Rust Fungus?

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All of a sudden both my LSD planet s are getting hit with something. The Scooby, right beside them, seem to be okay. Does this look like rust? What is it and what's my cure? DCE4B612-DD5A-470A-8167-C13513D06E5C.jpeg

Hi Brian, that looks like calcium deficiency which is quite common in cannabis. It usually shows itself in late veg/ early flower when the girls are feeding heavy. A good weed fert will have at least a 2:1 calcium/magnesium ratio. Very important at the beginning of the season.  The cause can be soil pH, calcium content of the soil and/or high phosphorus in the soil.  Certainly not the end of the road for the plant. You can ride this out with some slightly reduced yield, but it's a bit hard to fix at this point in the outdoor season. No foliar feeding at this point either if flowering has initiated.

For a quick remedy, you can go to the garden center for some soil lime (Epsoma Garden Lime is still available at garden centers), follow the general instructions. Another remedy is Ultra Tums tablets which contain 1000mg calcium carbonate/tablet (40% free calcium) Two tablets dissolved in pH 6 - 7 water gives approx. 200mg/L free calcium (200ppm) and this is a relatively quick fix also. Either method will give a bit of improvement before harvest.  This is not a major problem at this point, but now you know your soil will need a boost next spring. Btw, your plants look beautiful overall. Nice job and enjoy your harvest! 

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https://www.espoma.com/product/garden-lime-3/#toggle-id-3

Thanks Joe, greatly appreciated! I discounted the calcium deficiency because I've been adding a cal/mag to the nutrient mix. Should I increase the cal/mag, or do the Espoma and/or Tums?

>>Should I increase the cal/mag, or do the Espoma and/or Tums?

If you are using a high phosphorus flower fert at this point and adding cal/mag to the nutrient mix, the calcium gets tied up with phosphorus and becomes unavailable to the plant (calcium phosphate which is water insoluble).  Don't add cal/mag to any other fert solutions. Use the cal/mag by itself in a completely separate watering and you should see some improvement.  Sounds like your doing all the right things. 

Again, this isn't a major problem at this point and you are still going to have a great harvest.  When the soil is deficient or the nutrients are locked,  the fan leaves will be the first to show the calcium deficiency because flower production has started and calcium, if not available by roots, will be pulled from fan leaves to feed the all important flower which is the only reproductive structure the plant has to continue its survival by (wishful thinking for the plant) producing the all important seed.  Happy growing!!!

 

You're The Man, Joe. Thanks again. It all makes sense. I just started adding the flower nutes, and bam, the spots appeared within a week. I'll maintain the same levels of nutes, but do the cal/mag separately. Would it help to increase the cal/mag, or even temporarily decrease the flower nutes?

You're very welcome, Brian. I'm not sure where you live but your plants look like they are in early flower. I am not an experienced outdoor grower, but I have always had good luck indoor with fertilizing on one watering and then pH adjusted fresh water the next watering. I would not increase the cal/mag or decrease your nute feeding just yet. Your plants look nice and healthy; they don't look overfed. Just follow the nute bottle instructions and keep the cal/mag supplementation seperate and all should improve. More is not better in the fertilizer game. We try to force too much on a plant, all in good faith, but plants are much like humans/animals in the respect that if we are fed too much/too little, we become sick in a variety of ways. Balance is always the key and, to that end, moderation always wins. 

My experience from indoor is to drop to half strength flower fert on week 4 of flower leaving the last two weeks for fresh water only (using 60-66 days of flower as a guide), however, I will defer to the outdoor experts here for decreasing feed into late flower outdoor, though.  I hope you are healing and you and your family are doing well.

Thanks again, Joe. After a nice flush, then a blast with cal/mag, they are stabilizing nicely!

Awesome! Well done, Brian. Happy harvest!!!