Module 1: Introduction to Greenhouses

Groundwork to Grow is a collection of 4-week workshops offered by Hoʻōla Farms on various agriculture topics, offering exposure to community resources, local experts and experienced farmers. This course covers an introduction to Greenhouses.

Future Groundwork to Grow Courses:

• Value-Add Products
• Beekeeping – October 2022!
• Agroforestry
• Orchards

Schedule:

• Tuesdays: Virtual Meeting – 5:30-7:00pm
  • 8/2, 8/9, 8/16, 8/23
• Saturdays: Field Day – 8:00am-12:00pm
  • 8/6, 8/13, 8/20, 8/27

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Before we delve into the details of greenhouses and their many different styles and variations, it is important to first establish what your goals are, and what your resources are. This will help determine what direction you take and what type of structure you will want to focus on building.

Introductions:

• Name
• Where do you live
• What is your experience with greenhouses?
• Why are you taking this course?
• What are your greenhouse goals?

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What is a Greenhouse?

Brittanica definition: greenhouse, also called glasshouse, building designed for the protection of tender or out-of-season plants against excessive cold or heat.

Oxford definition: A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of transparent material, such as glass, in which plants requiring regulated climatic conditions are grown.

What is the greenhouse effect?

When energy from the Sun goes through Earth’s atmosphere and warms the planet’s surface, but the atmosphere prevents the heat from returning directly to space, resulting in a warmer planet.

What are greenhouse gases? What do they cause…?

• A gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect.
• Primary greenhouse gases in Earth’s atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3)

History

• The second Roman Emperor Tiberius, reigned from AD 14 until 37 wanted a cucumber-like fruit at every meal.
• Korea – first description of heated greenhouse – 1450s under Joseon dynasty using ondol: an underfloor heating technique.

Why use a greenhouse?

Because you want to change the climate for your plants.

1. Protection from excess rain
2. Protection from pests
3. Higher air temperatures (for higher elevations)

• Unique Benefits of Greenhouses for Vegetable Production in Hawai’i (1970s!)
• Eight Different Styles of Greenhouse
• Hoop House vs High Tunnel

Kratky Method

• A passive hydroponic system developed by Dr Bernard Kratky, from UH Hilo.

• https://www.ctahr.hawaii.edu/hawaii/downloads/three_non-circulating_hydroponic_methods_for_growing_lettuce.pdf
• https://university.upstartfarmers.com/blog/kratky-method
• https://www.bobvila.com/articles/kratky-method/

Kratky videos:

The Man Himself! – https://www.youtube.com/channel/UCjwBvl5MXuQMziQL2_pQCPA

MIgardener – https://www.youtube.com/watch?v=NqBcN4kek-c