Establishing a nursery for cut flowers is a foundational step in ensuring the successful production of high-quality blooms. In Kenya, where floriculture is a significant contributor to the horticultural sector and export earnings, the choice of nursery location and setup directly impacts plant health, growth rates, and ultimately market competitiveness. This chapter guides horticulture professionals through the critical aspects of nursery site selection, highlighting the practical considerations and tools necessary to optimize nursery performance.

1.1 Nursery Site Selection

Selecting an appropriate site for a cut flower nursery is a complex decision requiring understanding of the biological needs of cut flowers and environmental factors. The nursery site influences water availability, pest and disease pressure, and ease of management, all of which affect the quality and quantity of flower production. In Kenya, where climatic zones vary widely from the highlands to arid areas, site selection must be strategic to align with the specific requirements of the flower species being propagated.

1.1.1 Definition of cut flowers

Cut flowers are horticultural plants grown primarily for their blooms, which are harvested and sold as detached stems for decorative use. Unlike flowering plants grown for landscaping or garden beautification, cut flowers are cultivated to meet market demands for freshness, size, colour, and vase life. Examples include roses, carnations, statice, and alstroemeria, many of which are raised in nurseries before transplanting to production fields or greenhouses.

Characteristics of cut flowers

• Detachment at harvest: Cut flowers are harvested by severing the flower stem from the plant, requiring stems of adequate length and strength to support the bloom.
• High quality standards: They must exhibit visual appeal, including vibrant colour and absence of blemishes, to satisfy consumer preferences in both local and international markets.
• Short shelf life: Cut flowers have a limited post-harvest lifespan, necessitating careful handling from nursery to consumer to maintain freshness.
• Specific growing conditions: Each species has unique requirements for temperature, humidity, and soil conditions, influencing nursery management practices.
• Economic value: Cut flowers are an export commodity for Kenya, contributing to foreign exchange earnings and to employment in rural areas.

Differentiation from other ornamental plants

Cut flowers differ from potted flowering plants or foliage plants in that their commercial value depends on the harvested flower quality and durability rather than the longevity of the whole plant. This distinction influences propagation techniques, nursery layout, and care practices.

1.1.2 Importance of nursery site selection

The nursery is where every future flower plant begins its life, so a poor site creates problems that follow the crop right through to harvest. A nursery sited in a low, waterlogged hollow, for example, is likely to suffer seedling losses from damping-off, while one far from a water source will have high watering costs. Asking the right questions before any land is cleared helps identify constraints and opportunities, and shapes management decisions that influence productivity and profitability.

Key reasons for careful site selection

• Optimising environmental suitability: Understanding local climate, soil, and water resources ensures that the site supports healthy plant growth and reduces the risk of crop failure.
• Cost efficiency: Proper site selection reduces the need for expensive inputs such as irrigation infrastructure or soil amendments, lowering operating costs.
• Pest and disease management: Sites with poor drainage or proximity to infected crops increase vulnerability to pests and diseases, affecting flower quality.
• Accessibility and logistics: Good transport access and proximity to markets shorten post-harvest handling and delivery times, which is critical for maintaining flower freshness.
• Regulatory compliance: Considering zoning laws and environmental regulations during site selection prevents future legal complications.

Examples of site selection questions

• Is the soil suitable for the specific cut flower species intended for production?
• What is the availability and reliability of irrigation water sources?
• Does the site have adequate sunlight exposure throughout the day?
• Are there any nearby sources of pollution or pest infestation?
• How accessible is the site for labour, inputs delivery, and product transport?

1.1.3 Factors considered when siting a nursery

Choosing a nursery site requires evaluating multiple environmental, economic, and social factors to create optimal conditions for cut flower propagation and growth. Each factor influences plant performance and operational efficiency, demanding a holistic assessment. For example, a site with excellent soil but no reliable water in the dry season may still be unsuitable for a rose or carnation nursery.

Climatic factors

• Temperature range: Cut flowers such as roses thrive in moderate temperatures (18°C to 24°C). Sites with extreme heat or cold require additional climate control measures, increasing costs.
• Sunlight intensity and duration: Adequate sunlight is essential for photosynthesis and flower development. Sites should receive at least 6 hours of direct sunlight daily.
• Rainfall patterns: While rainfall can reduce irrigation needs, excessive rain may cause waterlogging and fungal diseases. Drainage planning is critical in high rainfall areas.
• Wind exposure: Strong winds damage tender seedlings, tear shade netting and dry out beds. Where wind is a problem, a windbreak of trees or a hedge on the windward side gives shelter.
• Frost and hail risk: Sites prone to frost pockets or hail can lose whole seedling batches, so low-lying cold hollows should be avoided.

