First grow and plant issues, please help!

  • original bc blueberry, Seed bank
  • Method: sunshine mix #4 soiless
  • Vessels: Pots plastic 5g
  • PH of Water 5.8 ph, 5ml advanced nutrients part A &B grow, 5ml B-52 AN, 3ml 3% hydrogen peroxide, 1 tbsp of cinnamon all per 4L of … runoff 5.8ph
  • PPM/TDS or EC of nutrient solution if applicable…no
  • Indoor 4x4 tent
  • Light system : 315 lec 3100k 24hrs
  • Temps; 20-23°C
  • Humidity; 55-60%
  • Ventilation system; Yes, exhaust fan low continuous
  • Humidifier, 2 small fans running 24hrs
  • Co2; no
    4th week of veg. I have done a fair bit of lst and hst during their growth…

Hello i’m having some issues with my plants. I have noticed some gnats fungis type i believe. It’s an on going battle with them but not out of control. But im not sure if they are the culprit or if my soil and lack of nutrients is. Any input would greatly help. I also top dress the soil with DE and feed every 3-4 days depending on if needed.

I see some signs of overwatering. It’s hard for me to distinguish the discoloration / yellowing. It’s not normal to see such yellowing among older growth. Someone smarter than me should weigh in.

Some folks use Captain Jacks for pests. It’s safe to use. I can’t comment on fungus other than to say watch your humidity, temps, and airflow.

Not much help, I know. I’ll leave you with a couple of charts and someone else can probably get more specific.


The best treatment for fungus gnats is BTi. It’s available in a pure powder on eBay. 2oz is enough for most infestations. Or, if you’re in a hurry, mosquito bits contains a diluted amount of BTi.

Also, is the sunshine mix a soil? If so, your pH is way too low. 6.5 is the soil sweet spot.

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Soiless Canadian sphagnum peat moss, coarse grade perlite, gypsum, dolomitic lime are the ingredients. I was told to treat it similar to hydro hense the lower ph.

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I will maybe try the mosquito dunks. I also have neem oil on hand i was thinking of mixing into the feed. Im open to all quick options but want to stay on the safe side as in more organic. Was thinking about some kind of neem and essential oil mix or something.

Honestly, the BTi is so effective I wouldn’t even bother with anything else. It takes about 2 weeks to break the cycle.

No shit eh. I will have a look. Harder to find certain things in canada and i want to flip these girls soon. They are recovering from trainning and suoer cropping so i have a wee bit more time i guess…gave them a molasses foliage last night and they seemed to like it bit more perky today.

I agree.

You have a number of leaves that could be removed, improving light and airflow. You do not have enough light to flower that space FYI. You need 800 watts from the wall and currently at 300.

Plants do not particularly like to be left in 24 hours of light; some processes do occur during lights off cycle. With adequate light you can run 16/8 and hit your DLI.

Fungus gnats are a sure sign of overwatering. I would strongly suggest you change your watering practices to reflect this. A good dose of straight 3% peroxide into the soil (less) media will kill larva that may or may not be attached to your roots and depriving the plant of nutrients. A follow up dose of Mykos will reestablish the soil (less) biota after peroxide.

You also have a cal mag issue and I didn’t see you adding any? Are you running silica? Are you flushing? These are all things needed to be successful in coco.

This would be very similar to Promix and should be PH’d to an intermediate number of 5.8 to 6.2 or so: FYI it is really not hydro. Feedings should be in the 900 ppm range at peak and I target 6.0 for my media grows.


I flushed 2 weeks ago due to a low ph issue and was going to flush after a bit of recovery. I did feed 5ml cal-mag a week ago. Maybe i should keep that a a regular feed. Ive been letting them dry out pretty good. Pots weigh next to nothing when i water. And dry down to the first knuckle. No silica. As for the light it will have to do and has done pretty good till now. I know guys getting 1-2 pounds off same light same tent. I was thinking of adding some vertical leds on the sides. Any suggestions?

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Killing it with kindness.

Could you be more helpful?

Feed/water/feed/water, use R/O if possible, PH’d to 6.0. Cal mag on water days. Normally 2.5 ml/gal should do.

Fungus gnats (based on your description) are absolutely a sign of over watering which, ergo, means you need to go longer between waterings. You would be surprised at how much moisture is present and still feels dry.

Silica is a good additive to prevent issues like stem rot and pests.

A 315 watt LEC is totally inadequate for a 16 square foot space. If you are only using 1/2 of it you will do alright. BUT! I need to remind you that you asked for expert advice which includes lights. Your ‘guy’ that grew 1 to 2 pounds would have likely grown 3 to 4 pounds with adequate lighting in the same space.

Once again; another 315 would do pretty well and if adding LED’s just supplement your canopy. Side lights do only marginally and under lighting is a waste of energy as the leaves do not absorb photons from the bottom.

It is a high value but not sure what value this statement added?


The plant will grow directionally towards light. The buds will grow downward if is where the light source is coming, but you would run into heat issues as it would be rising toward the plant.

Thanks man i appreciate the great info. Ya i kinda got what i got when i bought. And id love to get more light but im stuck with what i have now. I will definitely try what you guys suggested and hope i can go into a healthy flowering stage! If i was to upgrade lighting. Would a 630 lec be a good choice? I could then use the 315 for a veg tent as i add on! Also cal mag all the way through flower?


This chart came out of a free book you can download online.

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From a coverage standpoint you might be better with two smaller fixtures. If heat is not an issue then the LEC is a fine choice. If you have heat issues then I might suggest a high end LED like the HLG 550, but that is a bit more pricey.

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Heat is no issue. My sunsystem 315 lec right now barely gives off any heat. Do the external ballast controlled units tend to dish out lots of heat? I’ve been looking at hlg and kingbright led lights. I just dont know anything about led and if they are worth it.

I could see 1 unit, but 2 I would say someone isn’t telling whole story. They are nice lights, but output still limited. You would probably have to run autos on long light schedule in hydro to repeatedly do that.


Could you please offer a lighting suggestion for my 4x4x6 tent to help me put on more flower weight if all else goes well. I wish my tent was taller but i will get another one soon.


@dbrn32 is the man to know for lighting.

Let's talk DIY lights

That would be a great thread to peruse when you can.