I have six plants of different strains growing outdoors in LA in the standard no-till soil mix. Started them from seed about 8 weeks ago.They were perfectly healthy and growing very well until about a week ago, when I noticed problems with the lowest leaves. It doesn't look like they're just naturally dying off. Some of the leaves are fading from a rich, healthy green to a sickly, splotchy light green, while some are turning yellow fast with brown spots, and some are even shriveling up and turning crispy brown. I spray the plants with neem oil every week and just top dressed all of them with neem seed meal about 2 weeks ago. There are some aphids and thrips. The latter haven't been a problem, but I'm very concerned about the aphids, because my previous crop a few months ago was devastated by an aphid infestation I didn't catch until it was too late. The leaf damage looked just like this. One of the pictures shows perfectly healthy new growth at the top of my OG Kush plant. 5 of the 6 are like this, but the White Widow x Big Bud has lighter green leaf tips on the top growth, which you can see in one of the photos. Not sure what's causing this. That plant seems to be the least healthy one, and today the whole plant is starting to wilt slightly. Even after watering (it's been really hot here recently), the plant doesn't have the vigor it did a couple weeks ago. I just picked up some ladybugs, which I'll release at dusk tonight. Hopefully they'll take care of the aphids. But I'm worried the plants might have a virus or some other problem I'm not familiar with. Would appreciate any feedback! Thanks.
No, I'm growing in organic soil. The plants were growing completely healthily until just recently, so I highly doubt it's a pH issue.
you might want to check it dude. I had the same type of issue and it was because of PH. I ended up having to PH down my water quite a bit to make sure the plants were able to absorb everything properly. Thats always the first step when trying to diagnose your plants is to make sure the PH is properly balanced. Make sure you check your water PH, and then check your runoff PH. Should give you an idea of whats happening in that soil.
You can still have pH problems in a organic mix, like if it wasn't limed when the mix was built and the soil not correctly buffered. Be that as it may, I agree with the doubting that it's a pH problem. pH problems usually develop over time, not all at once, so to speak. *I* would look more at the last thing you did, especially 2 or 3 weeks in the past. Like, just how heavy was that neem cake top dress? Second would be the aphids. They can do a lot of damage in short order. I've had the best results with Safers soap. This includes "before" when I was still using pesticides Ladybugs are good to have around, mainly for prevention/control, but way too slow when there is a big infestation. They can only eat so many per day.
My mix has 1 cup of lime per cf, so I think the pH should be about right. The top dress wasn't that heavy, I just scattered it around, didn't get overzealous. I just released a ton of ladybugs on the plants last night. Unfortunately it looks as though 90% of them were dead--went out this morning and saw a ton that never woke up, and only a few crawling around. I think a lot of the living ones must have flown away--is that possibly a good sign, indicating there aren't many bugs for them to eat? Spent about 10 minutes examining the plants and didn't notice any aphids. Plants look pretty vigorous today, so I'll monitor over the next few days and see if the problem keeps progressing.
My guess. What kind of lime? Dolomite? If so it has a tendency noto to break down weird overy time. Like to much magnesium and not enough calcium. I'm guessing this a new batch of soil? First run. And if so your minerals may not be available yet. Do you have any oyster she'll in your mix? CA and mg def seem to go hand in hand and it looks like a bit of those two to me. But that being said there is really not much to do but maybe really boost your micro herd with a simple ewc tea. And top dress with good compost. I've had issues with first run in no till soil beds and in the end it works itself out. As long as pests are ruled out. Also are you filtering your water?
Yeah, dolomite lime. This is the second run with this soil. No oyster shell, but there is crab meal, if that's relevant. But I've read a lot of posts on this forum about getting great results with mixes that have neither of those, or dolomite lime. And it's weird that the problem would suddenly appear, from the bottom up, no? Not filtering my water, just using straight LA city tap water.