Soil characteristics

• Soil texture and structure: Loamy soils with good aeration and water retention are ideal for nursery beds, supporting root development.
• Soil pH: Most cut flowers prefer slightly acidic to neutral soils (pH 6.0 to 7.0). Soil testing guides lime or sulphur application to adjust pH accordingly.
• Nutrient content: Fertile soils rich in organic matter enhance seedling vigour, reducing reliance on synthetic fertilisers.
• Drainage: Well-drained soils prevent root rot and other moisture-related diseases, crucial in nursery environments.
• Soil-borne pest and disease history: Land previously under crops that suffered nematodes or wilts may carry these problems into the nursery, so the cropping history of the land should be checked.

Water availability and quality

• Source reliability: Permanent water sources such as boreholes or rivers ensure consistent irrigation, vital during dry seasons.
• Water quality: Water should be free from contaminants such as salts and heavy metals that can accumulate in soil and harm plants.
• Irrigation infrastructure: The site must accommodate efficient irrigation systems such as drip or overhead sprinklers.
• Distance to the water source: A nursery close to its water source needs shorter pipes and less pumping or carrying, which lowers labour and energy costs.
• Water storage potential: Space for a tank or small reservoir gives a buffer when supply is interrupted.

Topography and land features

• Gentle slope: A slight, even slope of about 1 to 3 percent allows excess water to drain away without causing erosion. Steep slopes need terracing, while flat, low ground collects water.
• Aspect: Beds facing the morning sun dry quickly and receive good light, which reduces fungal problems.
• Size and shape of the plot: The land must be large enough for beds, paths, a propagation area, a store and room for future expansion.
• Cleared or easily cleared land: Sites with heavy bush, stumps or rocks cost more to clear and prepare, which should be weighed against other advantages.

Accessibility and infrastructure

• Transport links: Proximity to major roads facilitates timely delivery of inputs and shipment of cut flowers to markets or processing centres.
• Labour availability: Sites near communities with skilled horticultural labour reduce recruitment challenges.
• Utilities: Availability of electricity supports greenhouse operations and equipment use.
• Security: A site that can be fenced and supervised protects young plants, tools and inputs from theft and from browsing animals.
• Isolation from pest sources: The nursery should be away from older flower crops with heavy pest or disease pressure and from places where chemicals are sprayed heavily, to reduce infection and spray drift.

Environmental and regulatory considerations

• Environmental impact: Sites should avoid ecologically sensitive areas, such as riverbanks and wetlands, to comply with Kenya's environmental laws and protect biodiversity.
• Zoning and land use: Confirming land use permits and restrictions prevents conflicts with local authorities or neighbouring landowners.
• Land tenure: Secure ownership or a long enough lease justifies the investment in beds, shade structures and irrigation.

1.1.4 Tools, equipment and materials used

A cut flower nursery requires specialised tools and equipment to facilitate site clearing, propagation, maintenance, and management activities, together with the planting materials from which new plants are raised. Proper selection and use of these items improve efficiency and plant quality. The table below lists the main tools and equipment, and the planting materials are described afterwards.

Usage and maintenance of general nursery tools

• Propagation trays should be cleaned and disinfected after each use to prevent disease spread.
• Pruning shears require regular sharpening and oiling to maintain clean cuts, reducing plant damage.
• Watering cans must be emptied and stored indoors to prevent algae growth and contamination.
• Soil testing kits need calibration according to manufacturer instructions to ensure accurate readings.
• Shade nets should be inspected for tears and properly secured to withstand wind.
• Hand trowels should be cleaned after use and stored in dry conditions to avoid rust.
• Sprayers must be rinsed thoroughly after chemical application and maintained to prevent clogging.

1.1.4.1 Panga

A panga is a heavy, broad-bladed cutting tool made of carbon steel, used in the early stages of establishing a nursery. During site preparation, a worker uses it to cut shrubs, saplings and thick woody growth, and to cut stakes and poles for the shade net frame and fence. Its weight gives enough force to cut woody stems that a slasher cannot manage.

• Safe use: Cut away from the body, keep bystanders at a safe distance, and wear boots and gloves.
• Care: Sharpen the blade with a file, wipe it clean and dry after use, lightly oil it, and keep it in a sheath or on a rack.

1.1.4.2 Jembe

A jembe is a hand hoe with a flat, forged steel blade fixed to a long wooden handle. In a flower nursery it is used to dig, break soil clods, level the ground and open drainage channels that carry excess water away from the beds. It is also used to uproot weeds and their roots in cleared ground.

