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Best bloom nutrient ratio for bud rot pervention

samiam

Member
So been running the jacks 5-12-26. But because of the high nitrate you have to add with the 15-0-0 I get alot of pm and bud rot in flower.

I already add sillica with every feeding, and my environment is dialed in a sealed room.

I run 1200 ppm co2
Lights on temp 85
Lights off temps 78
4 tons mini split AC
Dehumidifiers run 24/7 keeping RH @ 40-50%
A 4" exhaust fans runs at night to help vent out any stagnet air.
Fans below and above canopy for air circulation.

Only thing I can think of is this jacks causing the bud rot problem with to much k and N.

So anyone got any suggestions?

These are sativa Dom crosses I grow.
Same ones my buddy grows in a GH in bare ass dirt and gets very little if any rot at all.
 

maimunji

Active member
Read little more about botriytis. I can't see how nutrients can affect this shit. Jack, Canna or GH does nothing about your problems.
 

bigtacofarmer

Well-known member
Veteran
Good clean airflow, keep humidity under control.

For me whenever I run a strain that puts on baseball bat colas I have to be extra careful.
 

samiam

Member
I have, botriytis development is optimal in cool humid conditions above 55% RH. especially when you don't keep your lights on and off temps within 10f.
My RH only spiks to 50 for a hour when I water, other wise it stays at 40 for the most part.

What than would you suggest I change in my environment?

Am I worng to say there is less disease pressure with lower N and K levels?
 
Last edited:
X

xavier7995

Have you considered dropping the calnit? I usually start cutting down the amount of calnit about 1/3 to halfway through flower and use only the base the last few weeks before flush. Sativas normally like a pretty low N level in general, standard feeds are a bit strong for them and normally a bit higher in N than you want.

That said, the nutrients are not going to have much to do with fungal issues, silica does help with resistance though. No real recommendations, but some sort of fungicide product added to your regimine would be a good idea, ideally a bio-fungicide. I use a product called actinovate, old thread but they talk about it here https://www.icmag.com/ic/showthread.php?t=239283

Works well but am in the market for a substitute.
 

samiam

Member
I use dosers and cut the calcium nitrate down to 50 ppm by week 7. Any sooner I see rust spots. I use RO water so the only CA I get is in the calcium nitrate. They go 9 1/2 weeks.
 

samiam

Member
My observation is that pm, bud rot only forms at the top of the plant on leaves getting the most light at least in my grow anyways.

If I don't start to cut the calnit back by week 5 the leaves get really dark green and pm takes off like crazy.

No, I don't know of any lab to send samples too.

Thanks I'll read up on those links.
 

samiam

Member
Being in rockwool, coco. I think what it comes down to is I'll need to reduce the k levels. I'm running nearly 30% k with the jacks and added sillica throughout the whole plants life.

With limited CEC of rockwool this should free up more sites for CA and mag.
 

clown baby

Active member
i had problems trying to run potassium silicate with jacks. Jacks alone has too much potassium.

potassium silicate is probably better as a foliar. Although that doesnt help you since you already have PM and bud rot problems.

I know people say don't use sulfur burners indoors, but sulfur burners made all my PM go away when i was growing in a damp basement. Burned up through stretch and it kept PM in check. Didn't cure it. but kept it in check.

Only cure, afaik, is myclo. and apparently thats a nono.
 

samiam

Member
I have 8 16" fans, some wall mounted, I only use a small 4" exhaust fan to vent the room only at night since it's a sealed room.
 

krood

Active member
ive had alot less problems since i started using a product called Regalia. its made by a company called marrone bio innovations. lookem up its a bit pricey. Sagamartha seeds website has some good info too.
 

Avenger

Well-known member
Veteran
Since you have never had your solution analyzed so you know what exactly you are applying to the plants, have you atleast calculated what you are mixing?

How much, by weight, of each component are you mixing into one gallon of working solution?

How frequently do you fertigate?
DTW or recirculated?
Rockwool or coconut coir media? somekind of mix of the two media?

making assumptions with out any data is not going to solve the problem.

PM and Bud Rot are two different afflictions.
Bud Rot or grey mold is Botrytis Cinerea
PM or powdery mildew is one of several fungi in the order Erysiphales

Which one is infecting your plants? both?
 

samiam

Member
I'm in Coco right now but switching over to rock wool.


I feed 3 times in flower #7 pots when the lights are on and every 18 hours in veg. I feed 350 ppm of jacks, 235 ppm of calnit, and 30 ppm sillica and recharge twice a week. All RO water.

I get both pm and bud rot.
 
B

bigganjabud

Are you keeping your fans running 24/7?

If your environment is on point and your supporting the branches with the biggest kolas then you shouldn't be having any problems

DO NOT RELY ON A 4" FAN AT NIGHT BY ITSELF

I'd say that was ya problem right there

Oversize your extract fan also your filter and intake fans

That's what I'd do to upgrade your environment and keep the things on constantly mate otherwise your just breeding the correct conditions for mould

Also I'd have spent on fans and filters first

I do not or have never ran Co2 also I've not had botritis
Since I oversized my rvk and filter

I think personally that you should look maybe more at grower error that nutrients mate as plant food does not cause mould
 

samiam

Member
Yes fans run 24/7
I shouldn't even have that 4" vent fan installed because I'm in a sealed room. I only just installed it 6 months ago in a hope that it might help.
 

Bwanabud

Active member
Yes fans run 24/7
I shouldn't even have that 4" vent fan installed because I'm in a sealed room. I only just installed it 6 months ago in a hope that it might help.

[FONT=Arial, Helvetica, sans-serif]I'd agree with [/FONT][FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif]bigganjabud, there's not enough ventilation...regurgitating the same air, or blowing it around in circles,,,doesn't change the humidity level, or possible spores floating around. You need to take a serious look at your intake/exhaust system, even when adhering to VPD method a truly "sealed" room...there has to be "flow" and "exchange" taking place, otherwise your humidity will become unmanageable...not only will molds grow on your plants, but the walls and ceiling will be next. [/FONT]
[/FONT]
 

samiam

Member
The air in the room is exchange every night by the 4" fan.

All the people I know that run sealed rooms here don't have any kinda intake or exhaust.

The point in having a sealed room.

I sized my room based on square footage number of lights, and plants. 18 plants in a 11 x 24. 10k light. 2 24000 BTU mini splits. 3 70 pint dehumidifiers. I also run heaters at night in the winter when the lights are off. This makes the AC come on at night to help out the dehumidifiers.
 

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