All my seedling died over the course of 2 days!

[SydneyGee]

Hello,

We have quite a variety of seedlings in small starter planters that we started late September. The seedlings all took nearly three weeks to sprout, and have been very spindly and weak since. We had them covered with transparent plastic until the middle of October, and since then have had them in somewhat shaded spots to shield from the sun. It has been excruciatingly slow growing, as the heat has caused many young plants to die and become wilted.
We had a one week period of cold rains then back up to the high 80's again for the last two weeks. Last week the seedlings began to turn yellow, so we figured it was lack of sun and moved them in their planters to our garden box, which gets the most sun throughout the day. They seemed to be doing better, and returned to a slightly brighter green, but all of the sudden, this morning, 3/4 of them had died! The stems at the base had melted into nothing, the leaves were dry and collapsed, only a few of the herb and tomato seeds survived!

Important information:
They have been fertilized with an organic fertilizer once in their 2.5 month life span.
They are in varying sizes of small plastic planter cups, not over crowded. Only 1 or 2 seeds to a cup.
They are in a compost/soil mix 50/50.
Water once - twice a day due to the tiny enclosure, heat, and dry winds we have had.
No predators/disease has been spotted other than turning yellow, a couple of the chard/bok choy have crisped leaves.

Seedlings:
Carrots - all died
Tomatoes - Fine
Squash - never sprouted since September (3 planted)
Pumpkin - died
Micro green - died
Lettuce - died
Bok Choy - dying
Chives - fine
Basil - fine
Swiss chard - dying

Any ideas? Bad weather? Bad luck? Late season?

 

[Chuck]

Hello,

We have quite a variety of seedlings in small starter planters that we started late September. The seedlings all took nearly three weeks to sprout, and have been very spindly and weak since. We had them covered with transparent plastic until the middle of October, and since then have had them in somewhat shaded spots to shield from the sun. It has been excruciatingly slow growing, as the heat has caused many young plants to die and become wilted.
We had a one week period of cold rains then back up to the high 80's again for the last two weeks. Last week the seedlings began to turn yellow, so we figured it was lack of sun and moved them in their planters to our garden box, which gets the most sun throughout the day. They seemed to be doing better, and returned to a slightly brighter green, but all of the sudden, this morning, 3/4 of them had died! The stems at the base had melted into nothing, the leaves were dry and collapsed, only a few of the herb and tomato seeds survived!

Important information:
They have been fertilized with an organic fertilizer once in their 2.5 month life span.
They are in varying sizes of small plastic planter cups, not over crowded. Only 1 or 2 seeds to a cup.
They are in a compost/soil mix 50/50.
Water once - twice a day due to the tiny enclosure, heat, and dry winds we have had.
No predators/disease has been spotted other than turning yellow, a couple of the chard/bok choy have crisped leaves.

Seedlings:
Carrots - all died
Tomatoes - Fine
Squash - never sprouted since September (3 planted)
Pumpkin - died
Micro green - died
Lettuce - died
Bok Choy - dying
Chives - fine
Basil - fine
Swiss chard - dying

Any ideas? Bad weather? Bad luck? Late season?

I think your main problem is a disease called damping off disease. It only affects young seedlings. The second problem is shading them. Vegetables need all the light you can give, especially this time of year when days are shorter. 3 weeks to germination is long, it should be about a week to 10 days at the longest. You are watering too much. Watering every day is too often. Saturate the soil in their container and leave it alone until it dries out.

To stop damping off disease, mix whole ground cornmeal, not the enriched kind, into your seed planting medium, sow your seeds and cover the top of the soil with more cornmeal.

 

[SydneyGee]

Thank you for your reply. After less than half a day, the soil throughout the container is bone dry. The cups are only about 2.5" tall and 2" wide with three large drainage holes.

It has been over 85 for almost two weeks in a row, with high winds. I should still water less? They seem quite wilted if not, as I said the soil is completely dry after one day.

That is perplexing, as they were fine (growing slowly but fine) in the sun-filtered shade, and the problems increased once put in the sun.

That is an interesting solution, what in the cornmeal prevents/cures the disease? What causes the disease?

 

[Chuck]

Thank you for your reply. After less than half a day, the soil throughout the container is bone dry. The cups are only about 2.5" tall and 2" wide with three large drainage holes.

It has been over 85 for almost two weeks in a row, with high winds. I should still water less? They seem quite wilted if not, as I said the soil is completely dry after one day.

That is perplexing, as they were fine (growing slowly but fine) in the sun-filtered shade, and the problems increased once put in the sun.

That is an interesting solution, what in the cornmeal prevents/cures the disease? What causes the disease?

Your containers are too small. Once the plants have true leaves they should be transplanted into a larger container. If they don't have true leaves this is a for sure sign of damping off. The cornmeal is an interesting item as it prevents the fungal disease of damping off. Whole ground cornmeal or horticultural cornmeal is the favorite growing medium for tricoderma which is a very beneficial fungus which happens to stop damping off. Damping off is a fungal disease which is inherent in most soils. Even sterilized potting mix may have it. What the cornmeal does is allow the tricoderma to grow on it and reproduce. When it reproduces it has the ability to kill harmful fungi such as damping off.

Sun filtered shade is great for some plants but not vegetables. They need and require all of the sun light they can get. You do not move plants which have been in the shade into direct sunlight. You do it gradually. Temperatures do not matter all that much and 85 is basically cool for most vegetables.

When you water, water completely. Saturate the soil. But by growing in a 2 x 2 container which is a seed starting container you are defeating your purpose when it comes to growing a plant. It will dry out very rapidly and if they survive they will become root bound and need even more water. Turning yellow is common with overwatering plants in small containers. It leaches all of the nutrients from the soil. Basically what I am saying is to repot your plants into larger containers as soon as you can.

 

[SydneyGee]

They do not have true leaves. They are still just spindly seedlings, no bigger than this

I will try the cornmeal!

I had read that anything over 80 would cause bitter and tough crops, and from our summer crop (when temperatures were a steady 100) this was in fact quite true. Our cucumbers were so sour and bitter they tasted like poison!

At this point would it just be better to plant them directly into the garden box they are just sitting on top of? There are already some micro-greens, maturing lettuce, and garlic growing quite happily in there.

 

[Chuck]

They do not have true leaves. They are still just spindly seedlings, no bigger than this

I will try the cornmeal!

I had read that anything over 80 would cause bitter and tough crops, and from our summer crop (when temperatures were a steady 100) this was in fact quite true. Our cucumbers were so sour and bitter they tasted like poison!

At this point would it just be better to plant them directly into the garden box they are just sitting on top of? There are already some micro-greens, maturing lettuce, and garlic growing quite happily in there.

Steady 100F temps will in fact affect the taste of some vegetables. However 80's or 90's will not unless they are cool weather crops. I would direct plant into a much larger container

 

[SydneyGee]

That is great advice about watering deeply, I had always been taught it is ok to water as often as the soil dries out. But it only makes sense that all the nutrients wash out too....