Establishing a sub-tropical fruits nursery is a critical step in the horticultural production chain that ensures healthy and vigorous planting materials for commercial orchards. In Kenya, where sub-tropical fruits such as avocados, mangoes, and guavas are increasingly important both for local consumption and export, the nursery serves as the foundation for sustainable fruit production. Proper nursery establishment involves understanding the environmental requirements, selecting quality planting materials, and implementing best practices for pest management and propagation. This chapter focuses on essential preparatory measures, starting with the use of personal protective equipment and defining key terms related to sub-tropical fruits.

1.1 Personal protective equipment

Nursery work exposes workers to pesticides, fertilisers, sharp tools, thorns, soil-borne organisms, dust and the sun. Personal protective equipment (PPE) is the clothing and gear worn to create a barrier between the worker and these hazards. In a sub-tropical fruit nursery PPE is needed during pesticide spraying, grafting and pruning, mixing potting media and handling fertilisers. It also protects the planting material, because clean gloves and clothing reduce the spread of diseases between seedlings. The Occupational Safety and Health Act, 2007 requires employers to provide suitable PPE and workers to use it.

Example: a county fruit tree nursery in Embu issues each worker with gloves, overalls and gumboots, and keeps respirators and goggles in a locked store for the person who sprays fungicides.

Types of PPE used in the nursery

• Gloves: Protect hands from cuts, thorns, chemicals and infections during soil handling, grafting and pesticide application. Nitrile gloves are used for chemicals and leather or cotton gloves for rough work.

Pair of yellow work gloves used in carpentry (Source: Wikimedia Commons)

• Respirators or masks: Prevent inhalation of dust, spores and chemical fumes, especially when spraying fungicides or insecticides.
• Protective clothing: Overalls, dust coats or waterproof aprons shield the skin from chemical splashes, sap and dirt.
• Eye protection: Goggles or face shields protect the eyes from chemical splashes and flying debris when pruning.
• Footwear: Gumboots or safety boots protect feet from sharp objects, wet ground and chemical spills.
• Sun hat: A wide-brimmed hat protects against sunburn and heat stress during long hours in open beds.

Importance of using PPE in the nursery

• Health protection: Reduces chemical poisoning, skin and eye irritation, respiratory problems and injuries.
• Productivity: Healthy workers lose fewer days to illness and injury.
• Quality of seedlings: Clean PPE reduces contamination of planting material, helping produce disease-free seedlings.
• Legal compliance: Meets the requirements of the Occupational Safety and Health Act and pesticide label instructions.
• Environmental safety: Proper handling reduces accidental spills and contamination.

Selection and proper use of PPE

• Task assessment: Identify the hazards of each job; spraying needs a full suit, respirator, gloves and boots, while grafting may need only gloves and eye protection.
• Quality: Use PPE that meets Kenyan or international safety standards and the pesticide label.
• Fit and comfort: Ill-fitting PPE is uncomfortable and workers stop wearing it.
• Correct wearing: Trouser legs go over boots and sleeves over gloves so that chemicals run off, not in.
• Training: Train workers regularly on correct use, limits and disposal of PPE.

Maintenance and disposal of PPE

• Cleaning: Wash reusable PPE such as gloves and overalls after each use, separately from household laundry.
• Inspection: Check for tears, holes and worn parts before and after use.
• Repair or replacement: Replace damaged PPE and respirator filters at once.
• Storage: Store PPE in a clean, dry place away from sunlight and away from the chemical store.
• Disposal: Dispose of single-use and heavily contaminated items as hazardous waste following NEMA guidelines.

Definition of terms

The following terms are used throughout this unit. Knowing them helps nursery workers follow instructions and communicate clearly with buyers and extension officers.

Sub-tropical fruits

Sub-tropical fruits are fruit crops that grow best in warm climates with mild, frost-free cool seasons, between the true tropics and the temperate zones. In Kenya they do well in the medium to high altitude areas (about 1,000 to 2,400 m above sea level), such as the central highlands, the Rift Valley and parts of the western region.

