Yellowing leaves 1-2 weeks into flower

First time grow in a long time. Started from seed and I have no idea what strain as I pulled two seeds out of my father-in-laws stash to try and grow. Seedlings started in late May or early June in foxfarm happy frog and no nutrients were used. Transplanted to 3-gallon pot, happy frog soil with perlite and mushroom manure, and plants were topped twice. Transplanted again into 7-gallon smart pots, happy frog soil, FF grown big nutes used after 3 weeks along w/ big bloom. Once flowering started I was getting yellowing of the lower fan leaves which I assumed was N deficiency. After two waterings I fed again with 1 tsp of grow big with no improvement in yellowing. Flushed the soil and watered with tiger bloom thinking it was some other deficiency based on appearance. It’s been about two days and haven’t seen any improvement.

I just ordered a better PH meter, but the one I had was reading PH 6-7 for both water and nutrients. I haven’t measured the run off but will do tomorrow when my new meter arrives; Also ordered gadget to check PPM runnoff. Any help would be appreciated as I don’t want to mess things up so close to the end.

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Upper growth looks good. Lower may be yellowing from lack of light, maybe a touch of N deficiency. Some leaf die off is normal.
I’d up the N on the next feed. Then just follow the schedule.

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Welcome to ILGM @Drinkslinger has you covered.

Thanks for the help . Should I be doing full dose of the nutrients or only half? I didn’t know what week to use since I didn’t really start with the FF nutes until a few maybe three weeks ago. I only gave 1 tsp of the tiger bloom two days ago as I was afraid to cause burn. Some of the leaf tips looked a little brown on the tips already.

I recently have encountered this myself. So I will be following along. Welcome & thanks for the post.

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Yeah it was really weird. I didn’t use any extra nutrients until I transplanted into the 7 gallon smart pot. I started to yellow after only two weeks and that’s when I initially bought the FF nutes. Yellowing seemed to stop for about a week or so with regular water every 2-3 days depending on the weather. PA has been pretty hot/humid this year. I had to move the plant into my greenhouse bc it was getting to big on my deck and I was worried about my neighbors above me seeing my plant.

The second seed I planted ended up being a male. Looked completely different than this plant, was much more dark green and had a lot more foliage. Topped it not once and never fed with anything extra. Ended up burning it when I started to see the “balls”.

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pH 6-7 is a huge range. Were you using one of those cheap probe light/moisture/pH meters?

Runoff numbers will help us fine tune our advice.

If you weren’t using the full recommended amounts of grow big, I’d do so next feed. But ONLY if you can properly test the pH of the nute solution before using.

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Having some of the same I am in Pa also. increased the nuts today using Fox Farm trio have also been using cal mag. Started flowering about a week and a half ago. Some of the yellowing is normal at flowering. Upper leaves ok just lower yellowing. Don’t worry to much raise the n some and watch the plant it will tell you.

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I’ll keep you posted. New digital meter should be here tomorrow. I have one of those three in one meters but didn’t use it to measure my water/nutrient solution. I should be able to measure run off next time I water. In the mean time I’ll increase the N mat the next feeding and see what happens.

looks like N is low and its travelling up the plant, which is totally a normal thing for a N issue. And yep, if you are following a nutrient schedule then ph is an obvious starting point. Also, over watering sometimes contributes to the yellowing of leaves.
If this was a large outdoor plant, I would consider it totally normal for older leaves to yellow and drop off

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So I generally water about every three days depending on how heavy the plant feels and I also bought one of those 3 in 1 meters really to measure moisture (but I don’t trust it). I’ve been trying not to overwater and simply go by how Would you suggest feeding again with more N (grow big) even though I used tiger bloom on Sunday with my next watering?

With most synthetic fertilizers it’s imperative to measure the pH of your nute solution just before giving it to your plants. Fox farms nutes will easily drop the pH to 4-5.

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Yeah what @Drinkslinger said, ph is everything to a plant. If the ph is not in range, both in the solution and in the medium, the plant will not be able to eat what you intend for it. We call this lock out, looks like a deficiency, but its actually not. If we refer to a lack of N as a deficiency, the casual grower will instinctively add more N, when in fact there is a possibly a surplus of it already and now we have way too much! So job numba won is to correct the ph

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So then would it be better for me to water the plant after adjusting the PH and then measure the run off PH prior to adding in more nutes to see if it’s ph problems versus a deficiency?

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Yes. Runoff tds/ppm will give a look at how much “nutrients” the soil contains. The runoff pH will tell you If the soil is out of range for uptake of nutrients in the soil.

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This is the key. Need pH and PPM of runoff to know for sure what’s going on.

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So I got my new digital meters this afternoon. I used a gallon of tap water with an inital starting PH of 7.15 and PPM of 178. After watering and collecting the inital runoff: PH was 6.4, PPM was 438.

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Looks like your soil pH is low.
Also looks like your ppms are very low.

I’d feed full strength at an input of pH 7 this week. Collect runoff numbers again and re examine.

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I’m assuming too that I’m now waiting until I need to water again? Should I also assume that I’m in week 9 and do 2 tiger, 1 big bloom and 2 grow big? I didn’t really start using FF nutes until maybe 3 weeks ago, so I’m not really on a good schedule and don’t really know where to start now that I’m 1-2 weeks into flowering.

Yes, wait until they need water again, then feed. It’s probably just a couple days.
I’d put you at just about flowering. Day one of flower is when you see actual flowering, not when you flip the light schedule.

Use the week 4 schedule. Continue from there. Since your ppms are so low I’d skip this flush. Be sure to do the rest.

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