Answer: Sometimes the top of the soil will turn green with algae or some other growth. It can be sign that the soil is too moist, that you have overfertilized, that temperatures are too warm or too cold, or it can be nothing to worry about. Keep the soil evenly moist but not sopping wet, and fertilize using a very dilute solution. If you are following those steps and your plants look healthy, don't worry.
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