1. Greenhouses/Hydroponics
An Iceland Example

2. Friðheimar, Selfoss, Iceland

3. Selfoss, Iceland

5. Friðheimar Greenhouses
They grow:
Tomatoes
Cucumbers
Under artificial lighting and geothermal heating
5000m3+ (55,000 ft3) greenhouses

6. Friðheimar Greenhouses
manage pests using biological controls
predatory mirid bug Macrolophus pygmaeus, which devours all the main pests that afflict tomato plants.
seeds are planted, and the plants grow in pots the first six weeks, with automated watering.
 When the plants are transplanted into the greenhouse they are flowering on the first truss, and seven to eight weeks later the first tomatoes blush red.

7. Friðheimar Greenhouses (cont)
the tomatoes are cultivated in turf, and plants are renewed twice a year.
 the crop takes a long time to reach fruition, a system of interplanting is used:
young plants are planted in between the older plants, and
the two grow side by side for seven to eight weeks.
Just as the last tomatoes are ready to pick on the older plants, the first tomatoes on the young plants are turning red.

8. Friðheimar Greenhouses (cont)
The farm has abundant supplies of geothermal water, which provides heat to the greenhouses.
The borehole is 200 m from the greenhouses and the water flows into them at about 95°C / 203°F.  
In order to maximize sunlight in the greenhouses, the glass panes are only 4 mm thick,
so a huge amount of hot water is needed –
about 100,000 tons per year!
The pure cold water used for irrigation is from the same source as the family’s own water supply.

9. Friðheimar Greenhouses (cont)
Since tomatoes are about 90% water, the quality of irrigation water is very important.
Iceland has abundant resources of “green” electricity from hydro and geothermal power plants, providing the artificial lighting necessary to grow the crops all year round at such a northerly latitude.
Photosynthesis is enhanced by using carbon dioxide produced from natural geothermal steam. 

11. Modern Technology
Each greenhouse is equipped with a climate-control computer system for:
temperature,
humidity,
carbon dioxide and
lighting.
The computer is connected with a fertilizer mixer, which waters the crop according to a programmed system.
On the roof a weather observation unit provides data on:
wind speed and direction,
temperature and
light.

12. Modern Technology (cont)
When the sun comes out, and natural light reaches a certain level, the lights are automatically switched off – and come on again when the light level falls.
All the systems are linked into a computer connected to the internet –  so Knútur and Helena can monitor and adjust the systems at Friðheimar, wherever they are in the world.