Problems with my marijuana plants

A question from a fellow grower:

having trouble with all the plants growing at present. the appearance of the plants looks like heat stress, leaves curling in along the edges. they are all growing indoors from cuttings to about a foot high, then they are put outside where they usually do very well.
now the leaves most affected are the young ones, they are curling up as they form. the older leaves look virtually unaffected.
we wondered if the plants, being all clones, may have been getting to the end of their natural life. but we planted out about a100 seeds which all took, & initially were looking good.
2-3 weeks later they too are taking on the appearance of all the earlier affected plants.
the plants are all fed well, not overfed. deficiencies are seemingly not the problem.
BUT! poisons have been used around where the plants are located,(metsulfuron methyl-----triclopyr------picloram) to be specific.
it is well & truly in the soil all round the place of early growth. but has never been actually sprayed around the same area. apparently the soil was placed around the growth area, & the soil was saturated with the stuff.
the air intake fans are very,very close to the soil, & we are wondering if gas off from the soil might be doing the damage.
are you able to enlighten us to the problem/causes? and are you able to give us advice to correct the situation?
all the above details, re poisons etc, are just our thoughts on what it might be that’s affecting our plants. we aren’t positive about it, it’s almost the only thing we could come up with after weeks of thinking about what the hell was going on with our plants. and then the new seedlings all started curling up as well.

You say you have never had a problem, but go on to say your ground is poison.

You say you are outside, but mention ventilation gabs close to the ground. What does that mean? If you are growing in a teen in high temps, and ventilating from the bottom, then you leave all the nasty radiant heat in the top

Many questions.

Temps? Yuo say it is hot???

Ferts? You say you are fertilizing them, but correctly. How? With what?

thank you both for your questions.
the plants are being raised in an enclosed environment.
air is drawn in via fans, & hot air exhausted the same way.
the plants are all taken as cuttings from older plants,& placed in growing blocks after immersing their end in a growth promoter.
this procedure has been followed for a decade or more, with very good results.
when the plants get to about a foot high they are replanted in an outdoor environment, where they then begin to mature.
total indoor growth & maturity has not been a success.
where the air is drawn into the chamber, soil has been placed as cover,& as ridges to drain water away from the growing chamber.
this soil has been contaminated by the afore mentioned poisons.
my question to anyone is; can the soil retain residue of the poison over an extend period & gas off, to then have the gases drawn in with the air, & then affect the plants in a very subliminal way?
the plants aren’t dying. but they are ending up quite stunted. even after they have been put out, they never fully recover. they do seem to get a bit better, but they never attain the vigour that they usually have.

Depending on all the particular ingredients in an herbicide; Some will ruin the soil for future use; Or, for an extremely long period of time. Other Organic fatty acid based herbicides can be used with a minimal wait time of 2-3 weeks.

Some recommendations for herbicides may instruct that you cannot use hits on any vegetable garden or pasture where cattle, etc, graze.

Best thing for you to do; Get the exact make and label name. Search online ofr that exact product. That is what I do before using “Crossbow” or “Scythe”; 2 Organic broadleaf herbicides.

In closing; I would say; "Barring any other variables, between last successful growl And, this one. I owuld think it is attributed to the poison. Contact the company and ask if you can plant or grow in the environment created in your space. Peace

On the other hand; If you are in Colorado, and you are legal MMJ grower…I wouldl call your County agent and ask him.