Reddit mentions of Leviton 61-I Non-Grounded Lamp Holder Adapter, 660 W, 125 Vac, Medium Base, Ivory

If it starts flowering while still a clone and then goes back to veg before finishing so that you can grow it bigger and then flowered again for you to harvest, it will totally stress it out, can screw up its growth cycle and possibly go hermie. Only once it gets more than 10 or 11 hours of darkness at a time will it think "fall/winter is coming soon" and start budding, so all you need to do to make sure it doesn't start flowering yet is keep a light shining on it 24 hours a day. Technically just about any light bright enough for people to see in would stop it from flowering, but to keep it growing healthy instead of stretching out and losing leaves you can make a super easy cheap CFL light and keep it nice and close.

Go to Home Depot, Lowes, Walmart, or wherever and get one cheapo extension cord, two socket to lamp adapters, and two or more "daylight" or "full spectrum" CFL bulbs that are at least 20W actual or 100W "equivalent wattage." They'll likely be cheaper in the actual store than the Amazon price due to shipping. If you get a multi-pack of bulbs, you can always use the extras around your house though. Plug the adapters in opposite plugs of the extension cord so they both fit on, screw a bulb into each socket, and hang it a few inches from your plant.

http://www.amazon.com/Leviton-61-I-Outlet-Lampholder-Adapter/dp/B000RN18GK/ref=pd_cp_hi_2

those are cheaper, same thing, different color. I have 3 of them.