What are the main causes of mold on your plants?

As the title says, im wanting to get some insight on basically how to avoid any kind of mold. That being said what is some advice you guys have? Have you had mold before and if so what do you think caused it and how did you fix it or were you able to? Just knowledge based question i dont have mold but want to learn more about it so i can help others as well as myself if i ever get it. Fingers crossed...

Humidity & air circulation. Maintain an appropriate RH & regular gentle air circulation.

Cynister said:

Humidity & air circulation. Maintain an appropriate RH & regular gentle air circulation.

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When in flower what is the highest you can run your humidity? And lets say in a 2x4 tent is one 8" fan good enough?

Lack of air flow up thru the plants as well as at canopy level. Lack of air exchange affecting rh. Letting things get to dense.

Really all about air

Rootbound420 said:

When in flower what is the highest you can run your humidity? And lets say in a 2x4 tent is one 8" fan good enough?

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A good 4 inch is enough for a 2 x 4, 4x4 before you need a 6 inch

Spores temps and Rh.

In my situation i have a 2.5x4.5 closet. 4" vivosun ventilation fan and carbon filter pulling air from closet out. Then i have an 8" fan going to keep air circulation. Temps stay between 73 and 76 and humidity stays between 50 and 60%. Chances of getting mold? I have 2 in flower right now.

1 high RH
2 Bugs
3 dead leaves left to sit in the buds.

In a 3'x4' tent with a 400w LED, I can hold the RH at 50% - 55%, temp at 77F - 80F with a 6" inline fan exhaust drawing air from the top exiting outside and a filter over the intake vent drawing air from the bottom. Also, I'm running 2 small low speed fans for circulation inside the tent. Both are mounted half-way up the tent poles on opposite corners; one blowing down toward the floor and the other blowing up towards the light, thus keeping air circulation and temperature relatively the same throughout the tent. The outside makeup air is from the surrounding room and that is usually right at 72F with RH varying from 45% - 60% depending on weather. This is a simple, passive system that has been working for me for some time. 2 autos with LST fill the tent easily. In this set-up a 4" inline fan would be sufficient.

What is humidity outside tent? Without a dehumidifier, your extractor should try to get as close to that as possible. Are you venting into the room that tent is in?

JoeBloggs said:

What is humidity outside tent? Without a dehumidifier, your extractor should try to get as close to that as possible. Are you venting into the room that tent is in?

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Humidity in the room is 45-50%. Closet has plenty of air flow for sure just worried about the humidity at times. If i water the plants itll go up to 58% for about a day them work its way back down to 50%

How do sativas grow in jungles but not mold? Air flow!

Air flow is critical to avoid rot.

They’re microclimates just around the buds themselves. The humidity is higher in the buds than the air surrounding them. If insufficient airflow is present the humidity collects then rots from the inside out.

So you can run higher humidity with great airflow.

Simpler way to avoid it is running a lower humidity in the tent but that can spike in the night cycle so airflow again is the most important factor!