Emilya Green and several others have mentioned in the past that tip burn like that is a sign that the fertilizer program is pretty much spot on. Since the schedule from Fox Farm says to fertilize "up to twice a week" so one feeding in a week is OK. Nothing stopping you from doing 1 dose this week and going back to doing 2 next week.
Thanks SmokingWings, it's good to know I'm not overfeeding. I took your advice and did a flush 3 days ago. I fertilized immediately after the flush. The soil was saturated with water, so I couldn't add as much of the fertilized water as I wanted to without the saucers overflowing with runoff, but I saved the rest of the fertilized water and fed them again the next day. They seem to be doing well! They're definitely filling out quickly! Attached are some updated pics from yesterday.
You're way overfeeding your plants and Fox Farm tiger bloom is way to low in nitrogen for running plants in flower in containers. Not enough Ca/Mg and not a complete plant food.Long time toker, first time grower. My state just legalized home growing in August 2023, so I took full advantage! Unfortunately, I’m a newbie, so I am having some issues and could really use some expert opinions on what is going on.
The pictures I have posted are very recent. I switched to 12/12 lighting 4-1/2 weeks ago. I’ve given as much information as I can, but if you just want to get to the issues and questions, that is bolded at the end of this post.
Strain: Fatso OG (started with rooted clones)
Setup:
Gavita Pro 1700e LED
Gavita UVR LED (UV-A supplemental light) (x3)
3-gallon black fabric grow pots (x4)
Vegetronix Moisture Sensors
Medium: Fox Farm Ocean Forest
Water: Reverse Osmosis remineralized with Organic Cal-Mag by TPS Nutrients (my tap water is awful, so this is necessary)
Vegetative Fertilizer used after ~1 month in the Ocean Forest: Fox Farm Grow Big
Flower Fertilizer used: Fox Farm Tiger Bloom
pH Meter: PINPOINT by American Marine Inc. calibrated before each use with Biopharm reference solutions
pH adjustments with pure, food-grade sodium bicarbonate and citric acid
TDS Meter: Extech EC400 ExStik calibrated before each used with Biopharm conductivity standards
Lasko 16”, 3-speed oscillating fans (x2)
Sealed grow room
Hygrostat controlling dehumidifier and humidifier
Thermostat controlling air conditioner and oil heater
CO2 meter and dosing system
Mylar reflective coverings on all walls
Books I’ve been referencing:
The Cannabis Grow Bible, 3rd Edition
7 Steps to Grow Cannabis
Growing techniques:
-I started the clones in 1-gallon fabric pots and transplanted them once they approximately doubled in size
-Mainlining: Once the clones grew out to 6 nodes, I topped them to the 3rd node and removed the 1st and 2nd nodes. Then, once the two remaining branches grew out to 4 nodes, I topped each down to the 3rd node and removed the 2nd node. I kept lightly training them with plant ties to attempt to get all 8 shoots to a similar height.
-The day I switched to 12/12, I pruned all growth on the bottom third of the plants.
-I maintain CO2 levels at approximately 1400 ppm throughout the entire grow.
-When the plants were young, I kept the light 36” from the canopy. Once they were well established in the veg stage, I kept the light 24” from the canopy and have maintained that since.
-I used a lux meter and followed this guide for light intensities for the different stages (I’m currently at 100% light setting on the Gavita controller): Choosing LED VS HPS Lights - 4trees Cannabis Building
-I started the supplemental UVA lights once the plants were well into the vegetative stage
-I water every 2-3 days after the soil has mostly dried out but just before the plants start wilting. I overfed early on, but now I am being much more conservative and only feed every other watering.
What I know I’ve done wrong and have been trying to correct:
Recent Feedwater/Runoff numbers:
- When I started, I had a cheap TDS meter from Amazon that was giving me bad readings. This led me to add way too much cal-mag to the water (this became obvious when I purchased the Extech TDS meter and calibrated it) for much of the vegetative stage.
- I also mistook the early signs of nutrient burn as what I thought were nutrient deficiencies, so I kept adding more fertilizer and overfeeding through much of the vegetative stage. Once it finally became obvious that what I was seeing was actually burn, I started cutting way back on nutes.
Date Water pH Water TDS (ppm) Runoff pH Runoff TDS (ppm) 9/14/2023 5.78 1147 6.25 2025 9/17/2023 5.97 189 6.7 1147 9/21/2023 5.92 908 6.54 1850 9/24/2023 5.91 272 6.94 1191 9/26/2023 5.87 269 7.02 1197 9/29/2023 5.73 1077 6.57 2075 10/2/2023 5.83 1288 6.53 1768
Concerns:
-Leaf discoloring: my biggest concern is the discoloration that is continuing to get worse. It started as purpling on leaves closer to the top of the canopy (not all leaves). The purpling started at the edges of the leaves and moved its way in. Now, as it’s getting worse, some of the leaves are turning red. My searches online and through my books don’t seem to give a good answer for purpling at the edges of the leaves, so I’m pretty confused.
-Runoff ppm: My runoff ppm lately is coming out higher than the water I’m adding to them. From what I can tell from my research, there may be a buildup of salt in the soil, which would make sense, since I know I was adding too much cal-mag early on.
Questions:
-What is this discoloring telling you? I’m new to this, and I’m worried I’m still either overfeeding or underfeeding. I’m just not sure which. Or could it be from salt buildup in the soil?
-Should I flush the soil with pure water to remove salts, or will that disturb the plants since they are so far into flowering (but obviously not done—I believe they need 3-4 more weeks from what I’ve read)? Or should I just let them ride it out at this point and only flush at the end, right before harvest?
-Should I trim “problem” leaves? During the veg stage, I would trim off any leaves that were heavily discolored so the plant could focus energy on new, healthy growth, but do you all do that in the flowering stage too? Or do you just leave them until harvest, regardless of discoloring?
-For the next grow, should I plant in 5-gallon pots instead of the 3-gallon pots this time?
He's dialing in nutrient strength by tds/ppm measure so why would he look at the back of the bottles? The main problem is he's feeding the plant to much food in a sub par mineral ratio causing lockouts and nute burns.
Thanks for posting, Wastei. I appreciate your different perspectives on this. I'll be interested to hear what the others say about your responses.
Thank you for the tip! I took pics of the calyx's last night. I'm posting them below.
Nothing to get nervous about.
