Dirtbags Hydroponics Thread.

[chemistry]

Found this vid on youtube, it lines up well with what I'm seeing as far as increased growth rate. A stall at the beginning then a growth explosion. I'm still in the early stages but the difference is clear.

I plan to get the irrigation manifold installed today and give these girls their second watering since transplant. They're up to eating every 2-3 days now, but I think it will be daily by early this coming week.

Wow, how fast did the plants grow during the dark period in this vid.

 

[Judaz]

Once the plants get going on rockwool topping them won't really affect them as long as they are at that point when they are just taking off. 1 day later they are going again. Veg in rockwool will have my plants ready within 24/25 days after topping usually somewhere between 24-30 inches on og strains. The one you growing now seems like its one of those shorter but bushier type of plants with big fan leaves and tight internodes. The green caps are great also for keeping fungus gnats at bay. Even if you don't add imid to treat them they have a hard time reproducing when they can't access the algae and moist tops that would develop without them.

 

[Dirtbag]

I've actually got 4 strains in here at the moment. 2 of them are short and bushy and two are taller, I've got the bushy ones in the center rows and the taller ones are on the outside rows.

These will only get 2 weeks after topping.. time will tell...

 

[Aqua Man]

@Dirtbag idk how much you follow VPD. But with the increased growth rates in hydro it's not hard to see it makes a big difference. If you get a chance do some tinkering after your settled in personally in soil I don't feel it would make near the difference it does in hydro. Also think this is part of the reasons some people feels it's bogus. I feel like the faster a plant grows the more you need to fine tune everything to get the most and the more impact these subtle changes make. Under lower light in soil I bet you can grow with 20% humidity without much issue not case in hydro.

 

[Dirtbag]

@Dirtbag idk how much you follow VPD. But with the increased growth rates in hydro it's not hard to see it makes a big difference. If you get a chance do some tinkering after your settled in personally in soil I don't feel it would make near the difference it does in hydro. Also think this is part of the reasons some people feels it's bogus. I feel like the faster a plant grows the more you need to fine tune everything to get the most and the more impact these subtle changes make. Under lower light in soil I bet you can grow with 20% humidity without much issue not case in hydro.

Oh I keep VPD well in check. Currently temps are 23-26c, RH is 60-65 and leaf temps are about 22-23c at top of canopy.

Balancing the VPD partly explains my odd layout. It was heavily considered when choosing total lamp watts, vertical vs horizontal lamps, and exhaust fan size etc.

 

[MIMedGrower]

I'm banking on it.

Uh oh. Too much stress. The plants will feel it. Bad environment. Better start over. ;-)

 

[MIMedGrower]

@Dirtbag idk how much you follow VPD. But with the increased growth rates in hydro it's not hard to see it makes a big difference. If you get a chance do some tinkering after your settled in personally in soil I don't feel it would make near the difference it does in hydro. Also think this is part of the reasons some people feels it's bogus. I feel like the faster a plant grows the more you need to fine tune everything to get the most and the more impact these subtle changes make. Under lower light in soil I bet you can grow with 20% humidity without much issue not case in hydro.

Last night i had droopy tips and some nute stress wrinkling going on. And the telltale signs of pointing up leaves that supposedly mean needs magnesium. Well im sure it means calcium but i raised the temp in my room from about 74 farenheight to Closer to 77 average and within a half hour the leaves relaxed. These are week 2 plants and have nutrients left in the soil.

The higher temp combined with the relatively low humidity of 45% helped he plants uptake what they needed.

This goes against this vpd guideline and most of my experience with these flowers does.

We do not grow foliage plants we grow flowers that like dry air for best results. Plus vpd range is good for mold not just the leaves.

 

[Dirtbag]

Uh oh. Too much stress. The plants will feel it. Bad environment. Better start over. ;-)

I'm banking on it in a carefree kinda way? lol

Honestly I'll be happy to pull whatever I pull, It is what it is, I'm not gonna get too put out if I flip them a little smaller than I'd like.

And I'm actively trying to not stress out as much. My life is fairly complicted outside of the growroom and sometimes I let it get the best of me. I've gone back and read some things I've posted and I can sense my tension lol..

 

[Aqua Man]

Last night i had droopy tips and some nute stress wrinkling going on. And the telltale signs of pointing up leaves that supposedly mean needs magnesium. Well im sure it means calcium but i raised the temp in my room from about 74 farenheight to Closer to 77 average and within a half hour the leaves relaxed. These are week 2 plants and have nutrients left in the soil.

The higher temp combined with the relatively low humidity of 45% helped he plants uptake what they needed.

This goes against this vpd guideline and most of my experience with these flowers does.

We do not grow foliage plants we grow flowers that like dry air for best results. Plus vpd range is good for mold not just the leaves.

Actually it goes with VPD. You can steer nutrient uptake as you did. But if the nutrient were adequate you wouldn't have to do that. It's a tool not a hard rule. Can lower VPD for to slow nutrient uptake and raise it to increase. In soil it's not going to be near as crucial as hydro. Where growth rates are much faster. You would have seen much more issues with lower nutes than you did.

In soil like I said previously it's not as big of an issue and many things contribute to mold. You use VPD all the time. That's why you try to achieve humidity that works for you. Or are you saying that growing in 20% RH is ok?

