Nitrogen deficiency or nitrogen surplus?


Hey all,
Growing five plants of various strains (already harvested three auto-flower, with nice results). Four of these are in five gallon containers, and one is in the ground. All are in a greenhouse, and I am running a dehumidifier (see my previous thread on bud rot) and an automatic fan set to come on at about 85F.

The plant in the ground is amazing–the stalk is nearing 2" thick, and it’s literally growing out the greenhouse roof. The four in the five gallon buckets are nice and tall, 1" thick, and fairly full, but not as healthy as the one in the ground.

I apologize that I don’t have photos, but the one in the ground is nice dark green, really bushy, and doing great. The ones in the buckets are more pale green, and over the past 3-4 weeks, they have been yellowing from the bottom up. The leaves get pale, then yellow (sometimes with brown spots), then die and fall off.

For fertilizer, I started with ILGM stuff, and now that I ran out I use a balanced organic fertilizer, general garden stuff (Dr. Earth). I also have a bloom fertilizer, (low N, higher P, K), but not using it yet.

When I suspected water was the problem (because buckets get very dry quickly), I moved the buckets into a large watering trough, so that when I water, they drain out the holes in the bottom and sides and stand in water for a day or two and stay moist longer. I do have to water every 3-4 days.

I just reapplied fertilizer again a few days ago, and it’s too soon to tell if this was the cause. Last fertilizer was probably 5-7 weeks ago, applied on the surface of the dirt and watered in (it’s pellet, so breaks down slowly each watering).

I am really torn on this one. My instinct is that it’s a N deficiency, but wonder if it could be that the fertilizer is too hot instead? Should I take any steps to remedy this, other than just fertilizing and watering?

Thanks for any help, and talk soon.


Whitout any pictures wee can’t say what is the problem… Maybe this charts will help you to identify the problem. thenug-WItBVPhsFaNutrient_Chart2


@Bmacpiper how old are your plants?
Looking at your mold thread it sounded like you are well into fowering.
If so it is natural for lower leafs to yellow and fall off during the later stages of flowering.
If they are in fact a ways into fowering you will want to limit the amount of nitrogen they receive. They will need more phosphorus and potassium during fowering and less nitrogen.
If the plant that is in the ground is extremely dark green it could be nitrogen toxicity but it is tough to say for sure without pics.


Thanks Jmesser80. The bud rot thread was on my auto flower plants; the ones I’m discussing here are just barely showing a few pistils, i.e. not really into flowering yet. I did see the yellowing you mentioned on the auto flowers.
Will try to get some photos up; anyone have a good free hosting site for photos that allows forum posting? Google pics doesn’t work with several forums I frequent; haven’t tried them here. Photobucket just became very much “not free”. :slight_smile:


M4ur–thanks for the chart, I’ll have a look and see what I can find.


You can upload your photos directly to this site. No hosting site needed.


Just a follow up, a number of weeks later. The plants in question were in 5-gallon buckets, and continued to yellow from bottom up. Ultimately they were just badly root-bound. The buds are of course pretty small, but not terrible. I had to go ahead and harvest a little early because I was worried that the plants would die and ruin what bud there was. I’ve decided that 5-gallon buckets are just too small, especially for a greenhouse plant–so next time will use the actual soil bed I have instead. Perhaps a plant could be kept pruned back to keep the plant small enough for 5-gal of roots to support. I still have one plant in soil and it’s looking lovely; frosting up and going crazy. Like Dr. Seuss. Best, bmc


Yup, a picture 2 months ago would have solved it in a second.


No doubt. Only just figured out how today. :slight_smile: Here’s one of the roots, pretty impressive:


You’re lucky they didn’t hermi on you!


Great, something else to worry about! :slight_smile:


Wow, those are some dense roots!

I’m in 10gal soft pots. I hope that’s large enough because I wasn’t planning on transplanting to larger pots.


Well, a year later and thought I’d ask again about this year’s crop. Interesting thing–I started 8 plants at the same time and all have had identical conditions. They are now all in the greenhouse; I amended the bed with organic pellet fertilizer and added fish compost. One plant is yellow, the rest are all doing great! Funny thing is, the yellow plant (which is super silver haze) has had mini-buds on it since it was tiny, like maybe 3" tall. It’s like a pot bonsai tree…
Any ideas welcome, and thanks. My gut is that the soil dried a bit while I was away and so the plant couldn’t take up fertilizer. But hmmm?

The plant in question is the bottom left in the overall view.