When the organic soil mixes commonly shared in this forum aren't performing as expected, I tend to suspect that the water used for irrigation is the problem. The pH of your irrigation water DOES matter, especially when growing in 10 (?) gallon no-till pots and on the second run. Overall length of grow time compounds the problem (outdoors, that's a lot), as well as your own watering methodology. If you have water that has a "high" pH, the aforementioned factors will indeed create a pH problem, regardless of the fact that your soil mix is "organic". And you have liming agents in your mix... Have you ever had problems with your previous grows utilizing the same water source? Can you post some better pic's? All full plant pic's?
Thanks for the input waktoo. They're 20 gallon pots. Ugh, just looked at the water quality report for 2016, and it looks like the water in my area has an average pH of a little above 8. Good thing you helped me catch this, as I'm about to mix up a ton of soil for a bed I just prepared. What would you recommend I do? The soil is one third peat moss, and there's a cup of lime per cf. I'll take more photos tomorrow morning. Thanks for the help! Edit: And yes, my first crop in this soil had the same problem, and it progressed to become much worse. But it also had a massive aphid infestation that I didn't catch because I was laid up with a broken ankle. I was originally vegging those plants inside. I put them outside to flower at the beginning of January. The plants were growing very well, and then the problem began around the end of February.
Take a gander BrassNwood's replys in the Pure sulfur/gypsum thread I just bumped up and how he deals with LA tap water He and Wak both have to deal with high pH water loaded with carbonates and both are extremely well versed in this area.
I'd try a calcium magnesium suppliment. Especially being on city water. I know it's hard to open a bottle but general organics camg plus is not a bad product. Maybe top dress with kelp and ewc maybe some oyster she'll. I'm betting your dolomite is breaking down in the wrong ratio. Typically plants want double the calcium to magnesium and I think dolomite will supply to much mg which can lockout ca.
New photos attached, showing all six plants in full and some closeups of leaves. IMG_6626 shows some weird light green/yellow coloration on some of the sour diesel's leaves. I don't see this on any of the others. The problem seems to be slowly progressing up the nodes. Here's the water report: http://www.mwdh2o.com/PDF_About_Your_Water/2.3.1_Annual_Water_Quality_Report.pdf See the table on page 10 (of the PDF). A report from a few years ago said the treatment plants for my region (Eastern LA) are Weymouth, Diemer, and Jensen. But in any case all the plants show an average pH of above 8. I should note I have about 1 cup of gypsum per cf in the soil, for what that's worth. Is it true that peat doesn't actually contribute to long-term soil acidity, and that the acidity effect is really only seen early on?
I strongly suggest that one or more of the mobile elements is in short supply and translocation is occurring leaving older leaves with chlorosis. I also suggest taking a long study of each of the primary and secondary macronutrients. Those outdoor plants are going to grow to the limits placed on them of that suite (n, p, k, ca, mg, and s). pH might affect these elements as well. Managing pH is a real challenge and the only real solution IME is copius amounts of quality soil organic matter (finished quality made compost, quality EWC) wjth the emphasis being on "quality". Citric acid easily found in the canning section of the grocery is a wonderful organic tool for lowering pH. Since your water is loaded with carbonates the amount of citric acid required to hold the pH against such a strong base buffer (carbonates) may require multiple pH tests to determine the sweet spot where the base (carbonates) are effectively neutralized by the acid. IOW, one might add 1/4 tsp of citic acid to one gallon H2O, immediately test the result getting a favorable reading but test again 30 mins later to see the pH has risen again. If true it would indicate high alkalinity which requires more acid to increase acidity. IDK...just a couple of thoughts.
The humus portion of my soil (1/3) is mostly Bu's Blend compost, with some Worm Gold Plus as well. I didn't do a compost or EWC top dress before this cycle, so maybe I should do that? I also need to pick up some straw this week to lay down. I'll look into citric acid...guess I should pick up a pH test kit too. Man, I was under the impression from my general reading here that pH wasn't an issue with organic growing. I got the lime idea from the Easy Organic Mix thread. Seems like the current thinking is that adding lime is generally a bad idea, so shouldn't that post be updated accordingly?
