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Tomato plants should not be yellow

“Do you realize the tomato plants are turning yellow?” Fatemeh asked one day.

I probably turned a little yellow myself. I had, indeed, noticed, but in my usual manner, had been trying to ignore it. I had also developed a convoluted set of theories that explained the problem.

For example: We are downwind of a meat smoking business, which means smells of delicious smokey pork waft over at regular intervals. Tomato plants are vegetarian, right? Therefore, couldn’t it be possible that they were dying from the smell of ham?

COME ON, PEOPLE. If your kid came to you with this theory, you would call them VERY CREATIVE.

But the truth is, I feared blight. I feared air pollution. I feared lack of enough sunlight. Regardless, I know this: The only thing that should be yellow on a tomato plant are the blossoms that lead to actual tomatoes.

And it wasn’t just the tomato plants suffering. The bean plants looked like they were gagging on their own selves. The basil had grown to a certain level and stopped. And even the sage was looking, um, yellow instead of green.

It was time to start doing a little research into the problem.

11 Comments on “Tomato plants should not be yellow”

  1. #1 Wife and Mommy
    on Jul 29th, 2010 at 7:09 am

    I look forward to reading the result of your research since I’m too lazy to do my own…yet my tomatoes undergo yellowing pretty much every year!

  2. #2 Heather's Garden
    on Jul 29th, 2010 at 7:31 am

    Half of mine are yellow this year too. I’m happy if I get a few tomatoes from them before they go. I’m interested to see what your research finds because I’ve always found multiple possibilities, none of which I’ve ever tried to remedy!

  3. #3 Marc
    on Jul 29th, 2010 at 7:58 am

    My guess would be that the plants are short on nutrients, especially nitrogen. Young tomatoes need a lot of nutrients, but as they age you’re suppose to cut back so that the fruit is more flavorful. When exactly that cut back is supposed to occur is somewhat of a mystery — it’s sometime after the fruit appears, but how long?

  4. #4 inadvertentgardener
    on Jul 29th, 2010 at 10:06 am

    Michelle, interesting…hopefully what I learn will be helpful!

    Heather, I still don’t have any fruit setting, which is driving me crazy. This may be an utter failure of a year. Grr.

    Marc, I had no idea about the cut back — I will have to research that, too! Nitrogen deficiency could definitely be part of the problem…

  5. #5 Outdoor Hydroponics
    on Jul 29th, 2010 at 11:57 am

    Your post made me think a little bit. I have two gardens, a dirt garden and a hydroponic garden.

    I have experienced these “yellowing” leaves in ONLY my dirt garden. My hydroponic garden seems to get problems with the leaves here and there, but not completely yellow.

    So add that little bit of info to your research :) It might give you some more insight on the problem.

    From my view, I would guess that it has to do with the roots and/or nutrients – but it could be a WIDE range of things.

    The MAIN difference with hydroponics is the nutrients and the fact that it’s soil-less. So, the nutrients are always available to the plant, unless you have some type of nutrient lockup. So that might have something to do with the soil. If the soil isnt broken down enough, so that the micros help break the organic matter into available nutrients for the plant, you might get deficiencies that are hard to correct in the soil.

    Currently Im trying to tell if I have nutrient burn or early stages of blight on a leaf in my hydroponic garden. (most likely nutrient burn from not flushing the system accordingly).

    I have all types of pics on my blog if you want to check them out and do a little comparison :)

  6. #6 Kristina
    on Jul 29th, 2010 at 12:44 pm

    If you want a quick way to get nutrients into them, you can foliar feed them with a kelp/fish emulsion blend. I do this when my plants are stressed or getting a bit yellowish and it never fails to perk them up. Let me know if you’re interested and I can type up the proportions I use. :)

  7. #7 inadvertentgardener
    on Jul 29th, 2010 at 2:08 pm

    Outdoor Hydroponics, wow! This is great info — thank you! Will check that out, and I appreciate the insights.

    Kristina, yes! Definitely interested.

  8. #8 Kristina
    on Jul 29th, 2010 at 2:15 pm

    Get a kelp/seaweed blend fertilizer. You can just mix this up in a spray bottle but we use a big garden sprayer. Use 1/8 cup per gallon of water and add in 1 tablespoon of molasses to it to make it stick to the leaves better. Spray either later at night or early in the morning.

    If this doesn’t help, let me know. I’ve got so much more to learn about gardening in general but one thing I do know is tomatoes. :D I’ve killed so many plants that I had to learn from all the mistakes I made. ;)

  9. #9 suz
    on Jul 29th, 2010 at 3:13 pm

    I get the same problem! I live on a pretty windy hill in the fog belt so I just figured it was something to do with windchap or not enough sunlight… but it doesn’t seem like Oakland would get enough fog for that to be your problem… I still got fruit last year so I didn’t worry about it but would love to know what the problem is so I can make my plants comfy (while I plan to eat their offspring!)

  10. #10 inadvertentgardener
    on Jul 30th, 2010 at 11:07 am

    Kristina, AWESOME. Thank you!

    Suz, stay tuned… :-)

  11. #11 Water: It’s a good thing – The Inadvertent Gardener
    on Jul 31st, 2010 at 10:57 am

    [...] tomato blossom did not, indeed, yield a tomato. Instead, it fell victim to whatever was causing the yellowing of the plant. It browned. It shriveled. It most certainly did not transition to a [...]

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