Ornamental plants production is a critical area within horticulture that supports Kenya’s growing floriculture market and urban beautification initiatives. Preparing suitable planting materials is foundational to establishing healthy, vibrant ornamental plants that meet market demands and environmental conditions. This chapter focuses on the initial and essential step of nursery site selection, which directly influences the success of ornamental plant propagation and growth. Understanding the factors involved in choosing the right nursery site ensures optimal conditions for plant development and economic viability.

1.1 Nursery Site Selection

Selecting an appropriate nursery site is a strategic decision that affects the quality and quantity of ornamental planting materials produced. For horticulturists in Kenya, this involves evaluating environmental, economic, and logistical factors that suit the specific needs of ornamental plants like roses, bougainvillea, and cacti. Proper site selection minimizes plant stress, reduces pest and disease outbreaks, and enhances efficient resource use, which is essential for sustainable nursery operations.

1.1.1 Definition of ornamental plants

Ornamental plants are cultivated primarily for decorative purposes in gardens, landscapes, and interiors rather than for food or raw materials. They include a wide range of species such as flowering plants, foliage plants, shrubs, trees, and succulents, valued for their aesthetic appeal. Example: a nursery that raises roses, ferns, and aloes for sale to home gardeners and landscapers is producing ornamental plants.

Characteristics of ornamental plants

• Visual Appeal: Ornamental plants are selected for their flowers, foliage, shape, and colour, which contribute to aesthetic enhancement in homes, offices, and public spaces.
• Diverse Species: This group includes both indigenous and exotic species adapted to various climates, requiring specialized propagation and care.
• Non-Consumptive Use: Unlike food crops, they are grown mainly for beautification, cultural significance, or environmental benefits like air purification.
• Propagation Methods: Ornamental plants are propagated sexually (seeds) and asexually (cuttings, grafting, layering, splits, suckers) depending on species and desired traits.
• Economic Importance: The floriculture industry in Kenya generates significant revenue through domestic sales and exports, especially from ornamental plants like roses and chrysanthemums.

1.1.2 Importance of nursery site selection

A nursery stays on its site for many years, and the plants, beds, water systems, and structures built there are costly to move. Choosing the right site therefore ensures that the environment supports the growth requirements of ornamental plants from the start. Careful questioning before establishment helps predict challenges and resource needs, reducing operational risks. Example: a grower who checks water supply and drainage before planting avoids losing a whole batch of seedlings to waterlogging or drought later.

Key reasons for nursery site selection

• Environmental Suitability: Understanding soil, climate, and water availability ensures the site can sustain healthy plant growth.
• Resource Accessibility: Proximity to water sources, labour, and transport infrastructure affects operational efficiency and costs.
• Pest and Disease Risk: Assessing surrounding vegetation and previous land use helps anticipate pest and disease pressures.
• Economic Viability: Financial considerations like land cost, potential for expansion, and market access are critical for long-term sustainability.
• Regulatory Compliance: Checking local land-use rules, environmental requirements, and permits that apply to the area ensures legal conformity and avoids future disputes.

1.1.3 Factors considered when siting a nursery

Selecting a nursery site involves evaluating multiple factors that influence plant health and nursery productivity. These factors must be balanced to create an environment conducive to the growth of various ornamental species. A site that is excellent for one factor, such as a nearby market, may still fail if it has poor water or drainage.

Environmental factors

• Soil Quality: The soil should be well-drained, fertile, and have suitable pH (usually between 5.5 and 7.5) to support root development and nutrient uptake. Example: a nursery on heavy clay soil may need organic matter and coarse sand added to improve drainage before seedlings are raised.
• Water Availability and Quality: Reliable access to clean water is vital for irrigation. Water with high salinity or contaminants can harm delicate ornamental plants.
• Climate Conditions: Temperature, humidity, and sunlight exposure must match the needs of the plants. Shade-loving plants like ferns require different microclimates compared to sun-loving species such as hibiscus.
• Topography and Drainage: A level or gently sloping site prevents waterlogging, which can cause root rot. Adequate drainage systems are essential to remove excess water during heavy rains.
• Wind Protection: Strong winds can damage plants physically and increase transpiration rates. Natural or artificial windbreaks such as hedges or shade nets are often incorporated.

Socioeconomic and logistical factors

• Accessibility: Proximity to markets, suppliers, and transport routes reduces post-harvest losses and transportation costs.
• Labour Availability: The site should be near a workforce skilled or trainable in nursery management.
• Security: Protection from theft and vandalism is important, especially for high-value ornamental plants.
• Cost and Land Tenure: Land should be affordable with clear ownership or lease agreements to avoid future disputes.
• Expansion Potential: Availability of additional land facilitates nursery growth as demand increases.

1.1.4 Tools, equipment and materials used

Efficient nursery operations depend on proper tools and planting materials. On a new site, hand tools are used first to clear vegetation, take soil samples, and level the ground, while seeds, splits, and suckers are the materials from which new plants are raised. Knowing the specification and use of each item ensures quality production and safe working.

Additional nursery tools and equipment

Besides the hand tools used to clear and assess a site, a working nursery needs equipment for propagating, mixing media, watering, and protecting plants.

• Pruning shears: These require regular sharpening and cleaning to prevent disease transmission.
• Propagation trays: These must be sterilised before reuse to avoid fungal contamination.
• Watering cans: These should be handled carefully to prevent damage to seedlings.
• Soil mixers: These improve uniformity in growing media, which enhances root growth.
• Shade nets: These need to be inspected for tears and replaced periodically to maintain effective shading.

