Purple Stems on Tomato Seedlings - Advice Needed!

NevadaMama(7)April 6, 2013

Hello! This is my first time starting seeds and I thought I was doing ok - please someone tell me I'm not doomed! I started my tomato seeds in trays under two grow lights (fluorescent under-cabinet-type lights) on March 17. They took approximately 5 days to germinate. I noticed the stems looking purple on March 30th and knew I needed to move them up to bigger pots immediately but my babies were sick so I'm lucky I even remembered to water them. I just moved them into 10-oz styrofoam cups yesterday in a mix of 50% seed starter and 50% organic compost (commercial, not home).

Here is my setup and some close-ups - they are 19 days old today (peppers are on the right, they are fine with no purple at all):

I am going to go to the garden center and get some fish emulsion as soon as my babies wake from their naps today. Do these look salvageable? I really hope they are ok, I don't want to have to start over! I am in Northern NV (near Tahoe) and have about 5 weeks to go before I can move them outside. Any advice or constructive criticism is welcomed, thanks so much! :)

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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

This is perfectly normal and quite common. It poses no threat to your plants.

The so-called "purple stems and leaves" issue is simply a result of their young age and inability to uptake nutrients well at this stage. That, especially if combined with cool temps, causes the appearance and as the plants mature it disappears IF they are provided with proper nutrients.

Whether your compost will provide them or not is highly questionable given that container mixes lack the active soil bacteria required to make compost nutrients available to the plants.

However your plants are also very leggy and need to be transplanted much deeper - bury most all that stem right up to just below the leaves.

How long before these can be planted into the ground outside?


    Bookmark   April 6, 2013 at 6:40PM
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Thanks so much for your reply Dave! The earliest I can transplant them to the ground outside is around May 15...it is still freezing here at night and very windy. Should I put them in bigger containers now? I've been saving quart yogurt containers all winter. Also should I start with fish emulsion now? Thanks again for your help!

Edit: Forgot to mention, the compost used is Gardner & Bloome Soil Amending Compost :)

This post was edited by NevadaMama on Sat, Apr 6, 13 at 19:16

    Bookmark   April 6, 2013 at 7:10PM
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I have read that purple stems is bad, however, I have purple stems every year and every year I have a great tomato crop. I wouldn't worry too much about that. They have their second set of leaves, so I would do as Dave suggests and bury the stems more. I would also thin them out. It will be much harder to separate them later. I would think you could even move them apart in what they are in now, one to each side until they get a little bigger and then then transplant to larger containers a week before they can go outside during the day if you have to. If you think about it, the plants in six packs are much bigger with less room than you have now. I just transplanted mine and buried the stems because they were also getting leggy. They don't seem any worse for wear.

    Bookmark   April 6, 2013 at 7:36PM
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Hi ponyexpress, and thanks for your advice :) I had thought about thinning them now too, I only planted 2 seeds per cell and was actually really surprised at how many seedlings popped up. What would be the best way to thin them? I read about snipping them at the soil line, is that a good method for tomatoes?

    Bookmark   April 6, 2013 at 7:55PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

I was surprised you didn't separate them when you transplanted them. They need to be separated and it is very easy to to. Then transplant them separately. No need to snip or thin unless you don't want the plants for some reason.

And there is no need to plant them so high in the cup either. There is no reason for them to stick out above the top of the cup. Fill the 10oz. cup 1/3 full with wet soil, poke a hole in the center with your finger and stick in the plant and its root ball, then add more wet soil to bury the stem.

If you can't plant out until mid-May then these will probably need to be transplanted a couple of times before then. Make it cooler in the area they are growing and go easy on feeding them to slow down growth.

Seedlings, under normal conditions don't require feeding, it is just optional and the need for it all depends on the growing mix you are using. You can use what you wish but fish oil is mostly N so you will need to use a very small amount and only if well diluted to 1/4 or 1/2 strength and only once every 7-10 days max. The goal is root development, not top growth.

You apparently want to grow organically, correct? If so that's fine but you need to understand how organic fertilizers and composts work, how they differ from synthetics, and why many of them aren't really useful in containers of any kind given the lack of active soil bacteria, the soil micro-herd that converts them to usable nutrients. You can compensate for the problem by using one of the quality organic growing mixes that include that bacteria.

G&B makes a good Planting/Growing Mix that would work well but their Soil Amending Compost is intended to be mixed with soil (dirt) to work.


    Bookmark   April 6, 2013 at 9:08PM
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Ok, that all makes sense, thanks! I will redo them tonight and bury the stem down further in the cup. This is my first time doing seedlings indoors and the books I read didn't really elaborate too much on the seed-starting process....I will have to pick up a book on this for future reference.

I forgot to mention that the compost I used is the G&B mix that we already mixed with our outside topsoil.....we did the raised beds in the fall, sheet mulching with grass clippings and leaves, then compost/top soil mix on top then covered with plastic to break down over the winter. I went outside and scooped up a bunch to mix in with the seed starter when I transplanted to give the seedlings a little "taste" I guess of the soil from the raised beds. We have really rocky soil here in NV and the garden center folks recommended the G&B soil amendment. Hopefully we did everything right!!

Thanks so much for your help! I will definitely take your advice and fix our seedlings up a little better :)


    Bookmark   April 6, 2013 at 9:40PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

If you are looking for info on how to grow from seed then check out all the FAQs here. They cover all the basics. Just click on the blue FAQ button right by the forum instructions near the top on the forum front page.


    Bookmark   April 6, 2013 at 11:01PM
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