Repotting aftercare late winter early spring frost

[Malix]

I am located in zone 9a. Sonoma county Ca. I have been busy repotting lately. Mostly deciduous but starting some conifers soon.

I am wondering if any protection is needed from frost in my kind of environment. We have low temps on the coldest days of 32 to 34 degrees. Day time temps of 50’s to 60’s o. Average. So it only get to freezing temps for the coldest hour or two of the night. I don’t think I need to protect my trees from those temps but have kept them in a hoop house because I have one.
Just wondering if it’s at all necessary? I’m guessing not but figured it doesn’t hurt to ask.

 

[Dav4]

As long as the soil doesn't freeze solid, you should be fine.

 

[Shibui]

Temps here are similar to your area. I start repotting mid winter and continue through to mid spring. Many trees get severe root pruning in that time. All bonsai go straight back to the bonsai benches open to the elements. A few hours of just below freezing will not hurt any temperate species you are likely to grow outdoors.
The fuss that those from cooler latitudes go to really put the wind up beginners in regions with better climates and are completely unnecessary for us. Just put your trees back on the benches where they belong after repotting.