Return to the Growing under Lights Forum | Post a Follow-Up

T8-T12 lights

Posted by brandond 6 ( on
Sat, Mar 20, 10 at 7:57

I have some shop lights I bought off of craigslist for starting seeds. IM guessing they are T12 lights but not sure. I placed some sylvania T12 energy efficient bulbs in them and they work fine. They bulbs that were in the fixtre was an older GE 40watt bulb. The bulbs looked the same. I had read somewhere on here or elswhere about placing T12 bulbs in a T8 fixture and how it can shorten the life of the ballast. I could not find anywhere on the fixture where it said to use a certain type bulb or wattage bulb. I figured if the bulb works fine then I have the right one, Is this the right mentality of have I made a mistake. thanks so much

Follow-Up Postings:

RE: T8-T12 lights

Check the ballast for recommended wattages.

RE: T8-T12 lights

The lights are actually working fine. They take awhile to warm up and then the rippling stops. Now they are not quite as bright as the GE 40 watt bulbs but they are ok. The sylvania is 34 watt and supposedy more efficent, it just doesnt seem as bright as the 40 watt bulb. Again I dont see anywhere on the balllast where it says what type of bulb to use. I bought the fixtures used on craigslist and they already had some older 40 watt lights in them. My main question was are T8 and T12 lights completly different, as in different size bulbs.

RE: T8-T12 lights

Yes the bulbs are different in width. T8s are approx 1". T12 are approx 1 3/8".
As stated above "Check the ballast for recommended wattages". They may only be 32w. T8s usually put out more lumens per watt. The ballast is inside the fixture.
BTW you need as much light as you can get, get rid of the 34w bulbs no matter the actual wattage. Use them in the kitchen or the garage but not on plants.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Growing under Lights Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here