This post is part of the series Simulating Climates in Growth Chambers.
Day length for a given latitude can be obtained from online programs, such as the online photoperiod calculator at http://www.sci.fi/~benefon/sol.html Day length was reprogrammed weekly for convenience. Latitude can be chosen corresponding to a target location (e.g., Williams Lake, 52°07’N) or latitude representative of an area, e.g. the province of B.C. (54.5°N).
Some practical limitations may rise here. Until LED lights become cheaper still, any light source also generates heat. It may not be possible to program a sunrise while temperatures are still below 4°C. This depends on the hardware of the climate chamber. In this case, consider turning on the lights gradually, reducing light intensity, and leaving off any incandescent lights until later, as they generate a relatively high percentage of heat.
Next up on the list is simulating winter conditions, heat waves, stimulating germination and bud set. You can also go back through some of our older posts on simulating climates in growth chambers.