• Safe use: Keep a firm stance, strike with controlled swings, and make sure the blade is tightly fixed to the handle.
• Care: Scrape off soil after use, wash and dry the blade to prevent rust, and store it with the blade down or hung on a rack.

1.1.4.3 Slashers

A slasher is a long-handled cutting tool with a curved or straight steel blade, used to cut grass and soft weeds with a sweeping motion. In nursery work it clears the vegetation on the chosen site and keeps the perimeter short, which removes hiding places for rodents, snakes and insect pests. It is lighter and faster than a panga for soft growth but unsuitable for thick woody stems.

• Safe use: Swing in a clear arc with enough space around, wear boots and eye protection, and never swing towards other workers.
• Care: Keep the blade sharp with a file, clean off sap and soil after use, and oil the blade before storing.

1.1.4.4 Rake

A rake is a long-handled tool with a steel head carrying short tines. Once the site is cleared and dug, it is used to gather and remove stones, roots, dry grass and other debris, and to level the ground. In nursery work it also leaves a smooth, even surface on which beds can later be formed.

• Safe use: Work with the tines facing down, and never leave a rake lying with the tines facing up where someone could step on it.
• Care: Remove soil and plant material from between the tines, wash and dry the head, and hang it up after use.

1.1.4.5 Seeds

Seeds are the product of sexual reproduction and are one of the main planting materials in a cut flower nursery. Species such as statice are commonly raised from seed, which is cheap, easy to store and transport, and allows many plants to be raised in a small space. Seed quality decides how evenly seedlings emerge, so the nursery manager must choose carefully.

• Source: Buy from a reputable supplier and check the variety, purity, germination percentage and expiry date on the label.
• Viability: Fresh, plump seed that has been stored dry and cool germinates better than old or damp seed.
• Uniformity: Seed of a known variety gives plants of similar height, colour and flowering time, which buyers need.
• Storage: Keep seed in sealed, labelled containers in a cool, dry and shaded store away from rodents and insects.
• Health: Seed should be free from disease and pest damage, since problems carried in seed spread to the whole seedbed.

1.1.4.6 Splits

Splits are pieces of a mature plant, each with roots and at least one shoot or growing point, obtained by dividing a clump or crown. This is a form of vegetative propagation that gives plants identical to the mother plant. It is used for flowers that form clumps or spreading rhizomes, such as alstroemeria and gerbera.

• Selection of mother plants: Choose vigorous, healthy, true-to-type clumps free from pests and viral symptoms.
• Dividing: Lift the clump carefully and separate it by hand or with a clean, sharp knife, so that each split keeps healthy roots and shoots.
• Preparation: Trim damaged roots and shoots, and remove diseased tissue before planting.
• Handling: Keep splits shaded and moist, and plant them soon after division so that they do not dry out.
• Hygiene: Disinfect the knife between clumps to avoid spreading disease.

1.1.4.7 Suckers

Suckers are shoots that arise from the base or underground parts of a mother plant, often with their own roots, and can be separated to form new plants. Chrysanthemum stools, for example, send up basal suckers after the flowers are cut, and these are removed and rooted to produce new plants. Suckers give plants true to the mother plant and flower earlier than plants grown from seed.

• Selection: Take suckers from healthy, productive mother plants that show no signs of pests, diseases or virus infection.
• Size: Choose suckers that are well developed, with some roots or a good base, and not weak or spindly.
• Separation: Detach each sucker cleanly with a sharp, disinfected knife or by careful digging, without damaging the mother plant.
• Handling: Keep the suckers cool, shaded and moist after removal, and plant them without delay.
• Mother plant care: Water and feed the mother plants after sucker removal so that they recover and continue to produce.

Chapter Summary

This chapter covers the establishment of a cut flowers nursery, beginning with the definition of cut flowers and the critical importance of selecting an appropriate nursery site. It explores the various factors that influence site selection, including climate, soil quality, and accessibility, alongside the essential tools, equipment, and planting materials such as pangas, jembes, slashers, rakes, seeds, splits, and suckers. The preparation of the nursery is detailed to ensure optimal growing conditions before planting seeds, which requires careful attention to spacing and soil management. Effective nursery management practices are emphasized, including mulching to retain moisture, shading to protect young plants, hardening off seedlings to prepare them for transplanting, regular watering, appropriate fertilizer application, pest and disease control, and pricking out to manage seedling growth. The chapter also guides practical skills in nursery bed preparation and planting, followed by ongoing nursery bed management to sustain healthy plant development. These integrated steps provide a comprehensive foundation for successful cut flower production from nursery establishment to maintenance.