Something like 6500k bulbs are needed for vegging. BobBong used 6500k for his entire grow and got some pretty good buds. 2700k helps for flowering. Some use the 2700k and the 6500k together for flowering. Some use only 2700k for flowering to stretch the buds. Experiment and see what works for you.

From The Cannabis Bible by Greg Green:

CTT in Kelvin (K)/ Light Color/ Effect/

5000 to 8000/ Deep blue/ Encourages excellent leaf
and stem growth.

4000 to 5000 / Light blue/ Encourages good leaf and
stem growth.

4000/ Neutral white/ Promotes normal growth.

3700 to 4000/ Warm neutral/ Promotes rapid growth.

3000 to 37000/ Warmer yellow neutral/ Highly active
photosynthesis for all stages of growth.

1500 to 3000/ Hot orange or red/ Promotes flowering.
Horsefeathers Reviewed by Horsefeathers on . 2700K GE Soft White CFLs for Flower? The 2700K sounds right but I've read posts that said not to use soft whites. I hope it's OK to use them because that's all I can get locally and they happen to be on sale. I can get six 100 watt equivalents for under $16. Rating: 5