I have been growing a couple of years now, and every grow starts out the same with great bushy veg growth. I get beautiful large fan leaves with perfect color and shape. Then the flip, at first, it is great, sex starts showing, flowers begin to develop and grow fabulous; until I hit the wall.
About three weeks into flower, my girls begin to show signs of mag deficiency, even when my pH range is 5.9-6.2. The upper fan leaves begin to show brown spots, the tips turn completely brown around the edges, curl and die off; the sugar leaves soon follow suit leaving me with a bunch of ugly spotted flowers at harvest.
My current grow has been no exception. I added 1 tbs/gallon of cal mag at first sign of the mag deficiency which only worsened the condition and magnified the problem.
Here are my specs:
Strain: Cali Gold from ILGM
Medium: 90% happy frog potting soil with 10% additional perlite for better drainage.
5-gallon fabric pot
A/C Infinity Indoor tent setup: 36x36x72
Current pH reading: 5.9
light schedule: 18/6 veg, 12/12 flower
Nutrients used: complete Fox Farms line (Big Bloom, Grow Big, Tiger Bloom, Bembi, sledgehammer, kelp, mackerel, boomerang, microbe brew, etc…)
Scheduled per the FF soil medium feeding schedule: feed once a week and flush every three weeks.
I have researched and studied on this problem and really thought I had it whipped this time but nope, what the heck yall.
Post some pics. You’re in the scientific process at least. You’re detecting issues and tried to remedy it so that in theory eliminates that possibility. You know this community will get you straightened out.
@Lostgirl. Is this your arena?
Hi @SmittyJ, Based on your information, your soil pH is way too low in flower. 6.5-7 is where I understand it should be. I’m doing organic but the PH issue is the same. I had the same problem in flower the last couple of grows.
I did a slurry test only to find out my soil was in the 5.9-6.1 range. I started watering with a higher PH going in and that is helping. I also was low on the Cal/Mag and started adding it to mine in flower the last 3 weeks or so. It seemed to help.
You could also try cutting back on the feeding. When I used the Trio I found a feed-water-feed helped as well.
Share your runoff #'s as well and that will help shed some more light for those using salt based nutes in soil to weigh in on. @Lostgirl has it dialed.
The pH range for soil is 6.3 to 6.8.
Pics are always helpful in getting to the root of the problem.
Are you flushing per the FF schedule? If not, nute salt buildup will drop ph and cause lockout.
Too low. PH for soil is 6.2-6.8 starting low, ending high.
5.8-6.2 is acceptable for coco and hydroponics
Hey Grow Doc, yes Sir, I am flushing regularly as I learned that lesson a while back. Here are some photos. The first is from the first signs of trouble, the other five are today.
I should state that after I discovered that the cal/mag addition made the problem worse, I flushed immediately.
And last is a pic of my feeding and watering chart
Feeding is usually on Monday mornings at the about the same time each week. I water as needed but as you can tell I average every other day watering. I use tap water, but I check it every time and it is usually 7.0.
Considering I am in flower, is it safe to add pH up my water? If so, and I want to increase my pH reading, what pH range should my water be adjusted to?
Not saying watering is the culprit, but based on the chart, it appears and you stated 4-5 times a week. This is way too often IMO. So pH in the sweet spot range and cut back to 2-3 times a week and give her a flood, then the drought so the roots can breathe, rinse and repeat.
I grow in Happy and Ocean. When I am trying to get my pH up in the root zone, if my runoff is 5.9-6.1, I would go in with 6.9-7.2 the next time you give her a good watering. Make sure your ppm’s are 300-350 minimum so it holds the pH and affects the root zone.
pH up & down can be used anytime, whenever needed.
I would address the floor of your tent as well. Keep it clean Grobro!!
Thank you @Bonjoyle Shes still wet from the yesterday’s flush so I’ll give her a couple days to dry out a bit. Do I wait until my plants show a little thirst droop before watering?
