blue spectrum. It's not always clearly labelled either which is kind of annoying. But they will call the yellow ones "standard" or 2700K and the blue ones "daylight" or 6500K. The numbers are the degrees in Kelvin at which they burn which is what determines the wavelength and color of light they produce.like are the bulbs blue or just like blue spectum ?
nice lookin plants im excited to see those ladies grow up