If you know it's guna freeze for sure try to find some large clear plastic garbage bags to put over the top of your large colas ......that will help out a lot if you can tent off most of the plant ......just get the bags off before it gets warm again .....don't know about warm water when watering but the straw will help ....GLWhat do you recommend to cover 8ft plants? Im going to water with warm water at 8pm the night in question then cover the soil with straw. So the roots should not freeze. Btw these plants are 100% indica. So they can handle cold. They have already wwnt threw a 30 degree night with no wilting or druping that seemed fine!
You can knit your sweater to whatever size you need silly.That's a lil sweater hope it don't fit your plants !!