Protecting plants from unexpected cold spells is crucial for their survival. When temperatures fluctuate, especially during spring and summer, taking proactive measures can prevent damage. For most plants, it's essential to bring them indoors before nighttime temperatures drop below 45°F (7°C), while tropical plants like lemon trees should be moved when temperatures approach 50°F (10°C). Proper indoor placement is vital, considering factors like light, temperature, and humidity.