15th October 2014

Lecture day

We looked at the technical details and structure of different greenhouses today. Unfortunately contractors who were hired to clean the outside of The Glasshouse broke one of the panes of glass yesterday, so have to replace it. An expensive mistake, but we had the rare opportunity to witness them installing a new one in (Photo 1). 

Photo 1: Five men replacing a pane of The Glasshouse.

Photo 2: Wisley Propagation house 1-3 - Multi-span Houses. Characteristics - continuous ridge vents, galvanised steel open channelled guttering, trusses (the triangular bar structures), purlins - metal pieces that runs the length of the greenhouse and keeps the roof trusses aligned. There are lateral ventilators too on most outer walls of the houses. They are used in high quality plant production. Disadvantage - overlapping windows, harder to clean and 'gaps' harbour diseases etc.

Photo 3: An old dutch light glasshouse c1960 made of metal and glass (with shade paint). An evolution of dutch light cold frames. Beautiful and great as a historical piece now, but not so practical, e.g sloping sides do not give much headroom, wood doesn't lock together as well as metal and loses a lot of heat easily.

After this we looked at pest & diseases that could possibly occur when we do our allotment. We also learnt or refreshed on the 3-4-5 measuring method based on Pythagoras right triangle, a check to see if a border/ bed is in a straight line, in preparation for when we are assigned our allotment.

Photo 4: Checking if an area is a right angle i.e. if it's straight

 

With here you take numbers a = 3, b = 4, c = 5.