I am growing Sticky Orange XXL Auto, but I keep running into issues during the seedling stage. Around Day 10, the seedling completely stops growing.

I am using a premixed potting soil blend (approx. 64% Coco Peat, 15% Peat Moss, Perlite, Vermiculite) which already has a base EC of ≤ 1.2.

Currently, I have been watering with a pH of 5.8–6.0. The light level is around 200 PPFD, and ventilation/airflow is good. However, growth stalls entirely at this point.

Could the lower pH (5.8–6.0) or overwatering in this peat/coco soil mix be causing nutrient lockout and root stagnation? Any advice would be greatly appreciated!

First of all, welcome to the community @Tamashi . Your pH value is set well for coco coir, and the PPFD is fine too. How often and how much water do the little ones get? What is the humidity level, they need about 75% since at the moment they absorb water almost exclusively through their leaves. Keep in mind that you need to add CalMag to the water as it gets stripped by the coco. You should also start fertilizing quite early when growing in coco coir.

I’m not exactly an expert on growing in coco, these are just the things that come to mind right away. I’m sure someone with more experience will chime in. @Demonrage75 @Crackadoo maybe

Thank you for the warm welcome and the helpful suggestions, @herr_gruen!

Actually, I just checked my medium bag again and realized a critical mistake on my part: I am not using pure coco coir!

It’s actually a premixed potting soil blend (approx. 64% Coco Peat, 15% Peat Moss, Perlite, Vermiculite) with a base EC of ≤ 1.2 and a soil pH range of 5–7.

Watering frequency/amount: I was watering a small amount around the stem every 2–3 days.

Humidity: Currently sitting around 55–65%

It

always stalls in the exact same pattern—the leaves just stop expanding.

I’ve wasted so many seeds from these back-to-back seedling failures…

When it’s a seedling, the plant focuses on growing roots, which is why you don’t see changes, and it could be a critical biological stall due to root suffocation and lack of light

if you haven’t grown much, I would tell you to relax, and that it’s normal: after a few days, seedlings “stall” because they are colonizing the substrate with roots; once that’s done, they start growing vigorously again.
if you think this isn’t the case because you’re already used to growing, let us know, but if you’re new, it’s probably just the roots colonizing the substrate

Thanks for the reassurance, @loveweed and @3xt3nd3d!

I know it’s completely normal for seedlings to pause top growth while focusing on building their root systems. However, in my case, the leaves don’t just temporarily pause—they completely stop expanding at Day 10 and eventually die without developing further.

Wow, how terrible! To be honest, visually there’s nothing that looks like they should die, have you ruled out overwatering? Maybe it’s a genetic issue, but the roots could be rotten, the EC seems really high to me for a seedling, those are flowering stage ranges.
Are these the same ones from the photos? Or is it a second batch?

To explain my situation a bit more, I’ve actually been growing successfully for 5 years without any issues, but recently I’ve hit the exact same wall several times in a row, which is super frustrating.

This isn’t just a normal pause where top growth slows down while the plant focuses on establishing roots. The leaves completely stop expanding at around Day 10, and the plant stalls completely until it eventually dies.

Have you grown with the same substrate? Or have you changed it, I’m very intrigued by the drooping of the leaves.

Same genetics? Have you ever grown those genetics successfully? I mean, are you familiar with them? If so, maybe a virus?

As @3xt3nd3d says, it could be due to salt toxicity

I actually changed the substrate for this run. I thought my previous failures were caused by using a medium that was too hot (too rich in nutrients), so I switched to a milder one that’s supposed to be suitable for seedlings. But unfortunately, the exact same issue is happening again.

I actually thought salt build-up might be the issue as well, so I tested it, but the EC/salt levels turned out to be totally fine.

Even if the packaging says it’s a light substrate, many commercial batches come poorly washed from the factory and saturated with electrical conductivity (EC) that is lethal for microscopic roots on day 10. The seedlings suffer reverse osmosis: the soil is so salty that it sucks the water right out of them, dehydrating and scorching the basal root hairs (that’s why your leaves are drooping like an umbrella).

On top of that, coco coir and peat in such large pots retain too much stagnant water around the stem, stripping all the oxygen from the soil and causing root asphyxiation combined with salt buildup.

If you want to save the grow at the last second, apply this immediate laboratory rescue protocol:

1. EMERGENCY ROOT FLUSH (Flush): You have to put those pots in the tub and water with three times the volume of pure water (ideally reverse osmosis or settled water with pH adjusted to 6.0) until it drains out strongly from the bottom. You need the water to run freely to drag out and physically ‘rinse’ the excess salts accumulated in the substrate, bringing the EC down to safe levels.
2. STRICT POST-FLUSH DRY PERIOD: After flushing, the pot is going to be super heavy. Do not water again for the next 6 or 7 full days. Set up fans to continuously move the air so the soil dries out deep down. Damaged roots need to breathe pure oxygen (O₂) to heal and get moving again.
3. FAN AND BRING LIGHT CLOSER: Move the light a bit closer to stop stem stretching and turn on continuous subtle background ventilation to thicken up those skinny stems. This is what artificial intelligence led me to understand, hopefully it helps you out, give it a try.

I’ve had 4 to 5 consecutive failures, and I’ve been testing with a different strain/genetics each time. Every single one successfully germinates and sprouts cotyledons, but after about Day 7, growth completely stalls across the board. So it doesn’t seem to be a specific genetics issue.

The photo is actually of my second batch.

As for the EC, I checked the runoff, and it came out to pH 6.2 with around 300 PPM (EC ~0.6), so the EC levels don’t seem to be the problem here.

By taking food out of the equation, botany and physics leave us with a single, immutable truth: your plants are frozen on day 10 due to Chronic Root Suffocation caused by mechanical compaction.

By using a mix loaded with 64% Coco Peat and 15% Peat Moss straight into such gigantic pots for seedlings that are only a few days old, the soil sets a trap. Even if you water “a small amount”, that dense mass of peat absorbs water like a heavy sponge, compacts in the center, and eliminates all aeration pores. The microscopic roots ran out of pure oxygen (O₂). Unable to breathe, the underground engine enters a coma, the plant loses upward hydraulic pressure (which is why the leaves don’t expand and droop like umbrellas), and growth stops 100%.

To break through the wall and save the grow right now, apply this zero-cost physical rescue engineering:

1. SEVERE AND ABSOLUTE DRY SPELL (Zero Water for 6 days): Put away the sprayers and watering cans. You need that dense mass of peat to dry out completely and evenly. The soil needs to dry to a crisp so the pores can naturally fill with fresh air again.
2. AERATION POKES WITH A SKEWER: Grab a thin wooden stick (like a skewer) and make several subtle yet deep pokes in the soil, away from the central stem. This physically breaks up the compact peat crust and channels oxygen directly into the root zone without damaging them.
3. 24/7 LOWER VENTILATION: Place a fan moving air toward the pots to speed up surface drying and force the roots to wake up from their suffocation coma.

When you are watering are you adding any nutrients at all? An ec of 1.2 makes it seem high but if that isn’t anything that the plant is wanting right now it isn’t going to help much. Im feeding from the first watering in coco and never give plain water at any point of the grow