Just how cold is too cold?

This is one of those novice questions up there with what exactly is direct / indirect sunlight.

Ignoring frost, when people say a plant an tolerate certain temperatures, does that mean in the day or at night time too?

For instance, I have some Ricinus communis seedlings which I've put out in a cold frame. Apparently they should be at 10C to grow well but can tolerate some colder temps, just not frost. In the day time here it's 15 - 18C already, sometimes more. But this week at night it'll go to 3-5C. Should I bring the seedlings back in, or will a few hours at night at that temp be ok?


Sent from my iPhone using Tapatalk

 

Hi Jack, I would say they'd be alright as long as they're growing strongly with true leaves on them.

 

Thanks Anthony, yes they have three true leaves on them now. It's only the Ricinus and Fuchsia triphylla I'm a bit nervous about as they're both tender.


Sent from my iPhone using Tapatalk

 

It tends to differ from plant to plant which temperatures they can handle Jack but anything below 5C I'd be thinking I was pushing my luck. If they were my seedlings I'd bring them in, better safe than sorry.

 

Is the Fuchsia a true Triphylla species or a cultivar. If the species it needs to be around 10 deg if a cultivar ( eg thalia, adinda, Mary etc I would recommend between 5 and 10 deg.

 

Ooh, ok. I've come this far with them I guess I don't want to risk it. I just brought them in. Quite comedy as it felt like I was carrying a micro rainforest on a tray! The Ricinus have grown enormous in the last few days of out door air.

They are triphylla 'Mary'. I brought them in anyway.


Sent from my iPhone using Tapatalk

 

I think it's best to be safe. If I were you if I could, now they've had a feel for fresh air I would try and keep them outside as much as I can during the day/early evening.