Purple underneath seedling leaves, then they curl up and die

[z_willus_d]

Hello,

I apologize for the abruptness of this post, but I'd just finished typing up a good one and my computer ate it. It ate a good deal of my patience at the same time.

My situation is as follows. I have 40 seedlings that are of various ages, mainly around 2 weeks old since transplanting up to 6" pots. The vast majority of the seedlings are exhibiting an deep purple color on the underside of their leaves. I've had this in the past and it's never been an issue (not major in any case). I've read it might have something to do with phosphate uptake issues, which can have to do with (a) no phosphate or (b) cold soil temps or (c)...? In any case, I've got very warm temps in my grow room (68F-85F) and I'm using what I've read is fairly rich FoxFarms Ocean Forest /Floor potting mix (1 part Light Warrior, 3/4 part Ocean Floor).

I wouldn't write this thread if it were only a problem of purple (underside) leaves, but it's more than that. Yesterday I noticed wilting on the first set of true leaves on one of my seedlings, and within 1-2 hours those leaves (/w branch) had curled up and atrophied from the main stem. Since then, five more plants have followed suit. The rest of the plant seems healthy, but this scares me.

I've attached pics showing this condition on a couple of the seedlings. I'm afraid the problem will move on up to the next set of leaves and so on. Any ideas what this could be? Should I do something? If so, what?

Note, until this morning I hadn't added any fertilizer or additives, other than an application of Actinovate/MycoGrow/BiotaMax (all mycos) and Roots Excelurator. Those are all quite benign. This morning, I watered with a very dilute fish/kelp extract, hoping to perhaps add some N and P to the mix. I leave an oscillating fan directed at the seedlings for 1/2 the light day, which is currently set at ~16-18 hours a day (dark the rest).

Any questions I can answer to help diagnosis this syndrome, please let me know.

Thanks all!
-naysen

[Dutch]

Naysen,
Have you tried "Exel LG" or "Agri Fos".
Dutch

[rnewste]

Naysen,

You can see in a couple of the photos where the branches / leaves are sharply pointing upwards. That, coupled with the wilted leaves is indicative of stress, frequently caused by fertilization. There is plenty of necessary fertilizer embedded within the Ocean Forest, which according to Fox Farm will last 2 months without the need for additional fertilizer.

Seedlings do not need additional additives at this point in their life cycle. I think you are hitting them with too much "stuff" in their infancy.

Raybo

[z_willus_d]

Originally Posted by Dutch

Naysen,
Have you tried "Exel LG" or "Agri Fos".
Dutch

Dutch, no I have not yet, mainly because I haven't been able to find a place to purchase other than online with a nice $10+ dollar shipping hike. What makes you think this issue is one of systemic fungal attack or the like?

Thanks for posting,
Naysen

[Fusion_power]

Check your watering. At this stage, seedlings should be let dry out enough that they just start to wilt. This encourages the roots to grow and keeps phytothora (damping off) from killing the plant.

DarJones

[z_willus_d]

Originally Posted by rnewste

Naysen,

You can see in a couple of the photos where the branches / leaves are sharply pointing upwards. That, coupled with the wilted leaves is indicative of stress, frequently caused by fertilization. There is plenty of necessary fertilizer embedded within the Ocean Forest, which according to Fox Farm will last 2 months without the need for additional fertilizer.

Seedlings do not need additional additives at this point in their life cycle. I think you are hitting them with too much "stuff" in their infancy.

Raybo

Ray, but remember, I'm using 3 parts Ocean Forest to 4 parts Light warrior, so less than half. Moreover, all this started setting on before I hit the plants with anything. Now, as of this morning, I did water with a dilute mix of liquid kelp and fish, but everything I've read suggests that's a standard "play" at this age in the seedling's life-cycle.

When I got home tonight, I found another four seedlings in similar straights. I also found a couple that looked on the precipice, and the leaves that started wilting were a deep, deep purple. It seems the unaffected leaves are less purple farther up the plant stem and on the healthier ones. I have to figure this is somehow tied to the purple color on the underside of the leaves. Other than phosphorus deficiency, are there any other conditions that purple on the underside of seedling leaves signals?

Thanks,
Naysen

[z_willus_d]

Ok DarJones, you're right about that. I've learned the hardway what happens with over-watering. I've been watering about every three days and only 1.5 squirts from a standard turkey baster. I have two moisture meters and both read bone dry (a quick spike to 2 on insertion then back to .5/1 stabilized) at the point of watering. A couple times now, the plants were wilting due to lack of water, but you're right, they perk right back up after a little liquid. Can over-watering result in a deep purple color on the reverse of seedling leafs? I know I seem fixated on that color issue, but it's just striking how the color intensity increases on the dying leafs.

