Three week old seedlings: Need help

[wulfgar677]

Hello everyone i'm a new grower and seem to have miserably failed my first test. I am planning to start again with new plants and would like to figure out what went wrong. Please be gentle with your feedback, I'm feeling traumatised...

I have two seedlings that shot up in the first week after germinating. Truly remarkable. Then I transplanted them in a plastic cup (full of holes, good drainage) and moved them to my tent (100cmx50cm)during the second week, now they're entering the fourth week. A week ago they were looking small, but healthy and joyful. Now they seem almost dead.

Both plants are autos. The first one is a purple queen, the second one a Taison Auto.

The bigger one, purple queen, I accidentally overwatered a week ago but she recovered...then stopped growing. I tried moving the light closer. At first she grew a bit, but then her biggest leaves started turning yellow.

The Taison Auto just...never grew. This morning I checked on her and she had shrivelled up. I thought she needed water but she's still looking awful after a day.

• They're growing in generic potting soil. Plastic cup.
• PH is between 6.5 and 7.
• Air temperature is 18° C, soil 21° C with a heat mat and a 100W InfraRed bulb.
• They get light 18/6 with a 300W led and a 5m 5050 LED strip set on bluish light. First it was 60 cms away from the top. Now it's 30cm.
• During the last two weeks I fed them around 2.5 ml each of Bionova Excel.
• Soil gets dry about every 2-3 days and then I water.

Purple Queen

Taison Auto

 

[Pepperhead]

I would suggest not using potting soil it holds too much water and is too dense and root find it hard to develop
Get some "potting mix" such as Sunshine #4 or pro mix
I
These are made mostly of peat moss and perlite and some nutrients
Have a look next time you go to a green house almost all young plants are in potting mix of some sort
Good luck on your next round

 

[skirk]

Between the heat mat and too strong/close light, they're cooked.

 

[wulfgar677]

Between the heat mat and too strong/close light, they're cooked.

even if it's just 21°C?

 

[MochaBud]

Welcome @wulfgar677

Those babies are way too wet, let them dry out till the cup feels empty...your roots are what they call "damping off" basically root rot, they need to dry out to grow in search of water...
And you can't "Water" babies, you need to spray them with just enough water to make the surface wet until they have a few sets of leaves...
And no feeding them until those sets of leaves develop, those little round leaves (cotyledons) are an embryonic feed sac for them

 

[Nunyabiz]

 

[013]

Infared bulb - that’s a heat lamp.... no bueno.

they mentioned it on watering habits but let’s try it a different way - tilt the cup to 45 degree angle and prop it up, leave it propped at an angle for an hour, I bet the soil that you thought was dry will pee out any where from a few drops to small puddle of water. Tiny plants can‘t use that much water so the roots are drowning or suffocating for lack of air.

Nothing and I do mean nothing can happen above ground unless the roots first grow underground to support a bigger plant. Seedlings are bizarre it’s like trying to fly an airplane while you build the damn thing.

no worries, we have all killed some shit to get here, also autos can be hard to learn on, might I recommend that next time you order beans then split the difference get a pack of fem autos and a pack of fem photoperiods that way you have options. Autos can be permanently stunted in a heartbeat, photos can take abuse and bounce right back