It's also varying VPD is not one set humidity and temp and changes based on growth stages. Would you start clones in 45% humidity? Or do you put em under a dome?

 

[Dirtbag]

Last night i had droopy tips and some nute stress wrinkling going on. And the telltale signs of pointing up leaves that supposedly mean needs magnesium. Well im sure it means calcium but i raised the temp in my room from about 74 farenheight to Closer to 77 average and within a half hour the leaves relaxed. These are week 2 plants and have nutrients left in the soil.

The higher temp combined with the relatively low humidity of 45% helped he plants uptake what they needed.

This goes against this vpd guideline and most of my experience with these flowers does.

We do not grow foliage plants we grow flowers that like dry air for best results. Plus vpd range is good for mold not just the leaves.

After week 2-3 of flower I totally agree with this, but up until then we are growing foliage plants. I've always had the best veg growth with slightly warmer temps and higher humidity, but in flower I like to dry the room out to 45-55% RH. My last speedy veg in promix and fabric pots I let the humidity get as high as 65-70% and temps up to 27-28c. These hydro plants will be in the same range next week. I know a guy running supplement Co2 who goes up to 80F/80RH!

Mold and mildew is an absolute concern though, I'd never recommend doing that without a sulphur burner. Ever. But with one, the difference in vegetative growth rate is substantial.

 

[MIMedGrower]

Actually it goes with VPD. You can steer nutrient uptake as you did. But if the nutrient were adequate you wouldn't have to do that. It's a tool not a hard rule. Can lower VPD for to slow nutrient uptake and raise it to increase. In soil it's not going to be near as crucial as hydro. Where growth rates are much faster. You would have seen much more issues with lower nutes than you did.

No. The nutes are adequate. The floor has gotten colder. Temp is a controller much more than humidity. These plants are very adaptable. Keep the roots happy and the plant is happy.

Most of these popular strains are originally from the side of a desert mountain.

 

[Aqua Man]

Plain and simple if you think VPD is not accurate you are doing it wrong and do not understand it. Probably looking at an online chart. Because VPD ranges based on growth stage and it absolutely supports 40-45% RH in flower. The problem is people don't use leafs temps and that is as I said just doing it wrong then blaming VPD

 

[Aqua Man]

No. The nutes are adequate. The floor has gotten colder. Temp is a controller much more than humidity. These plants are very adaptable. Keep the roots happy and the plant is happy.

Most of these popular strains are originally from the side of a desert mountain.

Have to disagree they go together. Temp affects humidity you can't change one without affecting the other that's why it's called relative humidity. It's relative to temperature

 

[MIMedGrower]

Plain and simple if you think VPD is not accurate you are doing it wrong and do not understand it. Probably looking at an online chart. Because VPD ranges based on growth stage and it absolutely supports 40-45% RH in flower. The problem is people don't use leafs temps and that is as I said just doing it wrong then blaming VPD

I cant blame vpd. I never heard of it until a forum thread.

Never read about it in years of reading about growing plants. Not in greenhouse guides. Not in indoor vegetable production stuff either.

I did read in rosenthals book that he had no difference in results with different humidity. He does not consider it a factor except to change medium management.

 

[Aqua Man]

I cant blame vpd. I never heard of it until a forum thread.

Never read about it in years of reading about growing plants. Not in greenhouse guides. Not in indoor vegetable production stuff either.

I did read in rosenthals book that he had no difference in results with different humidity. He does not consider it a factor except to change medium management.

Advancements in science... There is a load of science and studies to dispute his findings if that's what he wrote( I haven't read it yet). I have not read his book. It's as simple as clones.... Did he find no difference try to start clone in 20%rh vs 90+%?

Was this at every stage of growth or just flower?

 

[Dirtbag]

I'm not going to argue the science of VPD for indoor gardening, it's a well understood and utilized tool in greenhouse horticulture and has extremely sound science behind it. I did learn about it during my first year of production horticulture classes in college and all the greenhouses were either manipulating it or adjusting their feed rates and calcium levels based on what was achievable, whether it was for flowers, ornamentals or food crops.

I have zero doubt it also applies to cannabis, though the ideal ranges for each growth phase are still up for debate. Personally I've seen better veg growth with slightly higher temp and humidity, and better flower growth by reducing temp a degree or two and dropping RH.

 

[Aqua Man]

This is what I use. I did a thread on it @Dirtbag if ya want the link.
KPA

Seedling/clone 0.4-0.8 Veg 0.8-1.1 Early flower 1-1.4 Late flower 1.3-1.5

 

[Dirtbag]

I know I've shared this here before but here it is again. Everest explains it pretty much on the money.

 

[Aqua Man]

I know I've shared this here before but here it is again. Everest explains it pretty much on the money.

Oh yeah I seen that one also.

 

[MIMedGrower]

Advancements in science... There is a load of science and studies to dispute his findings if that's what he wrote( I haven't read it yet). I have not read his book. It's as simple as clones.... Did he find no difference try to start clone in 20%rh vs 90+%?

Was this at every stage of growth or just flower?

I dont remember the details. Sorry. The book is in my old computer.

But he tested it didnt affect yield or potency.

And that is what I see too. My rooms are not sealed and my house has bad insulation. There is much atmospheric change in this house.

I control it all to be about 67-70 degrees and 45-60% rh but it isnt that simple. The outside sure affects the inside.