Hello there Myusernamewastaken.
The screw bulbs are weak from what I understand. You should get a 2 foot tube with a fixture. They are the strongest UV-b emitters so far. I get AgroMax Pure UV T5 tube from htgsupply.com. Make sure your fixture has an aluminum reflector as plastic absorbs UV light, so a plastic reflector wont work. I have been using GrowBright 2-Foot High-Output T5 Fluorescent Grow Light Fixture from Amazon.
This combination is the cheapest I can find and is very effective.
Good luck with your illuminations.
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