The answer to this question is a little tricky. You only need one heat pack per box. However, depending on the size of the plants, your order could end up being shipped in multiple boxes.
As a general guideline:
I can usually fit 6, four-inch pots into one box.
I can fit 2, six-inch pots or hanging baskets into one box.
ALL plants taller than 18 inches tall have to be shipped in their own box.
When in doubt contact us and we will help you figure out how many you need.