Having trouble identifying the deficiency

syntax03f · Aug 14, 2021

Hi everyone!

I'm new to soil growing but I have been growing using hydroponics for over a decade. I have two mother plants currently of different genetics ~2.5 months old and both are photoperiods. The mother on the left is a hybrid of gorilla glue #4 and animal cookies (mostly Indica) while the mother on the right is a strain called herijuana (full Indica) and both seem to be showing similar deficiencies. I think they are both showing a lack of sulfur but I'm uncertain and I don't want to treat for the wrong thing. What do you all think? The curling of the left plant is what's really confusing me

My Setup:

2x4 grow tent
400w HPS w/ digital ballast set at 50%; 18/6 schedule
424 CFM blower
Average temp 70.4 F
Average Relative Humidity 46.8%
Soil is Fox Farm Ocean Forest potting soil
Nutrients Fox Farm Liquid "Grow Big" 6-4-4 watering 1 week on/off
Well water starting pH 6.4 which I balance down to 6.0 - 6.2 pH
Fabric 5 gallon pots
Soil probe shows soil at 7.0 pH

syntax03f · Aug 17, 2021

So I've been looking through other related posts and now I'm leaning more towards over watering and it's causing a combination of deficiencies. I'm currently watering these girls every day between .5 - 1 liter. I didn't water yesterday, as a test and noticed today both girls we're drooping badly so I gave them a little more than normal and they both perked back up and actually look a bit better.

I'm mixing CalMag with Big bloom (heavy supplement) with well water which worked out to 6.2 pH on its own.

Next week I'll plan on a plain well water cleanse and see how that goes

Moshmen · Aug 17, 2021

syntax03f said:
So I've been looking through other related posts and now I'm leaning more towards over watering and it's causing a combination of deficiencies. I'm currently watering these girls every day between .5 - 1 liter. I didn't water yesterday, as a test and noticed today both girls we're drooping badly so I gave them a little more than normal and they both perked back up and actually look a bit better.

I'm mixing CalMag with Big bloom (heavy supplement) with well water which worked out to 6.2 pH on its own.

Next week I'll plan on a plain well water cleanse and see how that goes

Great place to start - also any idea what ppm your well water is ? How much calmag you feedin?

garybo · Aug 17, 2021

syntax03f said:
So I've been looking through other related posts and now I'm leaning more towards over watering and it's causing a combination of deficiencies. I'm currently watering these girls every day between .5 - 1 liter. I didn't water yesterday, as a test and noticed today both girls we're drooping badly so I gave them a little more than normal and they both perked back up and actually look a bit better.

I'm mixing CalMag with Big bloom (heavy supplement) with well water which worked out to 6.2 pH on its own.

Next week I'll plan on a plain well water cleanse and see how that goes

Nice job of searching for a diagnosis of your problem and getting back with your find. Closure is polite.

Keepitgrowing247 · Aug 17, 2021

syntax03f said:
So I've been looking through other related posts and now I'm leaning more towards over watering and it's causing a combination of deficiencies. I'm currently watering these girls every day between .5 - 1 liter. I didn't water yesterday, as a test and noticed today both girls we're drooping badly so I gave them a little more than normal and they both perked back up and actually look a bit better.

I'm mixing CalMag with Big bloom (heavy supplement) with well water which worked out to 6.2 pH on its own.

Next week I'll plan on a plain well water cleanse and see how that goes

Check out this thread..

Understanding VPD and Transpiration Rates for Cannabis

Transpiration is the loss of water from a plant in the form of water vapor. Water is absorbed by roots from the soil and transported as a ...

www.thcfarmer.com

syntax03f · Aug 17, 2021

Moshmen said:
Great place to start - also any idea what ppm your well water is ? How much calmag you feedin?

Thanks! well water is 75 ppm on its own. With the current nute combo the total ppm is 860. I'm adding 5ml / gal of calmag and I'm using 4 tsp / gallon of big bloom

syntax03f · Aug 17, 2021

Keepitgrowing247 said:
Check out this thread..

Understanding VPD and Transpiration Rates for Cannabis

Transpiration is the loss of water from a plant in the form of water vapor. Water is absorbed by roots from the soil and transported as a ...

www.thcfarmer.com

Wow thanks! This is really useful. Considering all these factors, I think the temperature is okay but the overall RH is on the low side. The soil I use does already have perlite but I could try adding more. I've also moved the light up further away.

I have the blower connected to a tube container around the HPS lamp and I just have the intake open into the tent while I could connect the other end to another duct bypassing the tent all together which would remove excess airflow and boost the RH in the tent - I hadn't considered that!

syntax03f · Aug 25, 2021

I wanted to give a promising update on what I've done and the results so far. High VPD was the main area of concern with this setup by the rate of transpiration observed from skipping a watering day.

Plan for lowering VPD:

Adjust light schedule
I discovered my new timer was switched to always on so the mothers were actually on a 24 hour lighting schedule so I've corrected this back to an 18:6
I mist the mothers thoroughly several times a day with a bottle mister with untreated well water
I also increased the light distance by several inches

Observations from lowering tent VPD:

Rate of transpiration has been significantly lowered in that I can skip watering by a whole day and average RH by night has increased
New growth on both plants appear normal and healthy (see attached images)

I've also continued the supplemental nutrient feeding to account for overall nutrient loss due to the high VPD.

In summary these suggestions were very helpful! Thank you all! Happy growing

Having trouble identifying the deficiency

Having trouble identifying the deficiency

syntax03f

Attachments

syntax03f

Attachments

Moshmen

garybo

Keepitgrowing247

Understanding VPD and Transpiration Rates for Cannabis

syntax03f

syntax03f

Understanding VPD and Transpiration Rates for Cannabis

syntax03f

Attachments

Having trouble identifying the deficiency

Having trouble identifying the deficiency

syntax03f

Attachments

syntax03f

Attachments

Moshmen

garybo

Keepitgrowing247

Understanding VPD and Transpiration Rates for Cannabis

syntax03f

syntax03f

Understanding VPD and Transpiration Rates for Cannabis

syntax03f

Attachments

Privacy & Transparency

Privacy & Transparency