Trouble ticket for stunted plants

What is the strain? Northern lights auto
Indoor or Outdoor? indoor
Size of space? 4x5x7
PH 6.5 max
Type of nutrients used? PPM levels? pH water only
Temperature? 68-78F
Humidity %? 38-51
Light system/watts? CFL - two fixtures w/six 25W 6500K each, LED - two fixtures Viparspectrum 450PAR (210w stated draw)
Vegetative Growth season or Bloom/Flower season? Still in seedling.
Number “weeks/days” from start of veg growth or into flowering? 15 days from sprout.
The pictures were taken at 13 days. Seedlings kept under domes and misted for 7 days after sprout under cfl. Led turned on @50, then 80, now at 100% white and blue plus cfl. Began watering 500mL pH water each plant every other day. Seeds started in 5gal cloth pots and remain there. My next watering should be today, but I have almost decide to skip this watering and begin fertilizing with FF Trio per recommendations, 1quart/plant before starting over.

I think they’re too small for much water and if it were me I’d wait on nutes until they’re established. What soil are you using? It may be “hot” and holding them back.


I think just the opposite. I intentionally purchased soil that had no added nutrients, so I’m thinking that may be what’s holding them back. As to the water volume, these are in 5 gal pots so the volume I’m adding now (actually 250 instead of 500mL) is being dispersed throughout a large volume of dirt and I’m feeling it dry out quickly. I have seen no runoff. Would you agree these plants are below average growth for their age?


They are small I agree. Good choice for the soil! There is enough on board nutrients in the cotyledons to carry them.

I had a slow start to some seedlings in coco because I thought I could ph a larger volume of water and use that without continually adjusting ph. Wrong!

If the root zone is wet that will stall it.
If the ph is off, same.
Soil too hot: ditto.

Have you checked the calibration on your ph meter?

I promise you that if the soil is mild they should be fine. I use coco which is nutrient free and I don’t feed for 3 weeks.

Good question on the pH meter. I bought one of the cheap yellow things from Amazon and calibrated it with the buffers included with the meter. I also use some strips and the solution from the pH UP-DOWN kit. None of these match so I got some standard buffer solutions and turns out the cheap yellow meter from Amazon was the most accurate. The strips all read low and the solution is a guessing game for accuracy. I keep pH 4, 10, 4.1, 6.8 and distilled water to rinse with after using. I check the meter each time before testing my water. My water is hard from the tap with about 210ppm and 7.2-7.6. I let it sit in an open 6gal bucket in the grow room. I have to adjust the pH down each time I use it and try for 5.8-6.3 for watering.

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Now for a slurry test just to see what your soil ph is.

Take equal amounts of soil and distilled water and mix together and let stand for 30 minutes then check the ph.

You’re right: strips and drops are tough to use.

I can do that. Equal amounts by weight. I’ll have to get soil near the outside of the pot so as not to disturb any roots. Is a handful enough?

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I think 3 or 4 tablespoons would do it. Try to get the sample near the root zone if possible. You may have some wonky ph in that soil which has your sprouts outside their nominal range and it’s stunting them. Maybe not; but it’s worth the exercise.

I’ll do that when I get home tonight. I’m guessing the remedy for a pH wonk is flushing and I don’t know how to do that. Isn’t that risky? Of course I’m contemplating starting over anyway so six of one…

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Don’t start over. I think they will recover (unless they’re autos). You might want to pick up some FloraKleen or Sledgehammer which reduces the amount of water needed to properly flush the soil. I wouldn’t do anything until you know what you actually have.

Normally 3 times the pot size in water poured through gradually is the ticket. PH it to your nominal value unless trying to drive PH up or down within your range. Sometimes soils are way low or high and it’s a tossup between transplanting to good soil (not done for autos) or manipulating the PH to bring it in range.

You mentioned that your water is hard at 200 plus ppm. I’m jealous! Mine is 500! I use it too and don’t suffer any noticeable ill effects. Although I don’t need much cal mag lol.

I would not flush. They seem stunted to you because most of the work is happening at the root zone.

Usually flushing is only done to remove nutrient build up. You don’t need that since you said the soil has no added nutrients. The other reason would be to try fixing pH that is way off. Do the slurry test before doing anything else.

Don’t want to unnecessarily subject them to an overabundance of water…


@Myfriendis410 @FloridaSon Yes, they are Autos. I’ll do the slurry and post it up. I realize the roots have to do their thing but I’m comparing my pitiful little seedlings to others here of the same age and strain with obvious frustration. Thanks.

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LOL! Yeah; imagine flushing 15 gallon pots! I’ve done it.

Just saw your edited post too. I put in the caveat on autos because the consensus is to leave them in their forever homes to avoid stalling and if these don’t improve you are right to start over. One of our forum members grew an auto that stalled out and he harvested just about a joint’s worth of weed from it haha! It was cute!


Your in five gallon pots until the root system fill it out they will look like no upward growth is happening or very Little
I use 2 gallon pots fir my autos 3 at most
I bet they take off in the next week or so
I wouldn’t feed just yet


I dropped my Blueberry autos 2/22 and they are still tiny as well…

I’m glad your other ones are living up to your expectations, but they tend to start slow because of all the space for the roots to grow.

May be different phenotypes…


@Countryboyjvd1971 @Myfriendis410 @FloridaSon are giving good advice…need to measure pH of soil.

Also, just a point of reference, while mine are Gold Leaf and White Widow photo period plants as opposed to your Northern Lights Autos, your plants are barely smaller/behind than what mine were at that stage and they are now doing very well (at least I think so - first grow) at nearly 6 weeks and around a foot or so tall, very bushy.

As mentioned by @Countryboyjvd1971, your plants may just be forming a great root structure to support some rapid growth in a week or so. Good luck with this and be patient.:+1:


I start in rapid rooters, then pop those into peat or cow pots, then pop those into soil. For autos, this worked as well as it does for my photos, with the added bonus of protecting the fragile root zone when I had to flush my autos’ hot soil at only 14 days from seed, after transplanting them into 3 & 5 gallon pots.

I wouldn’t recommend flushing such young plants, especially autos, though. I got lucky, b/c of my peat/cow pots. I’d probably have really stunted them or killed them, otherwise.


Autos definitely add a new dimension to the growing art lol. I agree that flushing is far from ideal at this stage to say nothing of the seedlings having to deal with a saturated five gallon pot for an extended period of time. I would either start over (not ideal) with new soil but do nothing until you have data on the existing soil. You have some experienced auto growers who have weighed in so I’m watching!


Exactly my thinking large pots and roots spreading hard equals low top growth


Results of soil slurry pH test:
I have 3 plants sample 1 is the largest, 2 is mid, and 3 is runt. I collected 50g soil from 3” deep and tried to get the moist soil toward the center. I needed 150g of dwater to make a good slurry. Let sit awhile. I rinsed my meter in between measurements in dwater.

I’ll let the samples sit a bit longer and re-measure.