@waktoo - what did you mean by this "Overall length of grow time compounds the problem (outdoors, that's a lot)"? Why does outdoor vs indoor make a difference here, and did you mean that the problem gets worse over time because of how the soil changes, or because the plants reach a point in their growth where they experience lockout?
Your pH is one thing, and can be easily neutralized with organic inputs like citric acid. But the levels of dissolved sodium in your water give me concern. I've never seen municipal water reports with levels that high. Municipal water systems generally try to filter it down to <20 ppm for folks that have issue with high blood pressure. Your levels from Weymouth and Diemer are higher than the levels present in my own well water (100 ppm). Sodium Absorption Ratio is something that I do not fully understand as of yet. But I do know that it is an important factor when considering how it affects overall soil chemistry. In my estimation, you're beginning to experience sodium toxicity. I didn't see any Blumat set up for watering, so I'm assuming that you're top watering like most folks do. How quickly/slowly does your soil absorb water? Does it tend to "pool" on top for a little bit before being absorbed? This Wiki' page describes SAR a bit, but consider that it references use of irrigation water for growing crops IN THE GROUND. Sodium build up in this instance is not as profound as it may become growing in pots, as ground soils are subject to leaching. If you water your pots like most folks, there is little to no run-off, and therefore no leaching of excess sodium from the "soil column". With your water, what this means (especially when considering no-till cultivation) is that soluble sodium levels in your soil will continue to build up over time until they reach toxic levels and the plant really has no choice but to take them up due to their comparatively high concentrations. These high sodium levels will also affect the plants ability to adsorb the nutrient ions that it really needs for healthy growth, especially Ca & Mg. I really think that you're just beginning to see the "tip of the iceberg" as far as problems are concerned... Sodium adsorption ratio - Wikipedia Here's a PDF that I found helpful in determining that my well water was responsible for all the troubles I was having with my organic soil mixes. I had REALLY serious issues that were most difficult to diagnose because there was no continuity in the problems that I was experiencing. It certainly didn't help my situation when I used this water to hydrate the compost/vermicompost I was building for my soil mixes. The carbonate content of your well water is just like adding "liquid lime" to your soil every time you water. What sucks about this (other than driving your pH up and affecting nutrient availability) is that it reacts readily with free hydrogen in the soil solution, so that the "solid" liming agents (crab shell meal, dolomite lime) have very little opportunity to react with the free hydrogen in the soil, which also releases the Ca/Mg that they contain. Make sure to read the part about SAR. "Sodium toxicity, whether due to root adsorption or foliar absorption of Na, is expressed as marginal leaf burn on older foliage." I think you're going to have to invest in an RO system...
Ugh...I would really like to avoid dropping hundreds on an RO system if possible... How could LA have such high sodium levels in their water? Everyone's watering their gardens with this stuff. The water absorbs pretty well in these 20 gallon pots, though if I pour a lot on quickly in one area, there will be some pooling. In some smaller pots with flowers that have the same soil, the water pools much more. It's interesting that the problem with this crop appeared after about the same amount of time outdoors as the previous crop--about 7 weeks in. Are the plants experiencing nutrient lockout because they've reached a certain size? Maybe the plants in the previous crop became a target for aphids due to their declining health from the pH or sodium issues. I'm still barely seeing any aphids, btw. Looked a bit this morning, didn't see any. Did you end up getting an RO system yourself? Did the problem stop after that?
You have to remember that some plants actually require sodium, and some plants aren't as affected by high sodium levels as others. And sodium leaches from ground soils. I really am surprised that the levels are that high coming from a municipal system... Yes, I have an RO system that I use as backup when collected rainfall/snowmelt is insufficient for my indoor watering needs. And yes, the problems went away after I stopped using my well water. And planted in soil that wasn't built with the well water. We even stopped using the well water on our house plants (my lady has a lot!). Their health improved measurably as well. Did you ever grow at the house you're currently in prior to trying no-till?