Which of the following is NOT described as necessary for growing tomatoes?
A    The temperature of the soil should be around 12℃  before tomatoes are planted.
B    You should keep tomato plants inside in case there is danger of frost.
C    It is better to support the tomato plants with stakes or a trellis.
D    Tomatoes should be planted 1.5 meters away from other plants.

答案：D