Seedlings curl up and die off

From a fellow grower: Purple Kush (Auto) - germinated 2 days and grew 30 days, then curled up. I use Fox Farm soil and Humbolts best

Welcome to the forum. A few bits of info will help us diagnose your problem.
Just like a visit to the doctor who asks several questions before prescribing treatment we just need a few detail before we offer advice.

Answer these simple questions the best you can. If you are not sure, just bring it to our attention. We will figure it out.

  1. Indoor or outdoor? - size of grow?
  2. Origin of seeds?
  3. Regular, feminized, or autoflower?
  4. Origin of water. PH, EC/TDS of source water?
  5. PH and TDS/EC of if mixed solution?
  6. Grow method? Soil, Soil-less, Coco, Hydro, Aquaponics. Please explain.
  7. Nutrients or fertilizer system used.
  8. What type of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate.
  9. What are the temps in your grow space? Day / Night?
  10. What is the RH = relative humidity in your grow space? Day / Night?
  11. AC, Humidifier, De-humidifier?
  12. Do you have a Ventilation system? Size? 4", 6"?
  13. Co2 Yes / No?

Usually overwatering is the culprit. Root rot comes to mind. I also generally just hate plastic containers for cannabis. Promotes all the bad things like water retention and lack of oxygen.

If we can get OP on the forum, we can likely help out more.