Please help these Northern Lights Autos!

Some of my plants leaves are starting to form yellow and rust colored spots!! I have seen lots of people in other threads diagnose similar issues to a CalMag deficiency but my leaves seem to look a little different so I wanted to consult the experts within the forum before feeding my plants something they do not need!!!

These are Northern Lights Autos currently in week 9 since sprouting! They are planted in 5gal pots of FFOF. I currently water as needed at a PH of 6.5 (which seems to be about a half gallon each every 3-4 days). Two weeks ago I gave my first feeding of Tiger Bloom at 2.5ml/gal for the both of them. Then last week I gave their second feeding of Tiger Bloom at 5ml/gal for both of them. I spray the plants weekly with Pure Crop 1 and Monterey B.T.

Please advise on what you think these ladies need!!!

This will help with posting pics

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Thanks for the tip, pretty sure I tried to upload too many pics at one time!

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All the lil specs are concerning. You check for bugs?
Its common for lower and older leaves to yellow during flower.

This flow chart best diagnostic tool in my arsenal.
Dont think its calmag. Calmag presents as rust colored spots those spots are more yellow.

Yes those spots appeared while I was away on a week long vacation. More concentrated doses of peroxide and Pure Crop 1 have seemed to stop the spread and eradicate whatever was causing them!

And that diagram dose seem like a great tool, if you know how to read it properly…lol I am by no means a biology or cannabis growing expert! What would you suggest from the posted pics??

Its a flow chart. Yes and no questiond, with a few very googlable terms. Botany degree not required.
Asfor your plants, yellowing normal lower leaves. Being in flower and bugs accounted for. Id say she is hungry. Thats why she is consuming her stored nutes. Could be an issue with soil ph if she has been fed. Be good of you to fill out this support ticket.

COPY/PASTE the below list into your forum post.

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

  1. Indoor or outdoor? - size of grow?
  2. Otigin 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 typr of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate.
  9. What are the temps in your growspce? Day / Night?
  10. What is the RH = relative humidity in your growspace? Day / Night?
  11. AC, Humidifier, De-humidifier?
  12. Do you have a Ventilation system? Size? 4", 6"?
  13. Co2 Yes / No?
  14. How long have you been growing?
  15. Runoff ph snd tds
  16. If you grow hydro, then please explain your hydro method. DWC, R-DWC, Ebb and Flow, Or; Other? Other?

16b. Size and temperature of solution in reservoir?

Always try to upload a clear picture in white light of any issues you may have to allow the community to identify your issue.

Anything you feel would help us give you more informed advice should be included. Feel free to elaborate at the end of the survey.

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  1. Indoor or outdoor? - Outdoor, 2 plants

  2. Otigin of seeds? Northern Lights Auto from Seedsman, currently in week 9.

  3. Regular, feminized, or autoflower? Autoflower

  4. Origin of water. PH, EC/TDS of source water? Tap water PH’d to 6.5

  5. PH and TDS/EC of if mixed solution? Not tested

  6. Grow method? FFOF Soil

  7. Nutrients or fertilizer system used. Only fed Tiger bloom twice: 2.5ml/gal last week, 5ml/gal this week.

  8. What typr of lighting are you using? Natural Sunlight

  9. What are the temps in your growspce? Outside temps have been 85-95F Day, 75-85F Night.

  10. What is the RH = Very sporadic being outdoors, 60-95RH Day and Night.

  11. AC, Humidifier, De-humidifier? N/A

  12. Do you have a Ventilation system? N/A

  13. Co2 Yes / No? N/A

  14. How long have you been growing? First Grow

  15. Runoff ph snd tds: Not tested

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Its super important to ph your nutrient solutions.

This graph will show you why, some nutrients get locked out if not in range. This is the likely issue causing your yellowing leaves.
Easy fix, just ph your nute solutions.

Yeah so especially now as she stretches and blooms increase to full feeding. 10ml/gal. Tiger bloom is only part of the needs. Here is a screengrab of my last feed so you can see what I mean. While you dont need all the stuff I use you will need to give her enough N-P-K value to grow or she will eat up her stores and yellow off leaves which will then die (necrosis).

So thats my answer, ph and increase feed.
I recommend to keep track of runoff figures, its super helpful in telling you not only if you have lockout but also when to feed more and the quantity that she is consuming. You can also remove any leaves that are yellow and or dead. She will waste energy trying to repair them and never succeed.

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My answer would be the same.
@Docnraq has got you covered.


This was very helpful, thank you! Not sure why I assumed they would be okay only using Tiger Bloom until harvest…

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FFOF has a fair amount of nutrients in it, usually gives out around mid stretch early flower (which is where you are at), with autoflowers anyhow.

You can make it on just TB but you will wanna give her more then 2.5-5ml/ gallon. Closer to 20ml/ gal and even that is a fairly light feed. If you can get yourself the others in the liquid trio, Big Bloom and Grow Big. If not start giving a bigger dose of TB start at 15ml and go from there. Your tap water will cover your calcium and magnesium and other minerals. Ive found silica is a helpful nutrient additive. Outside of that yellowing, they look good and healthy. I grew some seedsman NL, great smoke!

Okay thanks for the great advice! Im gonna see if I can get away with only utilizing BB and TB starting with Fox Farms week 10 recommendations of 3tsp BB and 2tsp TB.

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