Book 29, Question 86
Why does a light frost harm tomatoes but not kale?
When temperatures drop below freezing, water inside leaf cells can form ice crystals that burst the cells.
Tomatoes, basil, and squash are tender and turn black and mushy after frost. Kale, spinach, and carrots are hardy: they make extra sugars that act like antifreeze, and many taste sweeter after a chilly night. Knowing which plants are tender or hardy helps you plan planting.