I would start the CO2 now if not soon.
Keep in mine that maximum CO2 absorption is gained around 80 degrees Fahrenheit.
I started mine just about when my plants got to where yours are now and they have been exploding, check my journal.
What DIY method are you using?
I am just using the sugar water and yeast combo right now, but I am going to use the jello method as soon as my gallon is depleted.