1.1.4.1 Panga

The panga is a broad, heavy-bladed cutting tool used to cut thicker material that a slasher cannot manage. When assessing a possible nursery site, it is used to open paths through bushes and remove woody regrowth so that the land can be inspected. Example: a worker uses a panga to cut small trees and shrubs along the boundary where a windbreak will later be planted.

• Sharpening: Keep the blade sharp with a file, as a blunt panga needs more force and slips easily.
• Safe handling: Swing away from the body and legs, and keep other workers at least a few metres away.
• Cleaning: Wipe off sap and soil after use to prevent rust and the spread of diseases.
• Storage: Store with the blade covered or hung on a rack, never left lying in grass.
• Protective wear: Wear gloves and sturdy closed shoes when cutting.

1.1.4.2 Jembe

The jembe is a hand hoe with a flat steel blade, used for digging and loosening soil. During site selection it is used to dig test pits that show soil depth, texture, and drainage. Example: digging a pit about 50 cm deep on a proposed site reveals whether the soil is loose and well drained or compacted and waterlogged.

• Digging: Use it to loosen the topsoil and break large clods.
• Weeding: Cut weeds at the root with the blade edge.
• Handle check: Make sure the blade is firmly fixed to the handle before use.
• Cleaning: Scrape off soil after use and dry the blade to prevent rust.
• Posture: Keep the back straight and bend the knees to reduce strain during long digging.

1.1.4.3 Slashers

A slasher is a long-handled cutting tool with a curved or straight blade, used to cut grass and soft weeds quickly. At a prospective nursery site it clears the ground cover so that the slope, stones, and soil surface can be seen. Example: before measuring the plot, a worker slashes the tall grass in a swinging motion close to the ground.

• Cutting action: Use a sweeping, side-to-side motion at ground level.
• Working space: Keep a clear distance from other workers while slashing.
• Sharpening: A sharp blade cuts cleanly and reduces fatigue.
• Inspection: Check for cracks in the blade and a loose handle before each use.
• Protective wear: Wear gloves, boots, and long trousers, as stones and snakes may be hidden in the grass.

1.1.4.4 Rake

A rake has metal tines fixed to a long handle and is used to gather cut vegetation, stones, and other debris and to level loose soil. In the early stage of a nursery it helps to tidy the cleared plot and to give a smooth surface for marking out. Example: after slashing, a worker rakes the cut grass into heaps for removal from the site.

• Gathering: Pull debris toward the body in short strokes.
• Levelling: Use the back of the rake head to smooth soil surfaces.
• Tine check: Replace bent or broken tines, as they leave uneven ground.
• Cleaning: Remove soil and plant material after use.
• Storage: Hang the rake with the tines facing the wall, or lay it with the tines down, to prevent injuries.

1.1.4.5 Seeds

Seeds are the product of sexual reproduction and are one of the main planting materials in an ornamental nursery. They are used for species such as marigold, cosmos, and many annual bedding plants, and they allow many plants to be raised cheaply. Example: a nursery sows a packet of marigold seeds in trays to produce hundreds of seedlings for sale.

• Source: Collect or buy from healthy parent plants or reputable suppliers.
• Viability: Choose fresh seed with a good germination rate, as old seed germinates poorly.
• Cleanliness: Seeds should be free from pests, moulds, and damage.
• Labelling: Label each lot with the species, variety, and date of collection or purchase.
• Storage: Keep dry, cool, and in labelled airtight containers away from rodents.

1.1.4.6 Splits

Splits are sections of a mature clump that are separated, each with its own roots and shoots, and planted as new individuals. This is an asexual method used for clump-forming ornamentals such as agapanthus and canna lilies. Example: an overgrown agapanthus clump is dug up and divided into several pieces, each with a healthy root portion and leaves.

• Parent plant: Use a healthy, mature clump free from pests and disease.
• Division: Cut or pull the clump apart with a clean, sharp tool so that each piece keeps roots and shoots.
• Size: Each split should be large enough to establish quickly.
• Trimming: Remove dead or damaged roots and leaves before planting.
• Timing: Plant immediately, or keep in shade and moist, to prevent drying out.

1.1.4.7 Suckers

Suckers are shoots that grow from the roots or the base of a parent plant, and they often develop their own roots while still attached. They can be cut away and planted as new plants that are identical to the parent. Example: a sucker of a cordyline is cut cleanly from the base of the mother plant with some roots and potted into a moist rooting medium.

• Selection: Choose vigorous suckers of reasonable size, with some roots already present.
• Separation: Cut cleanly between the sucker and the parent without damaging either.
• Tool hygiene: Disinfect the cutting tool to avoid transferring diseases.
• Handling: Keep the roots moist and protected from sun and wind.
• Aftercare: Plant promptly in a prepared medium and keep shaded until new growth appears.

Chapter Summary

This chapter explored the preparation of planting materials for ornamental plants starting with the critical task of nursery site selection, highlighting the definition of ornamental plants and the key questions to consider when choosing a suitable location. It outlined the essential factors that influence nursery site selection such as soil quality and water availability, and described the tools, equipment, and materials commonly used including pangas, jembes, slashers, rakes, seeds, splits, and suckers. The process of nursery preparation was detailed to ensure optimal conditions for seed germination and plant growth. Techniques for planting seeds in the nursery were explained alongside crucial nursery management practices such as mulching, shading, hardening off, watering, fertilizer application, pest and disease control, and pricking out to promote healthy seedlings. The chapter also covered practical steps for preparing nursery beds and carrying out planting operations effectively. Finally, it emphasized the importance of consistent nursery bed management practices to maintain plant health and maximize ornamental plant production success.