• Temperature: Grow best at about 15 to 30 °C; damaged by frost.
• Rainfall: Need about 700 to 1,500 mm a year, well distributed, or irrigation.
• Growth habit: Mostly evergreen trees or shrubs, though some, such as strawberry, are small herbaceous plants.
• Soils: Prefer deep, well-drained, fertile soils rich in organic matter.
• Economic value: In demand in local and export markets for fresh fruit, juice and processing.

Tree tomatoes

The tree tomato (tamarillo, Solanum betaceum) is a fast-growing, short-lived shrub 2 to 4 m tall, grown in the cool highlands of Kenya. It bears oval red or yellow fruits used fresh and for juice. It is propagated by seed or cuttings and starts fruiting about 18 months after planting.

Strawberry

Strawberry (Fragaria × ananassa) is a low-growing perennial herb grown in the cool highlands for fresh fruit, jam and yoghurt flavouring. It is propagated mainly from runners (daughter plants) raised in the nursery, and needs well-drained, slightly acidic soil, mulching and regular watering.

Guava

Guava (Psidium guajava) is a hardy small tree that grows from the coast to the highlands. Its fruits are rich in vitamin C and used fresh and for juice and jam. It can be raised from seed but improved varieties are propagated by grafting, budding, layering or cuttings.

Loquat

Loquat (Eriobotrya japonica) is an evergreen tree with large leathery leaves that bears clusters of small yellow-orange fruits in the cool season. It grows well in the highlands and is propagated by seed for rootstocks and by grafting for named varieties.

Lime

Lime (Citrus aurantiifolia and related species) is a citrus tree producing small, acidic green fruits used for juice, flavouring and drinks. It grows best in warm lowland and mid-altitude areas and is propagated by budding onto rootstocks such as rough lemon in the nursery.

Propagation terms

• Seedling: A young plant raised from seed, which may differ from its parent.
• Rootstock: The lower part of a grafted plant that provides the root system.
• Scion: The shoot or bud of the desired variety joined onto the rootstock.
• Grafting: Joining a scion onto a rootstock so that they grow as one plant.
• Budding: A form of grafting in which a single bud is inserted under the bark of the rootstock.
• Marcotting (air layering): Rooting a branch while it is still attached to the parent plant, then cutting it off.
• Tissue culture: Laboratory propagation from small pieces of plant tissue to produce many uniform, disease-free plants.

Growth stage terms

• Germination: The sprouting of a seed and emergence of the young root and shoot.
• Seedling stage: The young plant develops true leaves and roots and needs careful watering and shade.
• Vegetative growth: The period of leaf, stem and root growth before flowering.
• Flowering: Formation and opening of flowers, leading to fruit set.
• Fruiting: Development and ripening of the fruits.

Pest and disease terms

• Infestation: The presence of pests such as aphids or mites on plants in numbers that cause damage.
• Infection: The entry and establishment of a pathogen (fungus, bacterium or virus) in a plant, leading to disease.
• Vector: An organism, usually an insect, that carries a pathogen from one plant to another.
• Resistance: The ability of a variety or rootstock to withstand a pest or disease.
• Quarantine: Isolation of plant material to prevent the spread of pests and diseases to healthy stock.

Chapter Summary

This chapter introduced the essential personal protective equipment required for safely handling sub-tropical fruit nursery operations and clarified key terms related to sub-tropical fruits. It emphasized the importance of selecting an appropriate nursery site by considering factors such as climate, accessibility, and water availability. The chapter detailed the process of conducting soil analysis at the nursery site to ensure optimal soil conditions for healthy plant growth. It also covered the selection and maintenance of essential nursery tools necessary for efficient operations. Preparation of the nursery site was discussed, including land clearing and bed formation to create a suitable environment for planting. Techniques for raising planting materials in the nursery were explained, highlighting propagation methods and seedling care. Finally, the chapter addressed routine agronomic practices, including watering, fertilization, and the control of pests and diseases to maintain healthy nursery stock.