Although not specifically about planting or growing, the traffic to my hub about getting a lawn mower started starts to grow around March, with peaks on Saturdays on Sundays as poor unfortunates run into problems getting their machine started. (Its fun watching Google analytics in realtime mode as the search queries come in!) During the winter in the northern hemisphere, traffic drops to less than 10 views per day. Now the population of Australia and New Zealand combined is only 27 million according to Wikipedia, whereas that of the US is 315 million, Canada 33 million and the UK 63 million. English is the official but not the primary language of some southern African countries also. So the audience of native English speakersin the southern hemisphere is much smaller and presumably this influences traffic during winter in the northern hemisphere.