease of maintenance.

Advantages of Containers in Greenhouse Production:

1. Uniform Production: Ensures uniformity in plant growth and development.
2. Quality Production: Helps in producing high-quality planting material.
3. Easy Maintenance: Simplifies care and management of plants, as containers can be moved easily.
4. Reduced Production Time: Containers speed up the production process by providing ideal growing conditions.

Types of Containers:

• Plastic Pots: Commonly used for seedlings, saplings, and potted plants.
• Trays: Used for seedling propagation and are often used in conjunction with mist chambers.
• Cell Packs: Small individual cells that are ideal for growing plants in controlled conditions.

Storehouse

A storehouse is an essential structure in horticulture for storing various materials such as fertilizers, tools, and planting materials like seeds, bulbs, corms, and tubers.

Features of a Storehouse:

1. Two Compartments:
   • One for storing fertilizers, implements, and tools.
   • One for storing planting materials such as seeds, bulbs, corms, and tubers.
2. Ventilation: A well-ventilated environment is crucial to prevent the growth of mold and to keep planting materials in good condition.
3. Material: Storehouses are generally made from brick and mortar, and the seed storage compartment often contains wooden or bamboo shelves to keep planting materials organized.