Brown spots on yellow leaves starting from leaf tips

Troubleshooting
, ,
1

Hey all! Brand new grower and am absolutely CAPTIVATED by it!!! Up to this point, I’ve been able to remedy just about every problem with sufficient research but I’m stumped now.
I’m basically losing my plants it seems. It started to appear on my bigger lady first. Brown spots and yellowing leaves popping up seemingly randomly on the plant and now spreading to the entire thing. PH started dropping and I found it at 5.1. Flushed and and flushed and flushed and was finally able to get a reading of 5.8 this morning. At first feed.
Second plant started showing signs about 2-3 days ago. Now is getting worse as well although the PH is not dropping.
I water to waste about 20 percent 2-3 times per day.
Also leaves on top are turning purple.

IMG_3760
IMG_37601512×2016 1.92 MB

IMG_3761
IMG_37611512×2016 1.27 MB

IMG_3763
IMG_37631512×2016 1.17 MB

IMG_3762
IMG_37621512×2016 1.42 MB

IMG_3765
IMG_37652016×1512 1.76 MB

Worth mentioning. I thought I contracted root aphids early in veg and started treating with botanigard wp. I saw a positive response from all plants and continue to treat.

Also, I got tired of paying for distilled water and bought an RO filter. I PH adjust every feed though and test ec. Plants have been unable to tolerate ec over 1000 with no burn entire lifespan.

Third. I see algae growing on top of the coco. Also on the side of the bags.

I’m trying to research all solutions here.

Is it root aphids making a comeback except I find zero trace of them at all?

Is it soft water causing low root zone PH?

Is it algae somehow growing inside of my bag?

Is it nute lockout alone?

Whattttt isssss happpppeninggggggg???

Considering flushing both plants with peroxide?

Strain; Type, Bag seed, or NA- seedsman Sour Diesek Auto

Soil in pots, Hydroponic, or Coco?- double buffered and rinsed brick coco

System type?

PH of runoff or solution in reservoir? Plant 1- 5.1 plant two 5.8

What is strength of nutrient mix? EC, or TDS- FoxFarm dirty dozen 1/4 strength 800-1000 EC

Indoor or Outdoor- indoor

Light system, size? Spider farmer SE7000

Temps; Day, Night 74-81 for day. 64-70 for night

Humidity; Day, Night- 60% day 60% night

Ventilation system; Yes, No, Size- yes 4inch filter and intake

AC, Humidifier, De-humidifier,- yes ac infinity humidifier VPD set to 1.2

Co2; Yes, No- no

2

image
image770×1024 112 KB

3

Looks like potassium or mag deficiency?

1 Like
4

Thankyou for the reply and image!!
I thought literally the same. Dosing with double calmag to no affect. I’m feeling like something it causing lockout is causing what we see.

5

It’s nutrient deficiency caused by the plant flowering. When the plant flowers it sucks nutrients out of older leaves if there isn’t enough nutrients in the soil.

When you flushed the coconut coir you got rid of the nutrients and made the problem worse. You normally only flush before harvest or if there is nutrient lockout caused by too many mineral salts in the soil. This can occur if you don’t use enough water so some of the liquid comes out the bottom of the pot. You water your plants until 20% comes out and that will prevent mineral salts building up and causing nutrient lockout.

Plants use more potassium when flowering but still use some nitrogen and phosphorus, as well as trace elements like calcium, magnesium, iron, etc. Fertilize the plant every day for a week and see how it goes.

With coconut coir you should be fertilizing each time you water. If you get algae growing on the top of the medium you are watering too often and you could probably get away with watering once a day instead of 3 times a day.

You don’t need distilled or reverse osmosis water for plants. Just use tap water and add fertilizer. Stir it up and check the pH, you want that around 6.0-7.0, then water the plants. Most chemical fertilizers drop the pH of water so mix the fertilizer and water first, then test the pH of it. Coconut coir has a neutral pH (7.0) and doesn’t change the pH of the fertilizer water. So using fertilizer water with a slightly acidic pH (6.0-7.0) will allow the plant to take up the nutrients and use them.

Tap water might have calcium and magnesium in, along with chlorine and maybe other things and the plant can use those things too. People that use distilled or reverse osmosis water and coconut coir usually have to add calcium and magnesium to stop the deficiencies appearing. People that have hard water (containing lots of minerals) and use coconut coir quite often don’t have to add calcium and magnesium because there’s enough in the water.

I have never heard of root aphids. Aphids that affect plants generally feed on new growth (new leaves and stems).

The larvae of fungus gnats will feed on the roots of plants. Fungus gnats are small slender black flying insects that drive you up the wall when they get out of control.

Don’t worry about purple leaves. With plant genetics some produce purple leaves while flowering, others have green, one of my plants has black leaves during flowering. It’s normal and just related to the individual plant’s genetics.

6

It looks a bit like Manganese def. FF has a Bush Doctor Manganese.

Root aphids are a real thing but they don’t cause that kind of damage

1 Like
7

Gotcha, so might want to increase the K. See if that helps.