I am certainly slacking in the floor cleaning arena yikes. Your setup is very well done.
Overwaterin is frequency not amount at one time. If you lean one way or the other, drier is better than wet, I use both thirst droop and the weight of my pot for my decision to water. It is never on a strict schedule. Sometimes she drinks more, sometimes less, also depends on stage, first 3 weeks of flower when the stretch is on and then when she starts stacking she will drink more and fertigation may increase but then during the last 3 weeks of ripening, she drinks alot less.
Dead plant matter and the runoff water evaporating and leaving that dirty film can definitely create an environment for mold.
Right on, I use the weight of the pot mostly, and I definitely see your point on the floor prep and maintenance concerns. That will be addressed today.
I would do 3 things, 2 @Bonjoyle already pointed out.
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Adjust pH properly
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Wait until bone dry to water/feed. This becomes confusing as “feeding” has a weekly schedule. Say you feed every Thursday. The bag may not be dry. Soil may be damp from previous watering potentially causing some issues. Cannabis, in soil with synthetics, needs a drench/drought feeding and watering routine. If you have to feed a day or so later than the schedule calls for, that’s totally ok
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Bump your feed up. In full flower you should be feeding roughly 1,000ppm with runoff within a couple hundred points. Especially if you are performing the Sledgehammer flushes
I would also like to see a slurry test both PH and TDS to determine salt levels in the medium. Appears to me like a combination of issues but nute burn is part of it.
What wattage lights? How far from canopy?
In fact; how about filling this out.
COPY/PASTE the below list into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so; Or post
NA (non applicable)
-What strain, Seed bank, or bag seed (photo or auto)
-Age of plant
-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
-Vessels: Type and capacity of container (fabric, plastic, etc)
-PH and TDS of Water, Solution, runoff (if Applicable)
-PPM/TDS or EC of nutrient solution if applicable
-Method used to measure PH and TDS
-Indoor or Outdoor if indoor, size of grow space
-Light system List brand and wattage/spectrum
-Actual wattage draw of lights
-Current Light Schedule
-Temps; Day, Night
-Humidity; Day, Night
-Ventilation system; Yes, No, Size
-AC, Humidifier, De-humidifier,
-Co2; Yes, No
If growing Hydro some additional questions:
-DWC? RDWC? Autopots? Ebb and Flow? Other?
-Distance of liquid below net pot (DWC)
-Temperature of reservoir
-TDS of nutrient solution
-Amount of air to solution
Always try to upload a clear picture in white light of any issues you may have to allow the community to assist you.
-What strain, Seed bank, or bag seed (photo or auto) California Gold, ILGM, Photo
-Age of plant from 12 weeks from first seed sprout
-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF SOIL-Happy Frog
-Vessels: Type and capacity of container (fabric, plastic, etc) 5 gal fabric
-PH and TDS of Water, Solution, runoff (if Applicable) 5.8/i dont know
-PPM/TDS or EC of nutrient solution if applicable
-Method used to measure PH and TDS soil tester
-Indoor or Outdoor if indoor, size of grow space indoor 36x36x72 A/C Inf tent
-Light system List brand and wattage/spectrum AC Infinity IONBOARD S33, LED Grow Light Board with Samsung LM301H Diodes
-Actual wattage draw of lights set on max
-Current Light Schedule 12/12
-Temps; Day, Night 84 at peak/73 at min
-Humidity; Day, Night 60/60 mostly, fluctuates with indoor A/C cycles
-Ventilation system; Yes, No, Size AC Inf 4"inline fan and duct
-AC, Humidifier, De-humidifier, House A/C unit, no special adjustments for tent
-Co2; Yes, No
Thank you, Grow Bros, I will clean up my space, change my watering habits, and increase pH I am sure that will need to be a slow process.
You won’t see the blemishes and discolored leaves really recover at all, but bud formation and newer growth should show improvement once lined up
Have you checked the accuracy of your meter? Most soil probe meters are problematic.