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Help! Seedlings germinated, then died - see photo

Posted by tundrasnow 3a (My Page) on
Wed, Apr 16, 14 at 15:54

What do you think could have caused these tomato seedlings to germinate, then die? I want to start a lot more seedlings, but I don't want to make the same mistakes again!! I have successfully started tomato (with 100% germination) & other seeds in the past, and they did well.

I started 40 tomato seeds in 40 3/4" soil blocks 7 days ago. The seeds were not covered with soil. Some sprouted in 3-4 days.

17 germinated, they arched up from the soil, but the cotyledons did not emerge, then they died.
9 germinated, cotyledons stood up, but the cotyledons could not shed their seed casings to get light, and are now nearly dead.
7 germinated, are still alive, but growing VERY SLOWLY. Only one looks healthy.
7 did not germinate.

Soil Temp during germination: 79�F (26�C)
Soil Temp after germination: 70�F (21�C)

The seeds are various varieties, 1 to 4 years old.

During germination they were wrapped in a plastic bag with a small airhole. It was removed when they germinated.

Once germinated, they sit in a full sun, south facing window (but, I live at latitude 51�N). This is a dry climate.

Soil Blend: 60% coconut coir, 39% worm castings; 0.3% kelp meal, of 0.3% azomite, 1% zeolite, 0.05% glacier rock dust, 0.15% all purpose organic fertilizer (Soyabean meal, Kelp meal, Alfalfa meal, Sunflower Hull Ash) [Yes, I know they don't add up to exactly 100 :) As far as I understand, these organic fertilizers don't burn roots like chemical ones do, and there is a very small quantity of them.

This does not look like damping off. They did not keel over, and there is no week spot on the stems at the soil level.

I am thinking that I probably over-watered them, and they died from lack of oxygen. Would you agree? Is there anything else that may have contributed to their poor health? I would appreciate any suggestion you might have :)

Also, should I be gently removing seed casings from the cotyledons? When I try, I usually seem to end up ripping the cotyledons!

Thank you very much!


Follow-Up Postings:

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RE: Help! Seedlings germinated, then died - see photo

Another photo


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RE: Help! Seedlings germinated, then died - see photo

I forgot to mention, the soil pH, according to my litmus paper which may not be all that accurate, is between 5.5 and 6.


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RE: Help! Seedlings germinated, then died - see photo

  • Posted by digdirt 6b-7a North AR (My Page) on
    Wed, Apr 16, 14 at 18:57

Your soil blocks are clearly too wet in the photo so it is likely a result of either over-watering OR a poorly draining, over-compacted media mix.

Soil Blend: 60% coconut coir, 39% worm castings; 0.3% kelp meal, of 0.3% azomite, 1% zeolite, 0.05% glacier rock dust, 0.15% all purpose organic fertilizer (Soyabean meal, Kelp meal, Alfalfa meal, Sunflower Hull Ash) [Yes, I know they don't add up to exactly 100 :) As far as I understand, these organic fertilizers don't burn roots like chemical ones do, and there is a very small quantity of them.

WoW! Not a germination mix at all and far too nutrient rich and complex for young seedlings. Might be great for growing on after true leaves appear (whole other discussion) but not for this stage of growth. Why all those additives? None of them are needed for any reason and can easily kill seedlings.

While it is somewhat true that organic fertilizers usually don't burn established plant roots when properly applied, that sure doesn't apply to just sprouted seedlings. When you start over skip all those additions. Germinated seedlings have all they need in the seed coat until after they develop a full set of true leaves.

You also have a number of what are called "helment-heads" in the pics - germinated plants where the seed coat remains in place binding up the cotyledons. That is usually caused by planting the seeds too shallow or left uncovered. Easy to eliminate with just a light covering of moist seed starting mix..

Hope this helps some.

Dave


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RE: Help! Seedlings germinated, then died - see photo

Wow! Thanks, Dave! You've been a big help! I am going to try again taking all your advice! It's amazing that the soil blocks are still too wet today, even after they have not been watered or covered for 3 days (and I live in a dry climate). I was definitely watering way too much! I was so worried about them drying out... I gave them a little spray everyday, when I should have been not watering them at all, and letting them dry out a bit.

If anyone else has any advice, I'll be checking back soon ;)


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RE: Help! Seedlings germinated, then died - see photo

Digdirt is right on the money with is suggestions.

Though, I'm also wondering if the soil blocks make it a bit challenging to begin with. I have no experience with them but looking at your pictures, I am wondering if they tend to try out faster compared to seed starter trays. So, you end up watering more to prevent drying it out and end up watering too much.

You said, you have had success with starting seeds in the past. Have you used the blocks back than as well or is this a new method?


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