It sounds like plant stress. It could be due to too much water and or a lack of nutrients. Try easing up on watering & giving them some tomato food.

It's a common thing with seedlings but poses no problems or threat. It is a result of too cool temps and other stressing factors and disappears quickly once they are transplanted to the garden. If you can't transplant them anytime soon can you raise the temps in their area? It comes up often for discussion and you'll find several discussions about this searching something like "purple leaves" and such.

Dave

there is no purple above the cotyledons.

16 hours/7 days have kept me from given them proper care.
I think the pots are way too small.

would that do it?

16 hours/7 days have kept me from given them proper care.
I think the pots are way too small.

would that do it?

*****

No, too small pots would usually not do that.

How big are the seedlings now and what is the temperature where they are now and what have you been giving them other than plain water?

It isn't clear to me if you're talking about very young seedlings not yet transplanted, or you've transplanted them into individual pots. And if so, what size individual pots and what are the conditions, again, as I asked above.

it isn't uncommon to find a purple area where each stem attches to the main stem and as said above, it isn't uncommon to find purple stems below the cotyledons, so I/m not real sure what the problem is that encouraged you to ask here. ( smile)

Carolyn

> How big are the seedlings now

4"-12", depending

> and what is the temperature where they are now

pretty warm. *guessing* 75 degree F

> what have you been giving them other than plain water?

water, and a low dose of miracle grow plant food 2x in a month. The live in quality a soilless potting mix.

Sometimes too much as per previous thread "Are maxiforts freaks of nature" / edema post.
Maybe too little lately to compensate for previous overwatering.
1 gallon for 20 4" pots, 2x per week, bottom fed.

> very young seedlings not yet transplanted

about one month old, + or - 2 weeks for some plants.

> or you've transplanted them into individual pots

4" pots, not yet trans planted.

> it isn't uncommon to find purple stems below the cotyledons

I'm a newb. I noticed it and thought "that's weird"

Last year I had phosphorous deficiency big time,
was worried this year I had the same or some other problem.

I didn't look at your page to see where you live but I'd get those taller ones about a foot high into a cooler place ASAP.

When do you anticipate transplanting outside? YOu still have to harden off your plants to be able to put them outside and that takes about a week to do outside, but I assume you did that last year as well.

Carolyn, who did not read your maxifort thread b/c grafting doesn't interest me that much given what increased disease tolerances can or can't do in specific geographic locations.

I'd also stop the fertilizing for now.

if the area elskunkito is talking about is the "hypocotyle" region, then the purpling is the normal genetic expression of a pigment called anthocyanin

there are several gene mutations that can cause this region not to purple and this is an example of one, al compared to the dominant or "normal" form with purpling {{gwi:1295625}}

because several gene mutations can produce the lack of purpling, if one grows out large numbers of normal seedlings they are fairly like to find a few without purpling

the purpling can even be on the undersides of the cotyledons in some cases.

If purpling occurs later in growth, that could be lack of phosphorus or a lack of phospohorus uptake due to low temperature (it could also be another mutation for purplish leaves or stems)

Carolyn Wrote:
it isn't uncommon to find purple stems below the cotyledons

John wrote:

if the area elskunkito is talking about is the "hypocotyle" region, then the purpling is the normal genetic expression of a pigment called anthocyanin

*****

Agreed John, as I wrote above and K's pictures illustrate it quite nicely.

Carolyn

Bottom line - it's normal and no problem. ;)

The reason I suggested searching "purple leaves" is that is usually in the title or content that most who post this question use. That or "purple stems on my tomatoes" or "why are my tomato seedlings purple" or " what's with the purple on my tomato seedlings", etc. In other words, it's common.

More importantly - where do you live/garden zone? None of your posts that I have read indicate that and neither does your page. You have 12" tall seedlings - how soon can they be hardened off and transplanted into the garden? If not soon, then transplant them into much deeper containers like 16 oz. cups (with drain holes) and transplant them very deeply.

Good luck. ;)

Dave

Dave

Bottom line - it's normal and no problem. ;)

thanks

@all thanks, yes its the hypocotyle I'm talking about

@carolyn, digdirt
It will suprise you to learn I am zone ?7? or maybe 8.
Seattle area. safe last frost is ?May 15? or June 1st.

But I plan on planting them out in mid march.