How long until weeds grow back? We need hundreds of stems.

[Captain America]

Grass grows back fairly quickly, but the weeds are not growing back and our castle requires several hundred weed stems to build. What's the regrowth time of weeds?

[Pizza Cake]

I'm not really sure, it's like a cooldown timer that works with in game hours.
I was walking back to my base with grass planks, I noticed a weed stem that I chopped a while ago. Walked back a sec later, all the sudden it grew back.
I guess it takes 2 in game days, 38 minutes?