Thanks,
Naysen

[Dutch]

Naysen I'm not so sure that it is a fungal attack, since reading Raybo comments.
I've checking some things like maybe the roots excelurator is too hot.
Please see the attached MSDS below.
Number 2 is missing Potash info
Number 12 Growth Stimulator: high concentrations may cause plant burns.

Dutch

[rnewste]

Naysen,

A suggestion when potting up your next series of plants. Add in about 25% Perlite into the Light Warrior / Ocean Forest Mix. What I observed when potting up in the Ocean Forest was that it stays too moist alone. 3 scoops Mix along with 1 scoop Perlite in the mixing bucket provides for good drainage.

Again, it is not normal for the leaves to be pointing up almost vertical. Something is not in harmony when this happens.

Raybo

[Dutch]

Originally Posted by z_willus_d

Dutch, no I have not yet, mainly because I haven't been able to find a place to purchase other than online with a nice $10+ dollar shipping hike. What makes you think this issue is one of systemic fungal attack or the like?

Thanks for posting,
Naysen

The reason a fungal attack came to mind was the fact that you had problem with "damping off' which is caused by one of a half a dozen of fungal diseases earlier in the year. It has been my experience that Exel LG or Agri Fos takes care of most the fungal diseases that cause damping off.
If you use Exel LG or Agri Fos mix it half strengh. Like 1 tablespoon per gallon.
Dutch

[z_willus_d]

Thanks Dutch, I'll keep that in mind if I ever manage to procure the fungicide. I will sooner or later when I decide to bite the bullet on the shipping cost.
-naysen

[z_willus_d]

Ray, not all the plants (even of those that have suffered) have upward pointing leaves, and many have downward curling leafs. I agree that adding a bit of Perlite to the mix couldn't hurt. I'm not so sure they plants are over damp, but I will not rule it out.

I was in the process of writing a response to Dutch's penultimate post, but my computer again crashed. My wife demands food, so that rewrite will have to wait.

Thanks all for the help.
-naysen

[z_willus_d]

Originally Posted by Dutch

Naysen I'm not so sure that it is a fungal attack, since reading Raybo comments.
I've checking some things like maybe the roots excelurator is too hot.
Please see the attached MSDS below.
Number 2 is missing Potash info
Number 12 Growth Stimulator: high concentrations may cause plant burns.

Dutch

Dutch, I want to thank you for passing along the disclosure form for the House and Garden Excelurator product. I knew it had trace amounts of NPK, but hadn't seen the rest. After potting the seedling up Feb. 25, I administered a half-strength (1/4 tsp = ~.5ml per Gal) application of the Roots Excelurator product. I haven't applied any since that time, despite the instructions, which indicate the product should be applied regularly. On 3/3/12 I applied the following Myco products (my notes):
"Mixed 1TBS Blackstrap Molasses, 1/4 tsp Actinovate, 1/4 tsp MycoGrow, 1/2 tsp Great White, and a few crumbs of BiotaMax tab with 1 gal of water. Each pot got 1.5 squirts.?"

Other than the above, the seedlings received a half-strength dose of liquid kelp/fish with their watering this morning. That's all they've received. Other than the fish/kelp (2-1-1), I don't believe any of the products I administered are a significant source for N/P/K. I'm not ruling over-fertilization out, but I'd like to understand just how it could happen based on my records of what the plants received.

The only other possibility I can think of is that many of the seedlings that have exhibited the issue are under an LED light. I grew my dwarf seedling up under the same light earlier last year, so I don't think it's completely to blame. I still like to understand the correlation of purple with the necrotic leafs.

Best and have a good evening all.
-naysen

[RayR]

Naysen, did you pull up any of the affected seedlings and look at the roots? If they are not white and healthy, there's something wrong down below. I agree with Raybo, they certainly look stressed. I'd lay off any ferts, it might be aggravating the problem, they shouldn't need anything at that size considering the mix you are using. Purpling under the leaves and necrosis would indicate a serious phosphorus uptake problem at the roots, but what is causing it is the question. If it's not cold soil then acidic conditions or wet feet are other possibilities.
I had a problem last year with some seedlings where the cotyledons wound start to turn brown at the tips and then the whole cot would turn black and die. No purple under the true leave though. Those seedlings just withered away and died Never got an answer on that one, just chalked it up to the mysterious crud disease.

[mcsee]

Naysen - Just a thought, ask your wife if she has any Cinnamon and dust some of your remaining seedlings and mix with it and see if they succumb too. Cinnamon is a natural fungicide and helps where Damping Off is a problem.