Why are my seedlings growing so slow?

When they are this small you don't really need an exhaust fan running all the time. I would set up the exhaust fan on an inkbird temp controller so it kicks on at 30.5 and off at 28.5. Also make sure you've got a circulation fan running 24/7. Get an inkbird humidity controller and run a humidifier to get RH up to 75.

Water with and 1.5 - 3 litres or enough to wet the entire pot at 70 percent strength nutes every 3 or 4 days.

Seedlings don't need much light. You can run your light on 25% and have it at about 2-2.5 foot from the tops of the plants. If you have vigorous genetics and they want more light they'll start to stretch. This is the best indicator to use for gauging when to up the light strength.
 
You don’t need to start in a final container that size. Pot up. Each watering brings fresh oxygen/nutes and a growth spurt.

When they are that young they don’t even need extraction. Simply opening the tent once or twice a day is enough
Thanks I was thinking that so I've switched the extraction & intake system off until I think they should be on
 
If those are 19 days from breaking ground I wouldn't waste anymore time on them . Just start over .

A newer grower did that which I suggested try seeing it through and theyre way into flower now. Ended up being a good move. Mine looked good recently for two weeks in more horrid conditions. Yea I just looked again those are pretty stunted. Sadly Id start again if you dont want to wait another month.

I might have to do that to a clone but its way into the keep me just give me a sec phase. Its got time but we will see. All my cuts came from a stunted clone.
 
Your temps are too low. they should be between 24c and 26c at this stage

Your humidity isn't bad but it could be slightly higher. Around 70% - 75%

it seems like you are growing in coco and pots those size are too big for seedlings. You should start off in smaller pots next time with perlite added to the coco. I recommend a 70% coco mix to 30% perlite.

If you are in coco I suggest for you to let that coco dry out in between feeding and not water until run off daily yet since they are pretty big pots to start off in and feeding daily in those pots will probably starve the plants of oxygen at the root zone and prevent the roots from growing and give you very slow growth rates.

25% on your led light is fine at this stage, they are already stunted and stressed as it is so I wouldn't think about adding more light at this stage. I would think about adding a 135watt 3 foot tubular heater to your grow room to keep your temps up though, you could use a wifi controlled inkbird temperature gauge hooked up to the heater to keep the temps within range, just make sure you hang the sensor part of the inkbird sensor up inside of your tent so you get accurate readings.

inkbird temp gauge link https://www.ebay.co.uk/itm/254540121141 & tubular heater link https://www.ebay.co.uk/itm/388007222780

If you have any questions please don't hesitate to ask me.
 
Last edited:
Oh no so I should lower it a few inches downwards :/?
Perhaps but my hunch is that light levels are well down the list of issues.


What is different about this grow than your previous grows?

When you wrote "on day 19 " - when did you start counting days?



Re. what to do with the light.

The underlying issue is that I don't have a PPFD map so I can't do an accurate estimate of how much light your grow light can generate. If you find a PPFD map, post the link and we can figure it out.

Note PPF≠PPFD. PPF is the amount of light a fixture can generate. PPFD is the amount of light falling on a square meter in one second, as measured at a specific height.

Another approach would be to go by the manufacturer's recommended settings. In many cases, they're good numbers. Check the manufacturer's web site for that.

Finally, I don't think that light is the issue so LTFA could be the best approach.
 
Perhaps but my hunch is that light levels are well down the list of issues.


What is different about this grow than your previous grows?

When you wrote "on day 19 " - when did you start counting days?



Re. what to do with the light.

The underlying issue is that I don't have a PPFD map so I can't do an accurate estimate of how much light your grow light can generate. If you find a PPFD map, post the link and we can figure it out.

Note PPF≠PPFD. PPF is the amount of light a fixture can generate. PPFD is the amount of light falling on a square meter in one second, as measured at a specific height.

Another approach would be to go by the manufacturer's recommended settings. In many cases, they're good numbers. Check the manufacturer's web site for that.

Finally, I don't think that light is the issue so LTFA could be the best approach.
What was different about the other 2 grows I was using a 600w hps light which offers plenty of warmth problem was using it during a summer heatwave was a real battle I couldn't extract it correctly like I can today... Lesson learned however I kept hearing about how the leds make controlling environment much easier especially during the summer months .

I started counting from the day it sprouted

Ye that's strange no information about it dunno why? Tho I'll try to find out the ppfd hopefully get back to you thanks
 
I Suppose so I'm growing in a 1.2 +1.2 2.0

Would a heater not dry the plants out tho :/?
Raising the temp will lower humidity but it needs to be done. Most growers need both a humidifier and dehumidifier at different stages during a grow. When I first started I added my crock-pot for some heat and hung wet towels in the tent to raise humidity. I'd try to get temps up to the upper 20's.
 
Last edited:
Back
Top