Thought this might be of interest to some.
T sum 200 is a measured used in agriculture to indicated when the ground is ready to start receiving fertilizer. It is worked out from the start of January, measuring the mean daily air temp, adding them together each day until 200 is reached. When T sum 200 is reached it is the trigger point for applying fertilizer.
For the farmer this is key as any fertilizer application prior to T Sum 200 is likely to result in leaching of nutrient before the plant is active enough to take them up..
If you look at the link below you will see that most of the UK has reached T sum 200. Click on the square that relates to you and you will see some more detailed information:
http://www.fwi.co.uk/default.asp?hier=210&sec=156
Obviously this is a broad measure and only an indication. It does not take into effect local micro climates or soil conditions.
Still I always think that when T sum 200 is reached we know we are getting close to the real spring.
Jerry
It's certainly more scientific, but doesn't quite have the charm of dropping your trousers and putting your bare bum on the ground! ;D Or was that for sowing rather than fertilizing?
Might as well fertilise while you're down there ;D
seems like we're already 'there' in Leicestershire. thanks Jerry, interesting.