By Stephen:
Who’s to know what weather to expect? It makes the instructions on seed packets almost useless: ‘plant indoors three weeks before last frost’ etc. A much better method is to measure the soil temperature. I came across this technique here.
The garden possesses a soil thermometer, which was unearthed during the last shed clear out. It is designed for composting measurements but no reason why regular soil cannot be measured. It looks like one of those tools for checking whether the meat is done, but with a very long spike (is your dinosaur haunch ready?)
The photograph shows Christine M measuring the temperature at her plot, which was 58 F for the record.
The thermometer is currently in a bucket at the back of the shed, behind the left-hand door.