Help with seedlings. First grow.

JimmyJackCorn said:

I am not a coco guy, but I agree with the folks saying it's a light and air issue.

I had good luck with seedlings in soil with my TSW2000 (MarsHydro 300W) at 24" and about 25%. And circulating air in those cups will replenish CO2, discourage pests and problems, and strenghten the stem.

If I were you I'd raise the light and turn it down, then cut that top lip off with some scissors so a fan can push a bit of air across them.

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Thanks so much for your input. Especially relevant since we have very similar lights.

I'm going to adjust light as soon as I get home. I already adjusted the fan last night.

The light was my very first concern when I started this grow. I asked around and ultimately used the manufacturer's recommendations.

cachexic said:

Thanks so much for your input. Especially relevant since we have very similar lights.

I'm going to adjust light as soon as I get home. I already adjusted the fan last night.

The light was my very first concern when I started this grow. I asked around and ultimately used the manufacturer's recommendations.

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Mine stretched a bit more than I wanted at that level. If I did it again with the same strains, I would turn it up to maybe 30%. But always listen to the plants.

Nutrient blend started at 400 EC for seedlings and have been gradually increasing per a guide I'm following. The oldest seedlings are up to 750 EC, with the two youngest taking 500 EC at their last fertigation.

I would throw the guide in the shithouse, they would need next to nothing as far fertiliser, should never have increased. Said you’ve charge the media up in cal mag at 150%?

I think they are dying in nitrate

Fruity420 said:

Nutrient blend started at 400 EC for seedlings and have been gradually increasing per a guide I'm following. The oldest seedlings are up to 750 EC, with the two youngest taking 500 EC at their last fertigation.

I would throw the guide in the shithouse, they would need next to nothing as far fertiliser, should never have increased. Said you’ve charge the media up in cal mag at 150%?

I think they are dying in nitrate

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Yeahhh... I'm starting to come around to that...

I think you're supposed to ramp up the EC provided the plants are showing good growth, not when they are in trouble like mine are. I'm going to back it down to 500 EC and try and salvage this mess.

Thank you for weighing in.

JimmyJackCorn said:

Mine stretched a bit more than I wanted at that level. If I did it again with the same strains, I would turn it up to maybe 30%. But always listen to the plants.

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I will at least raise it up to 18" from 12"

It’s very common when starting out and very easy to over do fertiliser, all these exciting new bottles and who doesn’t want to speed things up.
A new seedling will be fine in completely inert, unbuffed coco or any medium for its first few days, needs nothing at all. After it’s first set of leaves have formed it will need very low levels of fert.
The need for extra calcium and magnesium is often exaggerated, sure they’re absolutely required but when the plant needs virtually nothing in the first weeks, loading excess calcium magnesium nitrate into coco can do more harm than good

Fruity420 said:

It’s very common when starting out and very easy to over do fertiliser, all these exciting new bottles and who doesn’t want to speed things up.
A new seedling will be fine in completely inert, unbuffed coco or any medium for its first few days, needs nothing at all. After it’s first set of leaves have formed it will need very low levels of fert.
The need for extra calcium and magnesium is often exaggerated, sure they’re absolutely required but when the plant needs virtually nothing in the first weeks, loading excess calcium magnesium nitrate into coco can do more harm than good

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That makes sense. I suspect you're right.

Hopefully I haven't squandered too much time in the early seedling days (as these are autos) and can still finish this with a satisfying result.

All the best bro, you’ll be better from the experience and still plenty of time to get them finished nice

I second fruitys approach. Solid advice

Just an update: I made a huge mistake in the very first two days of seedling phase and gave my plants full strength nutrient blend (I didn't realize my TDS meter reset to PPM every time it turned off....yeah...).

So I flushed them and started giving them the correct EC, but following the Dr. Coco guide I was still increasing EC +75 every fertigation. I don't think I ever gave the seedlings time to recover from the blast of 1000+EC full strength blend, though, and their root zones were way too high EC given how small and undeveloped they were.

Taking the advice of some of the helpful growers on the internet, I flushed the plants back down until runoff was about 600 EC, then began feeding them 600 EC blend with no rampup. I also placed them in a humidity dome to raise RH to 60-70%. After just a short while they seem to be back to growing. I hope I didn't do a huge amount of damage for the long-term health and yield of these plants, though I fear I did. I'm going to just press on and see what happens.

Attaching some pics of how they look now. I think 3 or 4 of them are close to being potted up to the 1-gallon fabric transplanter pots. They have sprouted third node and there are quite a few roots coming out of the side and definitely bottom of the fabric pots. I'm going to wait another day or two then pot them up, and at that point I'll start incrementally ramping up EC.

Lowkeygardener said:

Looks like your young leaves are shying away from your light. This early on you could get away with around 26 Watts of CFL per seedling. 40% of your 300 watts at 12” away seems like overkill to me. Raise your light significantly until you start seeing some stretch then adjust accordingly until you find that sweet spot.

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Well shit, this is exactly the answer to *my* question. Thanks!