I’ve had a problem with thrips for about 4 weeks now. My crop is organic and was outdoors, now it’s indoors. About two weeks ago I put diatomaceous earth on top of the substrate, and I was only watering in the middle so as not to wet the diatomaceous earth. One day I watered everything and added more diatomaceous earth, and 5 days ago I threw diatomaceous earth on the leaves, and of the 21 plants, 5 were like in the photo. They started to turn yellow and wilt, with black spots where they were turning yellow, then they dried out and curled upwards. I cut some of the leaves in half, but they continued to wilt. I washed the leaves to remove all the diatomaceous earth, but I didn’t notice that it had remained on the underside of the leaves. I went and washed them again yesterday. I’ve been researching and diatomaceous earth dries out the leaves, especially since the plants are starting their 5th week of flowering and have a dehumidifier. Another thing I researched is that diatomaceous earth raises the pH, so I did a runoff and the plants had an average pH of 7.0. In some pots, the runoff water even came out white from so much diatomaceous earth. So I watered the other plants with just water and pH 5.0 and even so the runoff came out around 6.6.
Could the plants have gotten like this because the pH went up because of the diatomaceous earth?
Me personally have never seen dio react like that to my plants.
I add some to my medium mix for the bit of silica you get from it.
Some bug reduction.
When I top dress with it, I will bottom water the plants for a week or 2, filling the saucers.
More to keep it dry as you also said.
There are different sizes of Dio, if that is the correct term.
Like some is for pool filters, that I think is larger size of particles.
After I bought some pool quality, many years ago, my mentors, told to use a consumable form, I get mine for our local health food store.
I never knew we can drink some forms of it for gut cleansing, BUT NOT the pool quality Dio.
I’ve never read Dio will lock out nutrients, but it sure looks like lock out in your leaves, well something is anyway.
I also use diomas to top dress my soil, I water from the bottom also - always! but as @webeblzr noted, it should be ‘food grade’ diomas earth only - from all that I have found and read on the web.
regards,
The diatomaceous earth I used is for growing cannabis, I bought it at an organic cannabis products store, I did a test here, I put 1/2 liter of water and added a little diatomaceous earth, the pH went from 6.5 to 6.9, I put in the pot and on the leaves about 30 times more than I tested in the water, it could only have been that which made the pH of the soil go up and leave the leaves like that, I didn’t do anything different from what I was doing in the last few weeks
My cultivation is organic, and in the runoff, in addition to the pH being on average 7.0, the ppm varied from 200 to 300, as I have 21 plants and had little space, I did it in 7 liter pots (1.84 gallons?). Since this pH problem occurred, I’m thinking about doing a flush with a low pH, until it adjusts, and starting to use mineral fertilizer, to be able to fatten the buds, they are too thin to be in the 5th week of flowering.
I dont have a lot of help to offer but i have absolutely covered the top layer in de on my plants and watered it in like a flood with zero issues. Typically when i get issues like you have its something ive done. Soil isnt healthy for whatever reason. Maybe try a worm tea next watering to encourage good microbes.
Upon re reading your post, are you watering the tar out of them? You may just be over watering at this point. A lot of in door plants dont need that much water. Some in flower barely need any. I do a lot of stuff that people wouldnt agree with but my plants come out great. Id try to adjust your watering now but still give them the compost tea. Dont worry about nutrients either. Just make a healthy microbe tea and dont over water them.
I was just wondering, not saying this is your issue. but what are giving them for calcium?
I had similar issues last year, and started to buffer my coco coir (the blocks) after rinsing them pretty well.
Same with the coco husks I use, I buffer that also now after hydrating and rinsing it well.
Adding some gypsum to the water tote, has helped me out a lot.
I’m not watering too much, in fact I’m waiting for the substrate to dry out well before I can water it again, because if the soil is left too wet, more thrips will appear.
I am using bomb fruit, ocean mix, bokashi, lmx, em5 fertilizers