To mention what options you have besides CFLs.
Is 4000k good for plants. Would be a good idea. This spectrum is good for full cycle cannabis growth. 3000K4000K warm LED spectrums happen to have an ideal amount of blue light and a good amount of yellow light for growth power.
4000K is an often overlooked color temperature as it falls right in between warm white 2700K3000K and daylight white 5000K6500K color options. The reason for this is that at the warm white color temperature the ratio of wavelength is ideal for plant. Using only white diodes in a grow light goes against the whole purpose of applying LED technology to focus specific light wavelengths needed for the growth of plants.
The 4000K has a more balanced spectrum whereas 6500K is rich in. However you will need a higher wattage and more powerful LED diodes in order to produce enough PAR for your garden. Ideal and balanced for veg.
Which is brighter 4000k or 6500k. And to showcase our own selection of 6500K CFLs. The three primary types of color temperature for light bulbs are.
As one would expect is most definitely on the cool side when compared to typical warm white lighting options but is also on the warm side when compared to daylight color temperatures. I think 4000k would work just fine. Because 4000K grow lights contain a higher proportion of blue light than other grow lights they tend to be the better option for growing plants indoors.
Traditional wisdom in regards to light and plant growth is that cooler color temperatures more blue wavelengths assist with seedling growth while warmer color temperatures more red wavelengths help with the. Apparently from the things Ive read Daylight color or 5000K bulbs are the best. 4000K is a good all around.

