Thursday 25 February 2010

Back to School - Germination Temperatures II

Last time I tried to analyse the connection between temperature and germination I got in a bit of a bind.

The following two links are the best way of summarising the facts.

First the Edinburgh climate:

Note that the soil temperature is roughly midway between the daily maximum and daily minimum and fluctuates less. For outside sowing soil temperature is probably the best guide. With some crops (onions, leeks, brassicas) to give youself a head start it is advisable to start seeds off indoors and acclimatise them to the outdoor temperature after germination in a greenhouse before planting them out once the outdoor temperature has risen.

Secondly someone has kindly summarised the data on the first chart into a digestible form.

All that is now required is to sort the data in order of ascendance of the minimum temperature in the optimum range.

Also I need to set up my 'greenhouse' and install the max/min thermometer I already have, and mabe buy a soil thermometer. Meantime, it continues to be unseasonably cold in Edinburgh. Researching this topic has kept me out of mischief.

As a footnote I have noticed that ALL the germination/temperature information on the internet appears to derive from the one American study (the one with the raw data given in the first picture of my previous post). There were a couple of glaring holes in that study where data is missing. Has no one tried to replicate this study?

I've discovered that the Council has decided to cane Edinburgh allotment holders by bumping up the rent by another £40 over the next 4 years (after doubling from £30 to £60 it in the last 5 years) My next post will try to address this local problem. Councils tend to follow each other. Is anyone else experiencing such a vicious and sustained hike in rents?

Nearly forgot the tune of the week: Money ~ Flying Lizards
Money spent: £24 (Impulse buy of 6 fencing posts)
Time spent: 1hr - fencing duties.


  1. well it sounds like you've been busy collaborating all this data...and I guess I could do something along those lines...but checking the soil temperature really doesn't appeal too much. Think I will just go with what I usually do and plant when I feel the temps. increase...after all we still managed to grow crops in the dark ages!!!!

  2. I start most of my seeds off indoors and then move them outdoors when the weather improves, I usually go with time of year rather than temperature when planting. As for the cost of the allotment, I pay £20 per year, but my plot is a little over half a plot.

  3. Hi Mal - thought I would update you with your question of the rhubarb you left on my blog. well, they don't bring any soil in, they clean the crowns off, but the depth of the crown is basically about 50cm, and then they just mist them for watering. Was very strange!!! But very interesting! Cat @ manor Stables

  4. Great, Cat. Sounds like a fascinating visit. Thanks for sharing it and answering all my questions. Mal