New to terrariums...how to provide heat?

[lechiotperdu]

Hi all, I'm new to this website hoping to get some help on my Vanilla Planifolia variegata that I have growing in a small homemade terrarium (along with some moss for humidity and a theobroma cacao, not orchids but living happily together with the vanilla)

The temperature is pretty consistent at 74 degrees, but I'd like to recreate the conditions the Vanilla likes as much as possible, and while the humidity is always around 80-90%, I'd like to be able to reach 80-90 degrees during the daytime, and let it die back down to 70 degrees at night...does anyone have any ideas how I can heat my terrarium?

I've attached pictures of my terrarium, there is an slim opening along the vertical to allow airflow.