Just do as I say and you will be happy.

#1....your HPS lights are inferior to CFL for taking clones that small and doing anything with them. I would...

A) Swap out the HID and go with massive CFL or REG COOL Floros. Your trouble and expense will pay off with your first harvest. IF you do not want to do this, then....

1. Raise the lights. They are stunting the plants. Raise at least a foot. This will encourage stretching which will pay off later.

2. Adjust water pH to 6.7 - 6.8 exactly.

3. Spray mist the clones as many times a day as you can. DO NOT NEGLECT THIS.

4. Add 5 drops of SuperThrive p/gallon to your water AFTER adjusting pH.

5. Have fans blowing the plants...in addition to the space between the canopy and lights. The plants must bend in the wind to stimulate stem girth which will broaden access for nutrient delivery.

6. Purchase Schultz Rooting Hormone powder at your Home Depot. Add the powder, about a pennies size worth, to your water per gallon and use EVERY OTHER WATERING. AGAIN, AFTER pH adjustments.

7. DO NOT LET YOUR SOIL DRY. Clones need more moisture to get cranking, than a plant does. NEVER LET IT BECOME DRY for at least 2 more weeks. This may mean water every other day.

If you do these things, you will see, in two weeks, rapid growth begin to set in place. Those young tender clones you have need a more blue light to do what they should be doing.

You can compensate by altering the items I listed.

Good Luck.