Calcium/Magnesium deficiency? Week 3 flower

[giotto420]

Hello. I am around week 3 into flowering and have noticed some deficiency starting to appear on my plant - few brown spots are appearing on different leaves (both from the top and from the bottom of the plant), and yellow leaves also started yellowing and are really fragile and crumbly.

I am attaching some photos to help with ID and some info about her below;

• Soil - Klasmann TS3 Sphagnum Peat Moss/Substrate mixed with some perlite and vermiculite
• Lights - 20:4 from 300W LED (real 135W)
• Light distance: ~ 40cm from canopy
• Water: I am using tap water that as far as I know is considered 'hard water', and has natural pH of around 8+. I use ph down to bring it down to ~ 6.5 before watering

I water as soon as I feel the pot be light and the top of the soil dry (usually happens every 3 days).

• Exhaust pulling hot air at the top of the tent
• Age: 7 weeks and 3 days
• Temps: 21 - 27 Celsius max
• RH: 45% - 50%
• Nutes: Biobuzz Bloom (1ml / 1.5L) & Top Max (1mL / 1.5 L) + Fish Mix (0.5 ml / 1.5 L)

I am also growing another one, which is around 3 weeks old and seems to show similar (?) deficiency as well... also attached photo of her as well.

From the research I have done, it is possible that it is Magnesium deficiency which would be pretty weird as like I mentioned, the water I have should be hard water.

Can anyone help me address this issue?

This here, is one of the bottom leaves that I have removed:

 

[mysticepipedon]

At the beginning of flower there is a demand for N, Mg and Ca. What you are seeing may be a slight deficiency is N and maybe Mg.

What are you feeding them? I wouldn't do anything drastic. You might slightly increase the dose of nutrients and maybe ad 1 tsp/gal of epsom salts next time you water.

EDIT: I suddenly realized that you offered no information on your media or what you are feeding them. Maybe explain a little of that before taking any of my advice.

 

[giotto420]

At the beginning of flower there is a demand for N, Mg and Ca. What you are seeing may be a slight deficiency is N and maybe Mg.

What are you feeding them? I wouldn't do anything drastic. You might slightly increase the dose of nutrients and maybe ad 1 tsp/gal of epsom salts next time you water.

EDIT: I suddenly realized that you offered no information on your media or what you are feeding them. Maybe explain a little of that before taking any of my advice.

How come I offered no Information? It is quoted in the post.

Resending;

Soil - Klasmann TS3 Sphagnum Peat Moss/Substrate mixed with some perlite and vermiculite

Nutes: Biobuzz Bloom (1ml / 1.5L) & Top Max (1mL / 1.5 L) + Fish Mix (0.5 ml / 1.5 L)

Water: I am using tap water that as far as I know is considered 'hard water', and has natural pH of around 8+. I use ph down to bring it down to ~ 6.5 before watering

 

[mysticepipedon]

How come I offered no Information? It is quoted in the post.

Resending;

Soil - Klasmann TS3 Sphagnum Peat Moss/Substrate mixed with some perlite and vermiculite

Nutes: Biobuzz Bloom (1ml / 1.5L) & Top Max (1mL / 1.5 L) + Fish Mix (0.5 ml / 1.5 L)

Water: I am using tap water that as far as I know is considered 'hard water', and has natural pH of around 8+. I use ph down to bring it down to ~ 6.5 before watering

I'm guessing the bloom nutes don't have much N. If that's the case, you might want to add a slight amount of veg nutes into the mix next feeding.

However, it seems like there's a window for when the plants will benefit from extra N during flower. You could be nearing the end of it.

 

[giotto420]

I'm guessing the bloom nutes don't have much N. If that's the case, you might want to add a slight amount of veg nutes into the mix next feeding.

However, it seems like there's a window for when the plants will benefit from extra N during flower. You could be nearing the end of it.

What makes you think it's a nitrogen problem? As far as I know, nitrogen shouldn't cause dark spots over the leaves and top leaves should not be affected at first, right?

 

[mysticepipedon]

I have no idea why you have a dark spot on that leaf. It doesn't look like a widespread problem.

Your bottom leaves are a little lighter in color than the top leaves. It's likely N or some other mobile nutrient.