Greetings fellow cannabis lovers! I’m currently growing in a vivosun 2 x 4 tent. My space is limited unfortunately so it’s all I can do right now. I ran my first run of auto flowers recently. Due to a power outage for two days in my area, I had a lot of weird light cycle issues. 18/6 is what I ran but they had 30 hours of darkness and I thought it was a good idea to put a flashlight in the tent around the 30 hour mark. Power came on a few hours later and I forgot about the flashlight for a week give or take a few days. I’m fairly certain that event caused my plants high stress and made them herm out. I could be wrong but I don’t see what else could have been the factor.
Aside from that, I’m looking for some tips to increase my yields and avoid nute burn. I think I went too heavy with the nutes as I’ve read auto flowers do better with 1/2 strength or less.
Info about my space, I use Mills Nutrients and some Advanced Nutrients, typically I grow in foxfarm ocean forest or just plain pro mix bx. My in-line fan is currently setup to create negative air pressure, I have a 240W led Timber Growlight and I like to run fabric pots. Just recently I got a par meter for my phone so I’m able to get a decently accurate ppfd measurement shooting for around 150-300 for seedlings, 300-600 during veg and around 600-900 in flower. I try to maintain around 18 inches of height in the early stages and maybe bump up to like 24 later in flower. I have been feeding with tap water from my well and to be honest I haven’t been on top of pH. I have yet to pull a really good harvest as far as yield. The quality is always there, but I need to figure out how to increase my yields. I feel like maybe it has to do with my RH inconsistencies. I have a humidifier setup outside the tent but it has no set points. I also don’t have a dehu so I rely purely on my inline fam to help me balance out the moisture content in the air. Maybe I need to buy an RH sensor, humidifier with set points and a dehu with set points to help me have a more consistent environment? Any and all opinions are welcome. Thanks all!
I’ve never grown autos so I can’t really speak about them but I know that in general yield is heavily influenced by genetics. I get maximum yield from RDWC indoors and have some Thai in my outdoor plants to give them maximum size and yields. In dwc I use the Lucas formula and both indoors and out I add some soluble kelp and fulvic acid, both of these contribute to better growth and more pest and disease resistance.
Temps in the tent can have an effect, too cold and their growth is slowed, too hot and humid and mould becomes a problem. That said it’s often 35 degrees here and I just use fans and don’t have any issues with the heat.
Feed them nutrients gradually, start them on half strength, increase to 3/4 when they have a decent amount of leafy material and then full strength a week or so after that. Different plants will have different nutrient tolerance, so you can increase them slightly and wait a few days. I stop when the very tips of the leaves are starting to burn, but before you get any leaf canoeing.
Fulvic Acid will allow your plants to take up more nutrients so you can often push them much harder than with just nutrients alone.
Kelp will give you more branching and shorter squatter plants due to the cytokines in it.
Good luck!
If you are growing autos the light cycle is not as important as growing a photo plant. So I do not think that was the cause of the autos you had going herm. Where did you get the seeds from?
There are a few things you can do to help increase your final yield.
Proper trimming of your plant to allow light to make its way through the plants canopy.
Use the best lighting you can.
There are additives you can give your plants to improve yield. Such as molasses added to the water when the plant is in flowering.
As for nute burn, Only give your plants nutes when it needs it, no need to be giving your plants nutes every other day.
But that is my two cents on that. Take it for what its worth, happy to answer any other questions you might have.
From my understanding you can run autos on a longer light cycle, even 24 hours.
What genetics are you running?
Your ppm numbers seem high to me for autos. IF your ph is off the plants would be suffering noticeably. Depending on the levels, slow growth, slow drinking, leaves would look like shit with severe deficiencies and excess nutrients building, root rot.
Post some pics if you took any.
I’m pretty interested in this flashlight of yours that stayed on for a week. Please tell us about this amazing flashlight lol!
I have worked with a lot of growers who use autos to get 2 harvests per season in some more southerly states and the consensus among them is longer daylight hours=more yield. I tend to believe them, the number one thing you can do that will have immediate and measurable difference is to increase lighting. All the nutrients in the world won’t mean anything if the plant is maxed out on uptake because of limits to photosynthesis.
There are some good papers available on Google scholar that show yield increase as a function of light when all else is constant that are pretty impressive.
Hey @ThePotanist . I remember reading somewhere that a 6 hours light and 2 hours dark cycle would produce more growth because the plant was saturated with light after 6 hours and needed the dark to fix carbon. I simply can not remember where I read that. Have you ever seen research like that ?
First welcome to the forums, second might as well get a grow journal started once you hti a higher trust level you’ll be able to post more images if you run into that issue.
Now one question i haven’t seen asked is what do you define as a really good harvest, or what are your expectations vs what you have been pulling ?
Well my first harvest ever I had two feminized seeds and pulled 7.5 ounces dry total weight. Second harvest was full photo gg4 clones which pulled a measly 3.5 ounces dry combined. Autos are currently drying so the weight is tbd but I cut early due to impulsive decisions
@Magu I havent read that, but there is a lot of interest in alternate lighting cycles right now.
I would be suspicious of someone telling you the plant needs dark to increase photosynthesis. It does benefit some plants but they use a differently evolved photosynthesis pathway called the CAM pathway. Its essentially a tactic to conserve water, it is prevalent in many succulent and cacti species.
That being said, we are learning more and more photosynthetic pathways are not as set in stone as we thought. More and more we are finding plants that are facultative CAM. Normal photosynthesis most of the time, but CAM if needed.
Just because we don’t think cannabis is facultative cam, doesn’t mean it isn’t it just means we don’t have evidence it is.
Just as an aside thought. I am experimenting with using a PWM unit to turn a home made LED light on and off at specfic intervals. 5 seconds on and 10 seconds off. Im using it on seedlings. Should cut my electricity use by 30%. I read about it at “chilled - micro naps and light flickering for plants.” Im not trying to get much growth. Just keep them healthy until the sun comes back in late february.
Dont know anything about Autos but Reg Cannabis is a C3 Dioceceous plant that does not need darkness for Photosynthesis.I use 24 hours myself least i ever do is 20/4 sometimes thesedays for veg
I think all of us have gone through the same thing . Here’s what worked for me:
Grow in the largest pots you can. That has made a major difference for me.
Up-pot just before flip to reduce the chances of issues during flower (for photos), but plant young auto seedlings into their final, large pot.
Temps - never let an auto get below 65°F until after stretch. Once in full flower it’s okay to let them get cold once in awhile.
Keep epsom salts around and topdress a tablespoon or so at start of stretch and one or two times during flower, and keep some organic potassium granules just in case. I have to supplement occasionally, but only rarely with autos.
once you hti a higher trust level you’ll be able to post more images if you run into that issue.
