It depends on how the plant is doing. I can grow most any plant at full strength nutrients but there are some that just can't take that much. I know that is not an answer but it's true the plant will let you know.

It's best to bump it up slowley but just know the plant does change its nutrient requirements a bit every 7-10 days so by the 3rd week of flower you should be at full strength if you are going to be. Watch for signs of over nutrients or Ph problems.

The plant will tell you how well you are doing. If your fan leaves are pointing up in a "V" sort of shape(with lights on). I call that the flying V for Victory because that means they are very happy. If they are drooping under the lights then look for problems like Ph and either to much nutrients or not enough.