Propagation Environments and Atmospheric Factors

Propagation Environments

• Nursery structures modify atmospheric conditions, such as temperature, light, and humidity, to optimize plant growth.
• Photosynthesis converts light energy into chemical energy in plants, using chlorophyll. Photosynthesis produces sugars from carbon dioxide and water, releasing oxygen as a byproduct.
• Transpiration is the loss of water vapor through stomata (pores on leaves) when carbon dioxide is taken in.
• Growers should manage atmospheric factors that limit photosynthesis, to maximize plant growth.
• Managing factors limiting plant growth is key to successful nursery management. The best possible environment should be designed.

Atmospheric Factors

• Limiting atmospheric factors include light, temperature, humidity, carbon dioxide, and organisms.
• Outdoors, the climate affects these factors.
• Propagation structures (greenhouses, for example) modify these environmental factors.
• Organisms, like insects, can be excluded from a nursery using proper design.
• Beneficial microbes can be encouraged.

Growing Medium

• Growing medium (substrate/potting soil) supports plant development.
• It should provide a suitable rooting environment, storage of air for the roots, water absorption and retention, and nutrients for plant roots.
• Various components, such as peat, coir pith, wood fibers, bark, and composted organic matter, are used to create growing media.
• The specific needs of different plant species dictate the best growing medium mix.
• Availability and sustainable development considerations affect the materials used in the horticulture industry.

Types of Propagation Environments

• Propagation environments are described as minimally controlled, semi-controlled, and fully controlled.
• Minimally controlled environments include open growing compounds with an irrigation system and a fence.
• Semi-controlled environments include various growing structures, ranging from cold frames to shade houses.
• Fully controlled environments, such as growth chambers and greenhouses, control most environmental variables, allowing year-round production.

Managing the Propagation Environment

• Horticultural techniques modify the propagation environment.
• Container type, volume, spacing, and other factors can alter plant size, quality, and type of crop.
• Good water supply and proper fertilizer use are essential for plant growth.
• Controlling light and temperature is important for plant growth, especially in greenhouses.

Growing Media

• Growing media, or substrates, are materials used for plant growth.
• They support proper plant development, providing essential elements.
• A suitable growing medium maintains physical stability, stores air, absorbs and retains water, and supplies nutrients.
• A wide range of media constituents are used, including peat, coir pith, wood fibers, and bark.
• Growing media are often formulated with additives like fertilizers, lime, and biological ones to optimize physical, chemical and biological properties for plant growth.
• Plant species have specific needs regarding water and nutrients, thus requiring various growing media mixes.

Creating a Homemade Growing Medium

• Composting is an excellent alternative to traditional growing mediums.
• Using native soils, or incorporating them into a growing medium, must be done carefully.
• Compost improves growing medium properties, including water retention, aeration, porosity, and fertility.
• Composting involves decomposing organic matter, modifying environmental conditions and managing variables like moisture, temperature, and carbon to nitrogen ratio (C:N).

Containers

• Container choice is crucial for nursery success.
• Factors like volume, height, diameter, shape, and material influence plant growth, cost, and operation in a nursery.
• Container sizes should be appropriate for the plant species, its volume, height and diameter.
• Container type, dimensions, filling, and harvesting methods affect operations in the nursery.
• Suitable container materials improve plant growth, minimize operational costs, and maintain quality.

Plant Density

• Spacing between plants influences light, water, nutrient availability, and plant growth.
• Spacing is specific to species, and plant type dictates spacing for optimum results in a nursery environment.
• Proper spacing is crucial for plant health and growth.
• Using the correct container type for plant species, is an important factor to ensure the best outcome.

Types of Containers

• Various container types are available, each with advantages and disadvantages (one-time-use, single, exchangeable cell, block, and others).
• Selecting the appropriate container type is essential for successful plant growth and nursery operations.

Cleaning Reusable Containers

• Cleaning reusable containers is essential for preventing the spread of disease and maintaining plant health.