Dirt crop growing better than past hydro of same genetics.

[Nate_in_AK]

Current grow is a clone from the previous plant, so identical genetics. Same grow light and tent temperature, but I have let the humidity go up to 65% this round, but kept it below 50% with the hydro grow.

This seems like a dramatic variation for a 15% humidity difference, so I am inclined to conclude that I was probably not setting up the hydro properly somehow.

At the time, I thought the upcurled leaves in the hydro crop were due to their proximity to the light. Now I am suspecting it was something else.

The hydro grow yielded a fair crop, but the buds were smaller and less dense than I hoped for. The potency of the cured hydro flower is fair...mid shelf range.

TBH the dirt grow has been so easy in comparison to hydro that I may not go back...but I am curious about the underlying mechanism of what happened.

Educated guesses?

 

[ComfortablyNumb]

There are so many variables, unless you have some really detailed records, impossible to know for sure.
I'm an organic grower, so I know very little about hydro, but if you didn't make sure the plants got what they needed, that's a difference.
Soil provides 99% of whats needed. Water is the other 1%.

 

[Nate_in_AK]

There are so many variables, unless you have some really detailed records, impossible to know for sure.
I'm an organic grower, so I know very little about hydro, but if you didn't make sure the plants got what they needed, that's a difference.
Soil provides 99% of whats needed. Water is the other 1%.

Yeah, I realize it's not a scientific comparison, just curious what thoughts might be.

 

[Aqua Man]

Current grow is a clone from the previous plant, so identical genetics. Same grow light and tent temperature, but I have let the humidity go up to 65% this round, but kept it below 50% with the hydro grow.
View attachment 1137756
This seems like a dramatic variation for a 15% humidity difference, so I am inclined to conclude that I was probably not setting up the hydro properly somehow.

At the time, I thought the upcurled leaves in the hydro crop were due to their proximity to the light. Now I am suspecting it was something else.

The hydro grow yielded a fair crop, but the buds were smaller and less dense than I hoped for. The potency of the cured hydro flower is fair...mid shelf range.

TBH the dirt grow has been so easy in comparison to hydro that I may not go back...but I am curious about the underlying mechanism of what happened.

Educated guesses?

Dirt grow van definitely be easier but both depend on how well they are done.

I'm guessing the humidity was much more inline with VPD on the soil grow. This has an affect on how much and how well the plant can uptake co2.... and we all know co2 impacts growth rates.

I may be a bit bias but I am a huge believer in VPD after my own experiences testing various humidity and temp combinations. I found it to be very accurate with about a 5% slide either way depending on genetics. Basically can tell by the leaf structure which part of the acceptable range they will like best. Indica with big fat leaves prefer the higher (lower humidity) side of ideal... sativa with the skinny leaves prefer the lower side (higher humidity) of ideal. And most hybrid with leaves in-between fall smack dab in the middle.

Of course VPD also play a big role in leaf temps and leaf temps play a role in growth and health of the plants.

 

[Aqua Man]

Imo hydro is less forgiving but can be more rewarding in terms of growth rates. Soil is more forgiving but usually lower growth rates. But like I say it's all going to come down to how well either is done.

 

[Nate_in_AK]

Dirt grow van definitely be easier but both depend on how well they are done.

I'm guessing the humidity was much more inline with VPD on the soil grow. This has an affect on how much and how well the plant can uptake co2.... and we all know co2 impacts growth rates.

I may be a bit bias but I am a huge believer in VPD after my own experiences testing various humidity and temp combinations. I found it to be very accurate with about a 5% slide either way depending on genetics. Basically can tell by the leaf structure which part of the acceptable range they will like best. Indica with big fat leaves prefer the higher (lower humidity) side of ideal... sativa with the skinny leaves prefer the lower side (higher humidity) of ideal. And most hybrid with leaves in-between fall smack dab in the middle.

Of course VPD also play a big role in leaf temps and leaf temps play a role in growth and health of the plants.

Could VPD differences alone account for this much variation in growth?

