Is this a calcium deficiency?

[moxley]

I keep having this problem with small orange/brown spots right after flowering. Pro mix HP, General organics biothrive and calmag. I’m watering every fourth day with ph 6.5 water.

[Catfish22]

Please give more info such as grow medium, strain, auto or photo, etc.
PS: Nice pics!

[PeterMatanzas]

Catfish22 I agree with, need more info. If you are consistently watering with pH 6.5 there are nutrients locked out.

[moxley]

Here are some more details.

1. This strain is Candy Kush Express Fast Flowering (photoperiod). Plant height is 18 inches tall.

2. Just started week 5 of flowering on a 12/12 schedule. Tent size is 3x1.5x5.

3. The light I’m using is the Spider Farmer SF-2000 on 75% setting, 16-18 inches above the plant canopy. It mentions plants may require additional calcium/magnesium with this light?

4. Temperature varies between 23-27c. Humidity in the mid 40 range during the day and higher at night above 50/low 60s. I always have fans keeping the air moving and an extraction fan running. Never had any mold issues after a few grows.

5. It’s growing in a 5 gallon smart pot and the medium is Pro Mix HP.

6. Water until run off every 4 days when almost fully dry. I’m watering with 6 litres of filtered cold water. Every water I feed as well, a few mL of Biothrive Grow and Bloom (I use both because just Bloom by itself was giving me N deficiency) and nearly 10 mL of Calmag. Then I use drops of PH Plus and check with a PH tool (target ph 6.5).

7. I checked the water runoff PH and it was 7.0.

8. Looking at my older used pots, it looks like they got some serious salt building up on the bottom/sides.

[SoOrbudgal]

Hiya moxley for some reason a few folks on this forum have recently had issues with the promixHP we don't know why not sure if it's a strain thing or what, these guys are good growers also. OK now to get to your plants health.....i would not feed anything at all at this point. Let them be really dry lift the pot you need to know if they are dry. Flush with alot of plain water, let them dry again not till they droop but pot is dry. Can we see the whole plant please? They look maybe crowded?

[Farmbuck]

I agreed with you SoOrbudgal. A good flush then after a bit of Cal-Mag like I did to salvage my grow.

[Rwise]

Do you have risers under the pots so they do not set in the runoff water?
What I see is a PH issue causing lockout. In at 6.5 and out at 7.0, maybe drop the input to 6.0 - 6.3 range.

[moxley]

Here are some pictures of my setup. I have a pot riser under there that you can’t see.

[JeffInCanada]

They are getting pretty far into flowering...the leaves are going to do some yellowing, browning especially at the bottom. It is normal, to a degree. You seem to have a great handle on this...use your skills...don't do anything drastic. You can bring them home to a good harvest. Buds are looking pretty nice btw.

[PeterMatanzas]

agree with SoOrbudgal, defoliate. The plant will breathe better. But like JeffInCanada says buds are looking nice

[PeterMatanzas]

also, be sure to mix up your watering pH. One day use 6.3, next time, 6.1, next 6.4 - this isn't exact, but you need to vary the pH

[moxley]

Quick update I flushed and defoliated.

[JeffInCanada]

Looking good to fatten up, nice trimming. You're gonna get a great harvest.

[moxley]

Here’s an update. Brown spots got much worse after flushing with plain water. I still can’t figure out the problem but if I had to guess

1) Underfeeding?
2) Expired nutrients?
3) Overwatering?
4) PH issue causing lockout?

I’m going to try a different nutrient brand and letting my pot dry out longer going forward.

[Rwise]

I had a couple of plants that looked this way, it was light fade from the LED. Maybe try what the MFG recommended. If that dont help back the light off a bit.