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How to Combat Mold

Gitane

Active Member
I've got an outdoor grow in a hoop house enclosed with mosquito netting. Will running a fan inside assist in keeping the moisture from causing mold due to our high humidity or should I just enclose it and put in a small humidifier?
thanks
 

Gitane

Active Member
Thanks Mr. Bones. The DIYer in me was hoping to do it on the cheep using a fan. The area is 24 sq. ft. so it seems there are some inexpensive humidfiers. I would be placing plastic sheeting to enclose the hoop house. Any idea if this will diffuse the sunlight intensity so as to give rise to other issues.? Thinking I need this in the last 4-6 weeks of flowering,
 

Lester Freeman

Well-Known Member
Plastic sheeting has no pores for air to travel through, depending on the type. You basically need as much "fluid airflow" as possible throughout your canopy. Fans can be a good help in creating a flow pattern.

If you're worried about powder mold in the vegging/early flowering stage you can use SNS-244 by our sponsor.

About internal bud rot, not much you can do about it other than prune/defoliate selectively as to increase the airflow to the buds. Especially if there is deep pockets of foliage that can trap moisture.

You would need multiple dehumidifiers to even have a chance of getting it under control.

With outdoor growing, sometimes we just deal with what we got. I'd stick with the mosquito netting and just put fans in and hope for dry days. That's about all we can do.

Covering it with a plastic sheet would trap moisture inside and if the dehumidifiers can't keep up with it than it will just create an environment that fungus will thrive in.

Mold within greenhouse interiors is not uncommon.

For now, I'd say put in some more fans, like 2-3 more fans and consider selectively defoliating lower leaves and small popcorn branches that would aid in creating a "flow pattern" and bring air from down below , up and through the bud canopy.

Hope this helps :Namaste:
 

Gitane

Active Member
Thanks Mr. Lester. Pretty much what I was afraid of. This bizarre spell of humidity in San Diego the last month just hammered my plants that were in the last weeks of flowering. I had to chop early and still lost about 30%. The next plants will be ripening around late September. Which normally is kind of humid nowadays. Hoping for the best.
 

Gitane

Active Member
When do you think I should start running the fans ? Flowering started mid July. All indica. Would like to make it to 25% amber. Bud Rot has previously caused early harvests
 

Lester Freeman

Well-Known Member
As soon as possible. They should be oscillating, perhaps one in each corner of the area.

We have been having killer moonsoonal moisture for the past couple months, and with the possibility of Il Nino coming your going to want to keep your indies dry :thumb:
 

Lester Freeman

Well-Known Member
Oh I misread your square footage. Only 24 square feet. So it's not as big as I thought.

I was high when I read it and thought something else that was much bigger. My mistake.

Yeah just one fan prolly. Post some pics of your set up and plants, would love to have a look at them.

Or if you would like to start a journal so we could all follow and help you prevent rot here is the link

https://www.420magazine.com/forums/journals-progress/82545-how-make-grow-journal.html
 

Gitane

Active Member
Thanks Lester. Not sure if this will post, but here is a pic of my hoop house. Got 2 fans running now for full coverage.. Possible rain in the forecast. I put sheeting over the top last month to keep the plants dry. One day I missed, plants were drenched so I ran the fans for 48 hrs to dry em out. That did cause all the hairs to go red, but trichome development stayed clear/cloudy. Even after 11 weeks they were maybe 1% amber.
Wondering if my technique has affected the trichome maturity rate: I veg clones under CFLS from Mid March to May 1, then go outdoors and flowering started May 11. One sativa pheno did revert a month later with a lot of stretching and messed up bud development, but the other hybrids continued budding
I'll try to work up the grow journal.
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Gitane

Active Member
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Lester: Here is the set up. Wonderful seeing your garden. How did you keep the mold away this year? (I'm 1.5 mi from the coast) Manicuring was tough this year due to many dead, dried fan leaves. Last year I had no such problem. Last year used miracle grow tomato fertilizer, this year Earth Juce 5 bottle line. Been told I had a mag lock out. Soil is Edna's Best organic who said its 6.5 ph, but the run off indicated 5.0 No mold issues last year, but humidity was not the Califlorida weather like this year. I tried to let two plants go an extra 10 days with 2 plants (to 12 1/2 weeks flowering) and ended up with a 75% loss. With the mold I've averaged about 2 oz per plant and was really shooting for more (still better than last year when my veg time was 3 weeks as opposed to 6 this year) Current plants were from seed that I germinated in April. Any other tips to get these to the finish line in one piece? thanks
 

Lester Freeman

Well-Known Member
I'm 500 yards from the crashing surf. So I have dealt with a lot of mold and worms (they go hand in hand usually)

A few tips in general for fighting the bud rot.

