Hi lifesagardendigit ,

I see the plot pretty well, as I have observed the same thing with my basil (actually mostly with Italian style, Valentino etc.) I haven't got any plausible explanation for it either, except the vigorous growth of basil, which may lead to this "weakness". Perhaps some immobile elements may not follow the growth. Basil seems to tolerate fluctuations of nutrients and PH change pretty well and thus it's hard to search within those parameters. I also thought of insufficient drain, but some of the plants seem to not be affected by high humidity of the substrate.

I am not sure if transplanting deeper will help. Perhaps lower nutrient concentration may be worth a try, as this will give the plant time to strengthen the stems. The most pragmatical (although kinda unorthodox) solution would probably bee to grow more plants anyway and eliminate (consume) those with the stem problem earlier. ;-)

It sounds to me like the crown is too wet. Would it be possible to raise the affected plants mabe 1-2 cm so the top of the media doesn't get wet directly from the nutrient (i.e. it gets moist from capillary action).
I had a similar thing happen to me a few years ago growing peppers in a EnF system where my overflow was too high and it kept the crowns too wet.

thanks for the thoughts lucas and grizz... i thought that it might be a wet crown too so i might ex. more with different depths... lucus i think the eliminate process will definately be the direction at this point.. thanks again!

Soil growers call this "Damp-off". It's caused by letting the stem get and remain wet. The dampness allows a fungus to form and eventually the whole plant topples.

Less water on the stem and perhaps a little fungicide will fix things up.

I also think blowing a fan on them from early on might help. I think if you start off with a stronger stem, they'll be less likely to flop. If you're ripping them out anyway, you might experiment a little-- If you pull them out of the hydro system and let them wilt and almost die, then put them back in, they may develop a brown, woody stem. My outside herbs do this when stressed, and it's very sturdy. Or you could try supercropping, maybe?

I know this is an old post but seeing as I am having the same issue and found this forum others will as well. I just wanted to add that I have had air on mine as early seedlings and this did not resolve the issue.