How to handle nitrogen toxicity in hot soil

[Loungeman420]

Hi All,

Day 17V
Pineapple Chunk

I've got a bit of a nitrogen toxicity problem that started when I left for the long weekend and decided to give my plant a bit more water than normal. For the record I'm growing in Miracle grow moisture control (a mistake) with 25% perlite and this particular instance was the first time I had watered till 20% run off so that the plant wouldn't dry out why I was gone. Prior to that I would only water about 2 cups everyday day or so to avoid releasing too many nutrients in the soil.

Before the weekend

After watering that weekend all of the following symptoms began to show and continued for the last few days. Yellowing/browning at the tips, curling/clawing, small amounts of brown spotting. Most of this occuring on lower/older fan leaves. The excess water has caused nute burn/nitogen toxicity to become present in the plant. I had measured the pH of some of the run off and it was around 5.5 pH, while the tap water going in was about 6.4.

Right after the weekend

Following Days

Today

I'm torn with how I should proceed here. Most sources state to flush the soil to remove the excess nitrogen, but I feel in this case due to my bad soil choice it will end in disaster by releasing more nutes, further burning the plant. Personally, I think I should keep waterings down to a minimum while the plant burns off the rest of the excess nitrogen and then continue the regimen that was working prior to the over waterings. New growth is still flourishing quite well, the plant has finally perked back up after about 3-4 days. It's beginning to look quite healthy, but I'll probably lose a number of the lower fan leaves. I'm considering transplanting it to better soil to avoid further issue, should I go ahead and do it?

Any advice on the situation is much appreciated.

 

[flexy123]

Sorry that I can't really help you there, but is your assumption that the thorough watering released more nutes from the soil?
(Otherwise I can't see why your watering would cause nute burn).

I don't think it as "optimal" when a good watering with runoff would result in something like this, then I would really consider changing the soil since a thorough watering (although less frequent) is actually something you should do. Who knows what this soil really does?

As for high amounts of perlite, I mixed some potting mixes (Canna Terra Pro etc.) with more perlite to make it 25%, TBH I am actually not really sure whether high amounts of perlite are good at all. This is just my theory, but I think from a certain percentage of perlite on, maybe 20% and more, the perlite and the fact it retains water and holds the soil most a lot actually has a negative effect. But this is just speculation on my side.

 

[Loungeman420]

Sorry that I can't really help you there, but is your assumption that the thorough watering released more nutes from the soil?

That's exactly right. Adding more water to the equation ends up releasing more nutes in the soil and is leading to the burn. I went back to my light but more frequent watering schedule and the plants new growth looks good due to the limited exposure to excessive nutrients.


I could probably make it work with this method, but its definitely sub optimal and I don't want to have to continue to stress over the unpredictability of the soil. I went ahead and pulled the trigger on some fox farms ocean forest soil. I'll do the transplant in the next few days and will try to remove as much soil as safely possible and then give it a good flush. Hopefully the stress doesn't hurt it too much, but it should work out better in the long run. Probably can start trimming off the bad patches too.

The perlite layer on top is mostly there just to reflect light, otherwise its about 25% throughout. From what I've read the main benefit of adding it to soil is mostly for drainage since it helps to prevent soil clumping.

 

[Fuzzy Duck]

I'm not sure what miracle grow use as ferts in the soil/compost blend ?

From what i've read it appears time release & these in general work on moisture / warmth of the medium used which can suddenly dump a lot of nutrients into the medium causing nutrient burn & nitrogen toxicity.

Slow release ferts are normally a little yellow/orange ball if i remember correctly & if ya got these in your growing medium i'm more likely on track, to which may last a few months if not more before being expended !


I might just check the label on the compost bag to see how long these nutrients are suppose to last tho.

 

[Dave Groomer]

I'm not sure what miracle grow use as ferts in the soil/compost blend ?

From what i've read it appears time release & these in general work on moisture / warmth of the medium used which can suddenly dump a lot of nutrients into the medium causing nutrient burn & nitrogen toxicity.

Slow release ferts are normally a little yellow/orange ball if i remember correctly & if ya got these in your growing medium i'm more likely on track, to which may last a few months if not more before being expended !


I might just check the label on the compost bag to see how long these nutrients are suppose to last tho.

I had a similar situation with another big store soil (was trying to stay away from MG) Only solution that worked for me, was transplanting into better soil. I got Fox Farms Ocean Forest and mix that with Promix bx and Perlite and my plants have been fine ever since. With non time released ferts you can flush the heck out of them. No with MG.