Leaf discoloration
- Thread starter Mrtree
- Start date
MickFoster
Well-Known Member
What is your feeding schedule?
Once a day
MickFoster
Well-Known Member
Are you feeding to substantial run off?
Do you ever use plain water?
I feed till %15 run off, I don’t ever feed plain water
Im embarrassed to say i do not know the EC of inflow or outflow. However, I have ordered a meter. The lights are 252w about 12 inch from plants
calvin.m16
Well-Known Member
No need to be embarassed some nutrients are fed by volume (grams/ml) and not by EC. What fertilizer are you using and at what rates? ml/gal etc?
I run MaxiGro/MaxiBloom by General Hydroponics and I can't remember the last time I touched a PPM meter or even a digital pH meter. I just use their dropper tester and make sure to not overfeed. 5 grams/gal in veg of maxigro and 7 grams of maxibloom per gallon in flower works perfect as long as I allow good runoff. If I didn't have a lot of runoff I'd cut back to 6 grams per gallon or even 5 depending how the plants looked.
You want to be checking your solutions pH before watering too.. Make sure your solution is 5.7-6.2 pH in coco.
Are you wasting the runoff somewhere or do the plants drink it back up? To me a guess would be a pH issue or even toxicity/lockout of some sort. To avoid this personally I give my plants a heavy pure water flush once every 7-10 days in flower. I always water until runoff then again after dryback (pots are almost dry but still moist), typically once a day if you size your pot correctly.
THink of it like ringing out a dish sponge, you rinse the soap out, squeeze it let it dry then give it fresh soap, except the sponge is your rootball and the soap is nutrients the plants can eat.
I've had people tell me never to flush during the plants growth/generative cycle but since I started doing that I literally never have a problem and I can be assured too much salts or certain elements aren't building up to toxic levels in the rootzone.
Last edited:
Right, but the amount of grams or ml's in their recipe are calculated by the manufacturer based its EC. This is why when using General Hydroponics 3-part, for example, growers have to cut the ml's down by 50-75% because the the EC is way too high for cannabis because tomatoes, cucumbers, eggplant etc., (what most of their customers grow) take 3.0-5.0 EC.
If you're feeding at the appropriate EC, you will never need to flush (seedling to harvest) and checking runoff EC will confirm that you're keeping the inflow EC at the proper level to ensure that you don't develop a salt build up.
Plants like consistency. When you're feeding it a certain EC, the plants have produced sugars to deal with the salinity of the feed they've come to expect, and when you drench it with plain water, it has to use growth energy to quickly convert those sugars to starches to prevent it from taking in too much water. Then when you go back to feeding a high EC, it has to expend energy on quickly producing sugars again to process the salinity of the water. Osmotic stress is placed on the plant with flushes.
If that's not being dimmed, then that is likely the culprit. 12" at 252W LED is way too high PPFD in veg. You want to be around 280-550 in veg. Did you recently lower the height or increase the wattage of the lights?
But yes, use an EC meter to monitor what feed is going in and what comes out can give you clues as to what the problem isn't when a problem arises. After a couple of grows, you'll know what amount of ml per gal is consistent and won't need to measure inflow or outflow but maybe just periodically just to make sure everything is okay.
calvin.m16
Well-Known Member
I'm in large pots right now, there's plenty of nutrient still in the coco when I give plain water. I'm only shooting for 30% runoff with the plain water feed once weekly. I use a calibrated BlueLab Pulse meter to stab the coco and its still well over 2.0 EC a few hours after giving plain water in 10 gals. My EC after a normal feed are in the 2.5-2.6 ballpark. If I were in smaller pots (soon again I will, needed less waterings for travel) I would feed them like usual, then flush with water, then feed again within the same day.
Even if you feed the correct amount of nutrients, and allow 20% runoff, you can still accumulate salts/elements in the coco that could cause a toxicity issue. I would rather flush and be sure than hope all is well cause I've been bombing them with the same fertilizer solution.
I don't think periodic flushes of plain water are going to do any harm to the plants. I've done without, and with, my numbers are the same on my charts for yields.
I'm also not saying everyone should flush their plants once a week, but it's worth considering. Even every 20 days might be smart.
You do have a point though, I quit using compost teas due to the addition of sugars, I didn't want the plants to get lazy or something due to having lots of extra sugar in the rootzone. I also was scared to throw off the lucas formula by adding in organic stuff. I have had similar success with just salts and water as I have with salts + compost teas/microbes/mycos + water.
This run I'm also keeping my day/night temps and humidity very steady (1.4 vpd) in flower to see what happens, where before I would let temps drop at night as low as 65 F.
DanKiller
Well-Known Member
When you actually look at your plants and put the charts aside, you can tune your waterings in accordance with feeding each time, less or more, always in small changes, always consistent.
People think that if they gave 0.8 ec for instance, it should only go up from there, no... like @calvin.m16 said, salts will build up even at low doses and even when you allow runoff.
The best solution is to adjust everything beforehand to optimal conditions instead of chasing your own tail later on.
