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

Tomato seedling stems turning red, wrong lights?

Posted by nnymom Zone 4 (My Page) on
Sat, Apr 19, 08 at 22:50

My tomato seedlings stems and veins are turning red. I am using 2 48" plant and aquarium bulbs. I am new to growing under lights and was not sure which bulbs to get. This happened to me last year as well but I didn't start using the lights until they were about 3" tall. Eventually the leaves started to get reddish and started to curl. They didn't die but were rather sickly looking. Did alright once in the ground but didn't really flourish. I grew tomatoes in my window the year before no problem. They have just gotten their first true leaves so I have not fed them yet. They are growing in peat pots with seed starting soil. I am about ready to just put them back in the window!! Any help would be appreciated.

Follow-Up Postings:

RE: Tomato seedling stems turning red, wrong lights?

1. don't use peat pots, generally, they are a pita and they dry out too easily and they don't decay fast enough when you set out the seedlings.

2. Adjust your temperature. Tomato seedlings are not at all happy in temps less than 60 degrees and do best at about 75 to 80 degrees. When the temperature is 60 or less on a regular basis, the plants cannot absorb potassium properly and develop purple stems and leaf undersides.

3. You may have a micronutrient deficiency. A photo would make it easier to tell. Just on general principles, please get a micronutrient supplement and give your seedlings an appropriate application.


RE: Tomato seedling stems turning red, wrong lights?

I like high output 5000K fluoro tubes, compared to the plant and aquarium. P&A is just a money making gimmick, plants need just photons, the more the better. The plant has all kinds of phytochromes that gather up the photons of all wavelengths to convert them into sugars and starch. I am not sure if that is what is ur problem, but I did notice in my own garden of roses, that the 5000K works much better than the 3000K, due to the requirement of blue light for synthesis of chlorophyll.

 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