Please Help Identify this....

alamo5000 · December 31, 2010

I have a greenhouse and some of my plants have this kind of purplish sort of tint to them. The plants seem to be growing just fine...so far...

But I can't be too careful.

Last year in my outside garden something sort of like this hit the plants... it didn't kill any of them, although it killed off a few branches...but ultimately the plants survived...

Anyone have any ideas about those purple color stalks?

dice · January 2, 2011

It does not ring any bells. Look on the bottoms of the
lower leaves. Do they look purple? That would be a phosphate
deficiency, possibly from cold temperatures rather than
an actual lack of phosphate in the soil or container media.
(Sometimes it will show on the stems, too.)

Otherwise, ?

Worth1 · January 2, 2011

Alamo it is what dice said I think, 'our temps at night have been cold.

alamo5000 · January 2, 2011

Its possible that is just 'cold'. The other night it was 24 degrees. But in the greenhouse it was maybe 40-45ish.

Cold can do this? weird. I learn something new every day.

None the less as a precaution I sprayed my plants with fungicide. In that greenhouse it was probably a good preventative measure anyway.

Worth1 · January 2, 2011

Quote:

Originally Posted by alamo5000

Its possible that is just 'cold'. The other night it was 24 degrees. But in the greenhouse it was maybe 40-45ish.

Cold can do this? weird. I learn something new every day.

None the less as a precaution I sprayed my plants with fungicide. In that greenhouse it was probably a good preventative measure anyway.

Yes cold will do this. When the temps warm up to 60 and 70 at night the purple will go away.

Like dice said at cooler temps they cant take up phosphorus.
Eggplant is worse than tomatoes for it.
I have put out many purple plants and like I said as soon as it warmed up they shot up like rockets.

Worth

**carolyn137** · January 3, 2011

Alamo had asked me about this and I suggested asking folks who grew plants in greenhouses, but alamo, at the time you told me it was just one plant and the pictures I saw were a bit different and what's now being called purple looked black to me. So I was more concerned with a possible infectious disease rather than an environmental condition.

If more than one plant is involved and the blotches on the stems are purple, then yes, it could well be lack of P. Do the undersides of the leaves also have a purple cast to them? If so you can prove lack of P to yourself by spraying the the plants with dilute liquid fish or seaweed emulsion b'c then the P will be taken up by the foliage and bypass the root uptake which with cold conditions does not allow for P uptake via the roots.

Even with my outside plants a cold spell early in the season will turn the undersides of the leaves and usually the stems purple but I don't spray anything b/c I know that as soon as the weather warms up the normal green of the plant will return.

dice · January 3, 2011

Here is a general reference on mineral deficiencies, with
pictures of tomato leaves for examples:
http://4e.plantphys.net/article.php?ch=5&id=289

The symptoms of phosphorus deficiency shown in that
document are quite a bit more severe than simple purpling
from cold temperatures. The pictures in the first post in this
thread in another forum are closer to the mark:
http://www.helpfulgardener.com/phpBB...ic.php?t=15657

(High pH can interfere with phosphorus uptake, too, which
may have been that person's most significant problem. See
this document for a general overview on the relationship
between pH levels in soil or container media and phosphorus
uptake:
http://www.selectedplants.com/OrthoPhosphate.htm
)

December 31, 2010	#1
alamo5000 Tomatovillian™ Join Date: Nov 2010 Location: near Houston Texas, zone 8b/9a Posts: 114	Please Help Identify this.... I have a greenhouse and some of my plants have this kind of purplish sort of tint to them. The plants seem to be growing just fine...so far... But I can't be too careful. Last year in my outside garden something sort of like this hit the plants... it didn't kill any of them, although it killed off a few branches...but ultimately the plants survived... Anyone have any ideas about those purple color stalks?

January 2, 2011	#2
dice Tomatovillian™ Join Date: Jan 2007 Location: PNW Posts: 4,743	It does not ring any bells. Look on the bottoms of the lower leaves. Do they look purple? That would be a phosphate deficiency, possibly from cold temperatures rather than an actual lack of phosphate in the soil or container media. (Sometimes it will show on the stems, too.) Otherwise, ? __________________ -- alias

January 3, 2011	#6
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	Alamo had asked me about this and I suggested asking folks who grew plants in greenhouses, but alamo, at the time you told me it was just one plant and the pictures I saw were a bit different and what's now being called purple looked black to me. So I was more concerned with a possible infectious disease rather than an environmental condition. If more than one plant is involved and the blotches on the stems are purple, then yes, it could well be lack of P. Do the undersides of the leaves also have a purple cast to them? If so you can prove lack of P to yourself by spraying the the plants with dilute liquid fish or seaweed emulsion b'c then the P will be taken up by the foliage and bypass the root uptake which with cold conditions does not allow for P uptake via the roots. Even with my outside plants a cold spell early in the season will turn the undersides of the leaves and usually the stems purple but I don't spray anything b/c I know that as soon as the weather warms up the normal green of the plant will return. __________________ Carolyn

January 3, 2011	#7
dice Tomatovillian™ Join Date: Jan 2007 Location: PNW Posts: 4,743	Here is a general reference on mineral deficiencies, with pictures of tomato leaves for examples: http://4e.plantphys.net/article.php?ch=5&id=289 The symptoms of phosphorus deficiency shown in that document are quite a bit more severe than simple purpling from cold temperatures. The pictures in the first post in this thread in another forum are closer to the mark: http://www.helpfulgardener.com/phpBB...ic.php?t=15657 (High pH can interfere with phosphorus uptake, too, which may have been that person's most significant problem. See this document for a general overview on the relationship between pH levels in soil or container media and phosphorus uptake: http://www.selectedplants.com/OrthoPhosphate.htm ) __________________ -- alias

January 2, 2011	#3
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Alamo it is what dice said I think, 'our temps at night have been cold.