Move seedlings outside in Spring

[jorge.reto]

Hello everyone! Where I live it is now Autumn and I collected a lot of seeds and small cuttings for propagation in the past few weeks. Spring in my region is about mid March and I was planning on moving all the new seedlings outside assuming they show visual signs of growth by then.
I will keep the temperature indoors around 20C/70F but in Spring, the outside temperatures can go as low as 5C/7F wich is a huge difference! I am afraid they might die due to the temperature shock or maybe hybernate thinking winter is comming?
Ideally I would like to move them outside as soon as possible but is it better to wait for warmer temperatures before moving the new seedlings outside?

 

[penumbra]

Most seedlings will die with this large a drop in temperature.
Better to germinate seeds later in winter so they don't have to stay inside so long.
Cuttings you will have to hold inside, preferably past last frost date.
Of course plants vary widely in terms of their needs.
It would be helpful to know where you are.

 

[Wires_Guy_wires]

Seeds can be stored in the freezer until spring comes. You don't have to germinate those now.
Seedlings you dug up, can be stored outside and they will go dormant like everything else. Just like in nature.
Cuttings can be kept inside if you really want to - and if you have enough light, pest control, and so on.

In general I keep to the last date of frost for my citrus and tropical plants, and diving from 20C to 5C is not that big of a deal for most plants. Yes, they will get a temperature shock. But we get these kind of shocks every year in nature too. Last spring we had days with 25 degrees C during the day and around 10 degrees at night; same difference of 15C. If spring arrives early, we can get 22C starting in March, but still some frosts in early May. This stuff happens.
Even on my own window sill, with the heating on it's 21 degrees C. But at night, the room temperature drops to 15 and near the window sill it can be 5-10 degrees C. Even my plants from Colombia and Australia can handle this.

 

[Svenge]

I'd sow the seeds into trays and leave them outside for the winter. They'll get the cold stratification they probably need (depending on the species) and will germinate and start growing when the temperatures are right for them. Otherwise you should at least time the stratification in the fridge or freezer so that you can sow them outside in the spring. Starting them indoors you'll either need to get some good grow lights and run them all winter or they'll most likely grow really thin and weak due to etiolation (weak growth from lack of light).