Leaf issues and general question

[Ganggreen99]

I have a 5x3 tent with three plants that are mainlined in 7gal Fox farm soil. My lights are sf4000 and sf2000. I'm in week 7 of veg but in week 6, I started seeing these issues on a few leaves (see pictures). I PH my water at 6.8 or 6.9 does anyone know what these issues could be? I use Fox farm nutrient line but I'm thinking of switching to advanced nutrient so that I don't have to Ph anymore. Should I flush before switching or not even bother? Lastly I'm thinking of throwing 2 additional 3gal pots in And vegging for another month. Will I have space? Thank you

 

[Delps8]

The issue can be nutrient availability or it could be nutrient uptake. My money is on the latter.

If your nute mix is incorrect or if your soil is "defective" (if there is such a thing - I grow in hydro so mea culpa), the issue could be availability.

Nutrient uptake is driven, to a larger degree by, temperature and humidity and, to a lesser degree, wind speed. What's the weather like in there? Also, what has changed in the past few weeks, perhaps one or two weeks ago?

 

[buyyouabeer]

Rust spots are a Ca deficiency. Something I never see after going to Jacks 321. I also wouldn't add any more plants to your tent, going to be a jungle as is.

 

[Ganggreen99]

The issue can be nutrient availability or it could be nutrient uptake. My money is on the latter.

If your nute mix is incorrect or if your soil is "defective" (if there is such a thing - I grow in hydro so mea culpa), the issue could be availability.

Nutrient uptake is driven, to a larger degree by, temperature and humidity and, to a lesser degree, wind speed. What's the weather like in there? Also, what has changed in the past few weeks, perhaps one or two weeks ago?

I'm growing in Fox farm soil. Not sure how to tell if it's defective. Temperature is 77F and 55Rh not much wind going on two small clip fans and an inline fan on low speed. Nothing really changed I'm thinking maybe my pH is off a little and possibly causing deficiency.

 

[Delps8]

I'm growing in Fox farm soil. Not sure how to tell if it's defective. Temperature is 77F and 55Rh not much wind going on two small clip fans and an inline fan on low speed. Nothing really changed I'm thinking maybe my pH is off a little and possibly causing deficiency.

That's helpful info though, because all the numbers are good, the benefit is that it helps rule things out.

This graphic can be helpful in terms of understand what makes things happen in a grow environment. Your temp+RH (VPD) values are good, you're not giving them too much wind (that can cause leaves to curl up but can also increase transpiration to unusual levels), and, if you've got an inline fan running, you're probably not in a situation of CO2 being too low.

"defective soil" - some growers make their own soils or buy soil that's got the wrong ferts in it. FoxFarm is highly reputable so that takes that out of the equation.

pH being out of whack can definitely make things go sideways. In soil, it's "measure the runoff" and it should be 6.5…I think. If the symptoms match a Ca def like @buyyouabeer has said that helps a lot. Then the question becomes what's causing the deficiency?

VPD is a common culprit but your numbers look good. One of the problems with just "adding X" is that it might not be a function of not having enough X in the ferts but of the plant being able to take up X.

Duh - watering practices - how much and how often? These are key and, since I'm a hydro grower, that stuff is all voodoo to me.

 

[Ganggreen99]

That's helpful info though, because all the numbers are good, the benefit is that it helps rule things out.

This graphic can be helpful in terms of understand what makes things happen in a grow environment. Your temp+RH (VPD) values are good, you're not giving them too much wind (that can cause leaves to curl up but can also increase transpiration to unusual levels), and, if you've got an inline fan running, you're probably not in a situation of CO2 being too low.

"defective soil" - some growers make their own soils or buy soil that's got the wrong ferts in it. FoxFarm is highly reputable so that takes that out of the equation.

pH being out of whack can definitely make things go sideways. In soil, it's "measure the runoff" and it should be 6.5…I think. If the symptoms match a Ca def like @buyyouabeer has said that helps a lot. Then the question becomes what's causing the deficiency?

VPD is a common culprit but your numbers look good. One of the problems with just "adding X" is that it might not be a function of not having enough X in the ferts but of the plant being able to take up X.

Duh - watering practices - how much and how often? These are key and, since I'm a hydro grower, that stuff is all voodoo to me.


View attachment 5438284

So I water every 3 days and I have smart fabric pots. I have a system I water on day 1.... train readjust or move stems around on day 2....And I do not touch plant at all on day 3 and repeat. I just checked my pH runoff and it is 6.0 exactly. I'm pretty sure my pH is just off. I usually give my plant 1 teaspoon of calmac per gal

 

[Delps8]

So I water every 3 days and I have smart fabric pots. I have a system I water on day 1.... train readjust or move stems around on day 2....And I do not touch plant at all on day 3 and repeat. I just checked my pH runoff and it is 6.0 exactly. I'm pretty sure my pH is just off. I usually give my plant 1 teaspoon of calmac per gal

pH of 6 is the new optimal (per Bugbee) for hydro but I think it's too low for soil, where 6.5 is the mark.

Re. dosage of CalMag - CalMag is part of a lot of nutrient formulations but the dosage will vary. If it's required for your fertilizer, great. If not, I would not add it.

I don't know where I read this but a Ca deficiency takes some time to manifest. The picture below is from my grow on 11/01 and there's a nutrient issue on some of the leaves at the front of the plant. I grow "high light and low nutes" so I thought that it might be a function of low EC. I was at 0.8 at the time. Also, it was only that plant that had an issue.

After increasing EC to 1±, the issue resolved a few days later.

I bring that up because it was isolated to a small part of one plant and it resolved quickly.

In your grow, how many of the plants are impacted and is there a progression or is it just one set of leaves? My thought on the latter is that it could be that something went sideways a week or so ago and it has impacted just one plant.