 

[growsince79]

Current grow is a clone from the previous plant, so identical genetics. Same grow light and tent temperature, but I have let the humidity go up to 65% this round, but kept it below 50% with the hydro grow.
View attachment 1137756
This seems like a dramatic variation for a 15% humidity difference, so I am inclined to conclude that I was probably not setting up the hydro properly somehow.

At the time, I thought the upcurled leaves in the hydro crop were due to their proximity to the light. Now I am suspecting it was something else.

The hydro grow yielded a fair crop, but the buds were smaller and less dense than I hoped for. The potency of the cured hydro flower is fair...mid shelf range.

TBH the dirt grow has been so easy in comparison to hydro that I may not go back...but I am curious about the underlying mechanism of what happened.

Educated guesses?

Any difference in nutes? Nute uptake in hydro is way more dependent on ph. Soil seems to have a wider range and is somewhat more forgiving.

 

[Aqua Man]

Could VPD differences alone account for this much variation in growth?

Hard to say forsure but yes.... it controls everything from plant temps to nutrient uptake and a huge influence on co2 uptake which has a huge impact on photosynthesis.

Have you found those plants tolerate more light?

 

[Nate_in_AK]

Any difference in nutes? Nute uptake in hydro is way more dependent on ph. Soil seems to have a wider range and is somewhat more forgiving.

Honestly not sure how to compare, but now that you mention it, the last crop got a different brand of nutrients. I switched from Growth Science Nutrients to General Hydro FloraGro late in the last grow. This is probably a clue too, Duh!!

 

[growsince79]

Could VPD differences alone account for this much variation in growth?

IMO 15% makes a big difference. Be careful at the end if you have botrytis in the air. Where I live its everywhere. Open the door and it's back. Smaller buds at lower humidity and its not an issue. Big colas at 60%rh can get the rot no matter how much airflow I have. At 45%rh even the big colas are good.

 

[ComfortablyNumb]

Honestly not sure how to compare, but now that you mention it, the last crop got a different brand of nutrients. I switched from Growth Science Nutrients to General Hydro FloraGro late in the last grow. This is probably a clue too, Duh!!

That might have a tiny bit to do with it.

 

[Nate_in_AK]

IMO 15% makes a big difference. Be careful at the end if you have botrytis in the air. Where I live its everywhere. Open the door and it's back. Smaller buds at lower humidity and its not an issue. Big colas at 60%rh can get the rot no matter how much airflow I have. At 45%rh even the big colas are good.

I'm planning to taper humidity down over the next several weeks to finish the last 2-3 weeks at 45%.

 

[Aqua Man]

I'm planning to taper humidity down over the next several weeks to finish the last 2-3 weeks at 45%.

Depends on the temps imo. Finish I drop my temps and that means I'm hitting RH ranges of 45-50% going by VPD.

 

[Nate_in_AK]

IMO 15% makes a big difference. Be careful at the end if you have botrytis in the air. Where I live its everywhere. Open the door and it's back. Smaller buds at lower humidity and its not an issue. Big colas at 60%rh can get the rot no matter how much airflow I have. At 45%rh even the big colas are good.

How would I know if I have botrytis in the air? It's not something I am familiar with. I have no history of white powder mold that I ever noticed.

 

[ComfortablyNumb]

How would I know if I have botrytis in the air? It's not something I am familiar with. I have no history of white powder mold that I ever noticed.

Bots is Grey mold. Look around at plants outside with tight leave structures. If you have it, it's difficult to miss.

 

[Nate_in_AK]

Have you found those plants tolerate more light?

That was the uncertainty behind the upcurled leaf question. Seems like the current crop is more happier at the same light level.

 

[Aqua Man]

Imo it's no so much the humidity as the microclimates. Good airflow is key. I have flowered to the end at 65% with 0 issues but I always have good airflow.

 

[growsince79]

How would I know if I have botrytis in the air? It's not something I am familiar with. I have no history of white powder mold that I ever noticed.

For me, it's almost impossible to tell until the very end or even when trimming. It starts in the center of the main cola and spreads from there. In my world, it only happens on the huge, very dense colas. The smaller or looser colas are safe. I just bought a hepa air purifier to see if it helps.