Tuesday, September 15, 2009

Day 30: Oh no!

Oh, boy, we got problems. Many of the tomatoes are starting to yellow and brown at the leaf tips. Too much water, too little, too much fertilizer, too little, too much light, too little? The ones most affected seem to be the ones near the edge of the light - the ones on the end. So maybe it is light. Spoke with a plant person at work and she suggested increasing the light, maybe tinfoil. So I put tinfoil around the edge where the plants are yellowing the most. Not sure if it will help.

As an experiment I'm also trying to water one of the yellowing ones a lot more and watering another of the yellowing ones a lot less. I still don't think it's too little water or too little. The soil isn't bone dry, it's just lightly damp, which I think should be good. I don't think fertilizer is a problem either, if it was too little, then adding a good dose as I did Sunday would have had them perk up by now, I'd think. And if it was too much, I suspect they would have gone downhill much faster after I added the fertilizer.

So light. Probably not too much, since it's not as bright as sunlight. Maybe the photoperiod is too long, I do leave the lights on 24x7. But turning the lights off didn't seem to help either. Maybe it's too little. It does seem to impact the tomatoes on the outer edges more. I'm not sure there's much I can do beyond buying another fluorescent, but I've already put quite a lump of cash into this project already, so I'd prefer not to. It could conceivably be that the light is too close to the plants and they're getting a little scorched, but I would have thought that would impact them right away. And the temperature under the lights doesn't seem too high, although right up next to the lights there is a little heat. I suppose the next thing to do is raise the lights a little, it would cool things down a bit. but if they are getting too little light, moving the lights further away would give them even less. And since the amount of light reaching the plants drops off as the inverse square of the distance, moving the lights a little will have a big impact. Maybe the combination of the fan and the lights is drying out the leaves. Now that they've gotten a good start with the stems, maybe I can quit using the fan. I can always bring it back if they start getting leggy.

Ok, so action points:

  • Stop using the fan. (CHECK)
  • Move the lights up a little bit. (DONE)
  • Spritz the leaves, wet leaves may make them more prone to disease, but dry is BAD. I need a proper spray bottle. (Doing)
  • Wrap some more aluminum foil around the lights to increase the light they're receiving.
  • Put out a tray of water to increase the humidity. (DONE)
And maybe:

  • Buy another shop light, OUCH!
  • Set up a humidifier. This is probably overkill. (And the Mrs. says, "NO HUMIDIFIER" after reading this)
Finally, I took some new measurements:

  1. 28.6 cm
  2. 20.3 cm
  3. 16.5 cm
  4. 15.2 cm
  5. 28.6 cm
  6. 18.4 cm
  7. 17.8 cm
  8. 31.8 cm
  9. 30.5 cm
  10. 20.3 cm
UPDATE - Raised the lights 6 inches (they were about 10" away, now about 16"). Working with the setup and actually feeling the heat under the lights I think it may have been hotter than I thought down there. There's still plenty of light, so I think I'll hold off on buying another light. I guess we'll see what tomorrow brings.


  1. Did you draw that yourself? freaking cute! (looks a little like it has a banana for a head)