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Greenhouse Horticulture Environment Management and Cultivation

Agriculture · 農業 · Written by Tokutei Pass based on the official study texts; not copied verbatim.

Types of Greenhouse Structures, Covering Materials, and Disaster Prevention

Greenhouse structures include "pipe houses" built from bent steel pipes covered with plastic film, and stronger, more durable "steel-frame greenhouses (including glasshouses)". Roof styles include arched (quonset) and gable roofs.

Covering materials include "glass" with high durability and light transmission, as well as lightweight, easy-to-handle "agricultural polyolefin (PO) film" and "agricultural PVC film". Internal thermal curtains are also used to improve heat retention.

Before typhoons or strong winds, close all roof vents, side vents, and doors, retighten hold-down straps, and repair any torn film. During heavy snowfall, run heaters to melt snow and prevent structural collapse.

Types of Greenhouse Structures, Covering Materials, and Disaster Prevention

Key points


  • Greenhouses include pipe houses and steel-frame houses covered with glass, PO film, or PVC film.

  • Before a typhoon, close all vents and doors completely and check hold-down bands and film tears.

  • Close internal thermal curtains on winter nights to prevent heat loss and improve heating efficiency.
WordMeaning
pipe house / steel-frame greenhouse
covering materials (PO film / PVC film)
internal thermal curtain
roof vent / side vent

Controlling Temperature, Humidity, Light, and CO2 Inside Greenhouses

On sunny days, greenhouse temperatures rise rapidly; prevent heat stress through natural ventilation (opening roof and side vents) or forced ventilation (exhaust fans). In summer, shade nets and fog cooling systems are also used.

Excessive humidity inside the greenhouse encourages diseases like gray mold, so combine ventilation with air circulation fans (circulators) to keep air moving, prevent leaf condensation, and eliminate temperature pockets.

When vents remain closed on winter mornings, plant photosynthesis depletes indoor carbon dioxide (CO2). Supplementing CO2 with a CO2 generator starting around sunrise boosts photosynthesis, increasing yield and quality.

Key points


  • Control daytime high temperatures using ventilation (roof/side vents, exhaust fans) and shade nets.

  • Circulation fans eliminate temperature unevenness and prevent condensation and humidity-related diseases.

  • Applying carbon dioxide (CO2) in the early morning promotes crop photosynthesis.
WordMeaning
natural ventilation / forced ventilation
shade net
air circulation fan (circulator)
photosynthesis / CO2 enrichment

Irrigation Systems, Hydroponics, and Soil Disinfection

Because rain cannot enter a greenhouse, artificial irrigation is essential. Methods include "drip irrigation (drip tubes)" that delivers water and liquid fertilizer slowly to the plant base without raising humidity, and "overhead sprinklers" for leafy crops.

Growing crops without soil using nutrient solution (water with dissolved fertilizers) and media such as rockwool or coco peat is called "hydroponics / nutriculture (youeki saibai)". It avoids soil-borne continuous cropping injury and requires daily monitoring of electrical conductivity (EC, nutrient concentration) and pH.

To control soil-borne pests and diseases in soil-based greenhouses, perform "solarization (taiyounetsu shoudoku)" in summer by flooding the soil, covering it with clear plastic film, and sealing the house to trap solar heat, or use steam sterilization.

Irrigation Systems, Hydroponics, and Soil Disinfection

Key points


  • Drip tube irrigation waters only the root zone and prevents excessive greenhouse humidity.

  • In hydroponics, properly manage the nutrient solution EC (fertilizer concentration) and pH (acidity).

  • Solarization seals the greenhouse in summer to raise soil temperature with solar heat and reduce soil pests and pathogens.
WordMeaning
drip irrigation tube
hydroponics / nutrient solution
EC (electrical conductivity / nutrient concentration)
soil solarization

Managing Greenhouse Fruit Vegetables (Tomatoes, Cucumbers, and Strawberries)

Tomatoes are commonly trained to a single main stem ("single-stem training"), with lateral shoots ("suckers / wakime") pinched out while small. To ensure fruit set inside greenhouses, introduce bumblebees (maruhanabachi) or use hormone sprays or vibration pollination.

In long-term cucumber cultivation, practice "vine-lowering training (tsuruoroshi)", gradually lowering the main stem to keep the growing zone at a comfortable working height, along with "defoliation (tekiyou)" to remove old or diseased lower leaves.

Strawberries are propagated from daughter plants formed on "runners (stolons)" extending from mother plants. When transplanting, keep the "crown" above the soil surface without burying it, and use honeybees inside the greenhouse during flowering to ensure uniform pollination and prevent malformed fruit.

Key points


  • Remove suckers on tomatoes and pollinate flowers using bumblebees, hormone treatment, or vibration.

  • Practice vine lowering (tsuruoroshi) and removal of old lower leaves (tekiyou) in cucumbers.

  • Propagate strawberries from runners, plant without burying the crown, and pollinate with honeybees.
WordMeaning
bumblebee / honeybee
vine-lowering training
runner (stolon)
crown (shortened stem base)

Greenhouse Horticulture

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