You need to do a lot of manual inspections of the colas. One technique that I use for quick assessment of colas is the "leaf tug test"

I will tug the fan leaves that directly accompany the main stem of a cola. Start from the bottom and work your way up.

If a fan leaf ever slides right out with little to no resistance (a seemingly healthy looking leaf), than that is an area where you will want to have a look inside. You want to get to the mold before it takes over everything.

Often times you will find a leaf that looks "partially dead" which is located toward the top of the cola (where it is most dense), those are good indicators of a problem. Test it by tugging it gently.

Now, unfortunately at the end of the day we are at the mercy of mother nature. We hope and pray for dry days and clear skies.

The biggest part about minimizing your loss is keeping up with your manual inspections.

Another thing you want to do is think about ways to increase the air flow ( like I mentioned in the beginning with flow patterns)

Sometimes that entails slight defoliations...

Another thing is that you need to choose your strains wisely. It is not wise to grow bushy, short, and clustered indica plants that have no evolutionary history of surviving and reproducing in a tropical region that is hot and humid.

So, I grow a LOT mostly ALL sativas. And I find the phenotypes that have nice "lanky" structures with buds that are "open but compact" but not SUPER tight. So the buds get good air flow and have less chances of mold.

I have not had any mold at all this year, maybe I'm lucky, but I know my strains have made a big difference. I predominantly have been growing a strain called KC-45 which is essentially a land-race sativa from Brazil, which is in the tropics of South America. So as you can see such a strain fits right into my microclimate being a hot and humid place right by the ocean.

And often times, like you said, you tried to let it go a few more days and that just ruined it. Part of adapting as an ocean grower is being able to time it correctly. Look at the forecast quite often, everyday even. Growing so close to the ocean has its good things and bad things, high UV makes concentrated resins nicely, but the morning fog could trap moisture in the buds. So letting them go for just a few days too long ( I think of it as being "greedy" and tell myself, "well I need to take what I can get, otherwise its all gonna be mold and worms) can be detrimental. Sometimes you just have to cut your losses and take what you can get if you are going to battle with such treachery.


But.... so far so good... If the weather permits and I can get away with it though I'll let my buds finish up exactly how they should.

It's one reason I have started using the light deprivation force flower technique, the spring and summer is more dry than Sept/Oct. when we harvest. And we almost guaranteed a storm in late Sept/Oct. So with this technique I am able to harvest buds all spring and summer with no worry of mold or worms (Not always the case, I have had a couple of early spring plants rot) So.... I have my ways of maximizing my harvests. Still experimenting around with strains and techniques, but I've definitely found something that works for me.


Just stay diligent. You should definitely have some air flow in that tent. you may want to consider completely opening up/clipping open the sides to the tent to get some air flowing through it during the day.


OK hope this helps. :Namaste:
 

Gitane

Active Member
Thanks. I can't recall a summer with this consistent humidity and rain ever. The mosquito netting eliminated my worm problem and concurrent mold when put it up last summer, it allows pretty good light and airflow. I use the same technique as you to check for mold and salvaged the 4 I harvested last month with a decent yield but I didn't get the tricome maturity I was shooting for. I 'force' flower by 24 hour light (cfl set up at night and put em outside during the day) from mid march to May when they go outside till harvest. The length of dark at that time seems to be enough to trigger flowering. Could I start even earlier and get a harvest in early July? I'll post something at the end of September and let you know how the fan technique works. A little concern with the electricity usage, running the fans 24/7 for the next 6 weeks but all in the name of science!
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