Kitchen Garden Forum

How much warmer than outside is my PT likely to be at night. It has a thermal cover, and it isn’t too exposed.
The night temps this week have been around 6 degrees

It’s a pain at the moment as in the day is really warm but I realise it takes a nose dive at night.
As the PT is on the plot, I can’t pop out in the early evening and cover everything with fleece
So should i just cover with fleece on the night with predicted frost, I’d have to do this at about 3pm in the afternoon.

Johnboy will be much more able to answer this than me.

As a general rule I assume that the temperature inside my polytunnel will be much the same as outside: i.e. if it's freezing outside it will, by morning, be freezing inside as well. The main benefit of tunnels is protection from wind and wet rather than cold.

Hi Alan,
There are many times when it is colder inside a tunnel than outside.
I have had plants frozen solid in their modules when the outside temperature has not reached freezing at any time during the night.
JB.

I use a min/max thermometer to keep an eye on mine. I've got an 'inner sanctum' set up in one of them, made from a wooden frame and covered in bubble wrap which I keep frost free with a heater and then, once the tomatoe seedlings go in there, I set the heater to 10 degrees.