Roots don't like flactuations, flushing should take place only if you screwed things up beyond normal repair and as last resort.
The main problem is people get carried away, either in too much or too little without actually looking at the plants and understanding what is needed.
I always follow the plant, starting at my water starting point (usually 0.5 ec) and increase very slowly according to what the plants show me.
If I see over feeding, I know it's small above what was good, and I start to take it down also slowly until I reach again to a good condition.
Coco is subject to problems with salts, as most people just grow in dense grained coco which holds tight salts and even when giving less ec water, it still has a hard time getting rid of past salts in it..
A lot of factors going into play here,
That's why I always use ewc with my coco and adding salts very slowly after 1 month of growing.
People think that if they gave 0.8 ec for instance, it should only go up from there, no... like @calvin.m16 said, salts will build up even at low doses and even when you allow runoff.
The best solution is to adjust everything beforehand to optimal conditions instead of chasing your own tail later on.
Roots don't like flactuations, flushing should take place only if you screwed things up beyond normal repair and as last resort.
The main problem is people get carried away, either in too much or too little without actually looking at the plants and understanding what is needed.
I always follow the plant, starting at my water starting point (usually 0.5 ec) and increase very slowly according to what the plants show me.
If I see over feeding, I know it's small above what was good, and I start to take it down also slowly until I reach again to a good condition.
Coco is subject to problems with salts, as most people just grow in dense grained coco which holds tight salts and even when giving less ec water, it still has a hard time getting rid of past salts in it..
A lot of factors going into play here,
That's why I always use ewc with my coco and adding salts very slowly after 1 month of growing.
LedbetterCookiez
Member
Trace nutrient deficiency. Very common problem. You see it tons, always called something else. . Maybe in a few months my boss will let me tell nute lol.
If you're doing feed/water/feed, especially in the same day, you're feeding too high of EC. If you think about how DWC is, how the roots are constantly submerged in nutrient solution, the goal is to attempt to keep the EC the same 24/7 and only increase as the plant matures.
If you're at the correct EC, allow for 20% runoff, then the only way you will accumulate a salt build up is if you did dry backs.
How sea salt is made is by collecting seawater water in shallow pools and letting the water dry out and all that's left over after evaporation are salt crystals.
In coco that's allowed to dry back, the same thing happens - the medium dries out and the salt in the nutrient solution crystalizes out of solution and when you feed the next time to 10-20% runoff, the salt crystals raise the EC of the current feed causing the rootzone EC to spike. As this keeps being done the EC continually gets higher and higher and a flush is necessary.
However, if the plants are never allowed to dry back more than 10% and the EC is appropriate, then the salt never has a chance to crystalize and build up in the medium because you're constantly providing a stream of new nutrients at the same EC that replenishes the "old" nutrient solution in the medium hours later and maintains a consistent rootzone EC.
When I'm in full flower and feeding at like 1.3EC several times a day, my runoff EC is in the same range all the way to harvest.
I didn't say it would harm them; like humans, plants learn to deal with stress. An employee that is continually under stress, having to place time and energy toward tasks that are not directly related to their job of producing results for the company may still be able to produce well, but he or she would be happier if the entities responsible for creating job stress that isn't directly related to their assignments wasn't there and would probably perform better.
You grow good plants and give good growing advice on the forums, so all I'm saying is that this specific feeding protocol in coco is dated. Feeding at a high EC and then flushing every 3-4 weeks is not the optimal way of growing in coco because unlike in soil, you're feeding the roots directly. For all intents and purposes, the coco is just there to prevent the plant from falling over and it's a hydroponic method of growing.
calvin.m16
Well-Known Member
Following the plants is my method as well. Using such a simple feed of just maxibloom I can very easily bump feed up until I see a tiny bit of tip burn then I back off until it stops. That seems to be the goldilocks zone.
calvin.m16
Well-Known Member
I practice drybacks is part of why I do a plain water flush periodically. I know it's not ideal, but a day of slightly lower EC isn't hurting my plants at all.
You can see I did get some tip burn on this plant as I'm working with all new genetics. I was able to quickly notice it and cut my fertilizer back a small percent and it stopped progressing.
With 12 big mama plants going its kinda hard to keep things dialed when you have the same flower reservoir and 4 different genetics but I have figured out the magic # for maxibloom is 6-7 grams per gallon depending how plants look. I tend to run higher temps (80-82 F) and vpd (1.4 vpd) so I try to keep the feed more in the 6g/gal range because I know they are taking more nutrients up than a cooler room with lower vpd.
I didn't start seeing epic daily growth until i began practicing drybacks per Athena Ags chart.
Day 40 of flower, Bimburn - Cereal Milk, Brothers Grimm- Grimm Glue, Ethos - Purple Sunset and Pink Runtz. I am not digging the pink runtz at all, super stretchy and small buds. Seems to be how every runtz plant I grow does. The under lighting is still there because I had a power outage and was using it to keep plants from being in darkness for more than a few days.
Here is last grows run with the same feeding/watering strategy *note the white salt at the bottom of the pots*
