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This post will mostly consist of pictures, since I believe those will be the most telling. I'm trying to grow hot peppers and cucumbers from seed, and I have no problem getting them germinated. Humidity dome, heating mat, then as soon as they sprout, I remove the mat and the dome. However, the seedlings then, grow incredibly slowly, have various colors of spots on their leaves, and just look sickly overall. My general parameters are as follows:
Enclosure: 4'x4' grow tent
Light: 800 W LED hanging fixture, on 16 hours a day. Just moved it closer to the seedlings today after seeing that many of my seedlings exhibit symptoms of light deficiency.
Temperature: Between 65 and 75 degrees F
Soil: Either 5:1:1 Pine bark:Perlite:Peat or 1:1:1 Pine bark:Turface:Crushed Granite, the former with garden lime added and brought to a pH of nearly 6.5, and the latter with gypsum added.
Water: Hadn't watered for a while until yesterday (that's why everything looks soaked), and then watered with tap water with pH adjusted to 6.5
Air: I regularly open the doors to the grow tent to bring in fresh air
Fertilizer: Applied it weakly some weeks ago, thought the seedlings showed signs of nutrient burn, so I stopped
Until yesterday, I had been trying to avoid the newbie mistake of overwatering, by essentially not watering at all. I decided yesterday that the soil was far too dry, and used to soaking method to water everything pictured. I realize that doesn't help diagnose the situation as some of the plants were probably suffering from underwatering. Additionally, all of the seedlings were started in peat pots, which I know people have mixed feelings about. After reading about the mixed experiences people have with them, I decided to refrain from using them in the future. For the 5:1:1, I did not use composted bark, but I know that many others on this forum do the same and don't have issues. I would really appreciate any input anyone can give. Thanks!
The leaf curling is a sign of being too dry for a time. Your containers need to have drainage holes at or near the bottom, and to be raised perhaps in order for the drainage to occur. Then you can water more often, depending on how well the soil holds the water. If there is is a lot of organic matter (dirt or peat) it will need to be watered less, if more granite/clay-chunks/perlite it will need to be watered more. How to know? Lift a container and if it is heavy don't water, if it is light, then water it.
The first leafy structures that appear are cotyledons. They provide the food to the first couple of leaves that follow, so they will eventually turn yellow and die. That is okay. As far as lighting, each light source has different wavelengths. Check that yours include wavelengths important for plant growth. Usually the ones with 'daylight' in the name are good. Otherwise the spectrum tends toward blue, a lot of which is not important to photosynthesis.
Last edited by luv4horses; 01-18-2016 at 07:44 AM..
Very intense phosphorus deficiency and possible potassium deficiency as well. I also see that the cucumbers were the last to show symptoms - this is because their large seed contains a greater reserve of phosphorus than the small seeds of peppers. You need to start over and apply a very dilute (20% strength) all-purpose soluble fertilizer to the mix before seeding. Mix it well, and then seed. Make sure the fertilizer also has micro-nutrients added.
I actually see symptoms of light excess, not deficiency. However, this may be exacerbated by the nutrient deficiency limiting the plants' ability to cope. Move your light back to where it was. When the cotyledons show spots and cratering (like the surface of the Moon), that's a sign of excess light. Boron deficiency can worsen the symptoms of excess light, so an all-purpose fertilizer will fix this problem too.
Very intense phosphorus deficiency and possible potassium deficiency as well. I also see that the cucumbers were the last to show symptoms - this is because their large seed contains a greater reserve of phosphorus than the small seeds of peppers. You need to start over and apply a very dilute (20% strength) all-purpose soluble fertilizer to the mix before seeding. Mix it well, and then seed. Make sure the fertilizer also has micro-nutrients added.
I actually see symptoms of light excess, not deficiency. However, this may be exacerbated by the nutrient deficiency limiting the plants' ability to cope. Move your light back to where it was. When the cotyledons show spots and cratering (like the surface of the Moon), that's a sign of excess light. Boron deficiency can worsen the symptoms of excess light, so an all-purpose fertilizer will fix this problem too.
But aren't many of the seedlings pictured leggy and leaning towards the light? Wouldn't this point to light deficiency?
ABlue,
Your seedlings look like they need water, and you watered them. To be honest,
they look pretty good, remember, not all seedlings are going to make it.
Your mix should drain very well, so that's not the problem.
Just keep an eye out for watering them, mabey buy a moisture meter at any Home
Store, they are cheap.
Good luck.
I don't see any evidence of light deficiency, they look fine. When they can get natural
sunlight, provide it, a little at a time.
I've change potting media, fertilized more heavily, and flushed with RO water (not in that order). Any further advice/comments would be greatly appreciated.
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