Regarding Nutrient PPM

[tronN00dles]

Hey folks,

I often see recommended TDS for autoflower nutrient solutions at various stages of growth posted online. For example, I've seen a few people on here state not to exceed ~550 PPM during flowering. My question is this: does 550 PPM apply to certain mediums only, or is it universal? If I'm growing in soil, should I be shooting for a lower nutrient TDS count than if I were growing in hydro, as the soil itself would increase the TDS of the nutrient solution upon fertigation, would it not? I'm currently using Pro-Mix HP, which I know contains, at the very least, some dolomite lime. Is a nutrient solution of 550 PPM still the upper limit for Pro-Mix HP, or should I be aiming lower?

Cheers,

tronN00dles

 

[Mañ'O'Green]

Hey folks,

I often see recommended TDS for autoflower nutrient solutions at various stages of growth posted online. For example, I've seen a few people on here state not to exceed ~550 PPM during flowering. My question is this: does 550 PPM apply to certain mediums only, or is it universal? If I'm growing in soil, should I be shooting for a lower nutrient TDS count than if I were growing in hydro, as the soil itself would increase the TDS of the nutrient solution upon fertigation, would it not? I'm currently using Pro-Mix HP, which I know contains, at the very least, some dolomite lime. Is a nutrient solution of 550 PPM still the upper limit for Pro-Mix HP, or should I be aiming lower?

Cheers,

tronN00dles

Yes, 550 PPM is all you need for an Auto. How you fertigate is important In the the Pro-mix HP you need to start slow and ramp up to the 550 PPM and only fertigate every third or fourth watering. Fertilizing correctly in pre-charged soils is an art form because you really never know what is actually in the pot.

 

[tronN00dles]

Yes, 550 PPM is all you need for an Auto. How you fertigate is important In the the Pro-mix HP you need to start slow and ramp up to the 550 PPM and only fertigate every third or fourth watering. Fertilizing correctly in pre-charged soils is an art form because you really never know what is actually in the pot.

To add to this discussion, here is a snip of an analysis of Pro-mix HP:

Take calcium for instance. I understand 80-140ppm is an acceptable range for calcium-containing nutrient solutions. The above analysis is based on a 'Saturated Medium Extract', which presumably was done with "new" medium. My next questions is this: would these calcium levels persist ~12 weeks or more for the duration of a grow? If so, it looks like extra calcium wouldn't be needed with soft or RO water would it not? Assuming the calcium comes exclusively from the added dolomite lime, is it reasonable to expect calcium levels to remain in this range for the duration of a grow without supplementation?

-tronN00dles

 

[Proph]

To add to this discussion, here is a snip of an analysis of Pro-mix HP:

View attachment 1304391

Take calcium for instance. I understand 80-140ppm is an acceptable range for calcium-containing nutrient solutions. The above analysis is based on a 'Saturated Medium Extract', which presumably was done with "new" medium. My next questions is this: would these calcium levels persist ~12 weeks or more for the duration of a grow? If so, it looks like extra calcium wouldn't be needed with soft or RO water would it not? Assuming the calcium comes exclusively from the added dolomite lime, is it reasonable to expect calcium levels to remain in this range for the duration of a grow without supplementation?

-tronN00dles

There are a lot of variables ti that question, but in general, no.. Start thinking of your plants as the living, breathing, feeding beings they are.. It makes things easier, trust me, lol. If you have a plant that is actively feeding.. All levels should be decreasing. Calcium is a secondary nutrient. It's not used in high volumes like NPK is.. The ca ppm levels will decrease.. But calcium is in so many things that any "normal" feeding schedule will keep ca, and other nutrients at a decent level. I've personally never "needed" to add calcium. If you do, like you said, it's in your tap water.. So that's always an easy fix

 

[Mañ'O'Green]

To add to this discussion, here is a snip of an analysis of Pro-mix HP:

View attachment 1304391

Take calcium for instance. I understand 80-140ppm is an acceptable range for calcium-containing nutrient solutions. The above analysis is based on a 'Saturated Medium Extract', which presumably was done with "new" medium. My next questions is this: would these calcium levels persist ~12 weeks or more for the duration of a grow? If so, it looks like extra calcium wouldn't be needed with soft or RO water would it not? Assuming the calcium comes exclusively from the added dolomite lime, is it reasonable to expect calcium levels to remain in this range for the duration of a grow without supplementation?

-tronN00dles

Yes this is what I am talking about after a few weeks what is left? I have no way of knowing.

 

[tronN00dles]

Yes this is what I am talking about after a few weeks what is left? I have no way of knowing.

I reached out to Promix directly. Here's what they had to say on the matter:

"Dear tronN00dles, these numbers are as is out of the bale. We add a complete, water soluble, starter fertilizer charge that last about 7-10 days and then you would start adding fertilizer. Calcium is added as calcium nitrate (which is the majority of the calcium) and limestone (a minor calcium source). Calcium quickly declines either through leaching with water or plant usage. You will need to add calcium after a few weeks as the residual coming from the limestone is not enough to sustain normal plant growth. Also all the starter fertilizer in the product declines naturally as the product ages due to microbial activity, so the actual starting level of calcium when you use the product could be less than the posted range."

Straight from the horses mouth!

-tronN00dles

 

[Mañ'O'Green]

Well 3500 PPM is not diminished .

 

[tronN00dles]

Well 3500 PPM is not diminished .

Did you mean to post that on a different thread? Hehe. I did a search and found the post regarding a high ppm run-off. Not sure what’s up with that. I’m 7 weeks into a grow - putting 500ppm in, getting 550ppm out, which makes sense based on what Promix is telling me.

-tronNoodles

 

[Mañ'O'Green]

Did you mean to post that on a different thread? Hehe. I did a search and found the post regarding a high ppm run-off. Not sure what’s up with that. I’m 7 weeks into a grow - putting 500ppm in, getting 550ppm out, which makes sense based on what Promix is telling me.

-tronNoodles

Probably

 

[MassMom]

Did you mean to post that on a different thread? Hehe. I did a search and found the post regarding a high ppm run-off. Not sure what’s up with that. I’m 7 weeks into a grow - putting 500ppm in, getting 550ppm out, which makes sense based on what Promix is telling me.

-tronNoodles

I find this chart real helpful