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When should I start the 18/6 & 12/12 light/dark cycle?

BikerBear

Member
Hi Everyone,

Newbie, first time grower here... My girls are looking quite nice and lush, but when do I start the light/dark cycle to encourage flowering/budding??? Is there something I should be looking for on the plant? Or just start the cycle when I "feel" it's time???

My girls are in soil kept in a grow tent using red/blue LED grow bulbs (2x) and 6500K daylight bulbs (5x); currently on 24-hour lighting.



I've read here to start with an 18/6 (light/dark) cycle for the first couple of weeks; then transition to a 12/12 cycle.

Just don't know when to start....



Many thanks in advance!

:thanks:
 

Greenethumb42

New Member
If I was you I would switch now to the 18-6 and run that for a week or so till you switch to 12-12..plants need time to sleep even if it's only 3 or 4 hours..I was told that roots grow more in the dark period then when the lights are on..and really when to start budding is up to you..all depends on how much room you have cause ones you switch to 12-12 there gona double in size..I would say at least veg for 4 to 5 weeks before you do the switch...I let my girl go 5 weeks veg and she flowerd for 11 weeks..harvested 170 grams of 1 plant...300 watts cfl..5 gal smart pot
20160405_004318.jpg
 

BikerBear

Member
Thank you very much Greenthumb42! I'll start the cycle tonight, as my girls are about the same size as the one in your pic above... Finally!!!! Maybe I'll have some herb....

:cheer:
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016 - Photo of the Month: Nov 2020
Sorry I actually wrote out a reply to your post after you first made it, but got waylaid and then didn't see this thread again till now. Here it is, fwiw.

Plants have to reach maturity before they can flower, and that's at anywhere from 3-7 weeks of age but usually around five in my experience. Usually they show maturity by growing a few pistils (or balls) - ie preflowers. So a lot of people veg for a month or so to reach that sexual maturity before they switch the lighting. You can switch to 12-12 sooner, or even grow 12/12 from seed. They'll be smaller because of the shorter days but they still won't flower till they reach the right age.
The main determination though is the amount of room in your growing space. Plants will usually roughly double in size after switched to flowering mode. There are a few things to juggle-overall grow room space and height, available light, and matching the pot size to the plant.
 

BikerBear

Member
If your is the size of mine now then it's gona get really big when you go 12-12..that pic of mine was the day I cut her down...how old is your girl now

Hi Greenethumb42, my seeds were planted on 15th April. So, they're about 9 weeks old now. As Weaselcracker mentions above about the pistils, my girls are not showing any pistils yet. But, the aroma in the grow tent is awesome! I go in for a daily sniff... :drool: because I absolutely love the fragrance.

Should I hold off transitioning to the light/dark cycle until I start to see the pistils appearing??? I don't want to do anything that may cause any harm to my girls; not after all of this effort!


I've got plenty of room in the tent as it's 2m-sqare by 2m tall.


:thanks: BOTH!!!
 

OlderGrower

Member of the Month: Dec 2015
2m x 2m is a far cry from being able to say "I have all the room I will ever need to flip into flower" Yes plants do stretch when they get thrown into flower but not all strains are equal, some will stretch a little and some seem like they never stop. Here is an example, my Huckleberry was around 5x5 feet wide and around 3 1/13 fee tall when I flipped her into flower in my 5 ft x 10ft x 6.5 ft tall tent. I had 3 other plants in with her which were all small roughly 18 inches above the buckets, (I grow with DWC bubble buckets) I was worried that when I flipped them that the Huckleberry was going to take over the room and push out the other 3 plants, Wrong. It was not the Huckleberry that is the problem, it is doing just fine, but one of the 18" plants which is a Sativa landrace has gone ape shit bat crazy I had to build a makeshift scrog on my buckets to contain her. My lights over her are max'd out and she has a foot print now of over 4 foot by 4 foot and is within 6 inches of my lights which I had to modify so I could raise them an extra 6 inches because the plant literally was touching the light. I have no way to modify my lights anymore, the only option left is to pull the branches down which will increase her foot print which I am pretty much max'd at also.

There are many factors that need to be considered when deciding when to flip. another one is how much light at you running with, more light means more stretch, a plant under 300 watts of light will not stretch as much as say a plant of the same strain under say 1000 watts of light.

On ones 1st grow, one wants to be successful and that should be their number 1 goal, yield and quality should be on the list but not their top priority. As you grow more and gain experience, your priorities will change, but as they do, you will have a much better 1st hand experience of what to expect.

Best of luck to you and hope your 1st grow is a great success.
FYI you were given very solid advice before I posted from Weasle and the the others, I just added my 2 cents
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016 - Photo of the Month: Nov 2020
They don't always show preflowers. Usually mine do if I'm not training the hell out of them. In any case, they're definitely old enough to flower now and will show isex after changing the light cycle.

Should I hold off transitioning to the light/dark cycle until I start to see the pistils appearing??? I don't want to do anything that may cause any harm to my girls; not after all of this effort!
As I wrote in my last post you can put a plant into 12-12 at any age, including growing under that cycle from seed. No it won't hurt them in any way. You're going to have fairly tall plants so you'll probably have to be doing some training. Maybe you have been doing some already. Looking forward to the photo and if you have any info in the strain that'd be helpful too. :thumb:


Edit- oh pics are up I see...
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016 - Photo of the Month: Nov 2020
Mmmm.. More questions I'm afraid.
Can you tell us more info about the plants like what you are growing them in, what you're doing for feeding, temperatures, ph of water and feedings (?), and strain if you know it? How many plants do you have?
 

BikerBear

Member
Mmmm.. More questions I'm afraid.
Can you tell us more info about the plants like what you are growing them in, what you're doing for feeding, temperatures, ph of water and feedings (?), and strain if you know it? How many plants do you have?

Hi Weaselcracker,

Info on plants....

Growing medium is soil, with vermiculite; very well drained
Feeding with Miracle-Gro liquid fertilizer
Water pH is in the range of 6.5-6.8; according to the meter I use
Tent temp is a constant 75-78 degrees F
I forget the name of the strains, as I destroyed the packaging. However, I do know that out of the 5 plants there are 3x different strains.

I have my next batch of seeds planted, which have sprouted in 4 days!!!! They are "Mexican Sativa" (Sensi Seeds) and "Masters At Work" from Dutch Passion Seed Company.


Thanks again for all your help and advice!!! Very much appreciated!!!


:thumb:
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016 - Photo of the Month: Nov 2020
Ok a few things, to my eye. And I don't mean to sound negative by focussing on 'problems'- because overall they look quite good and the first growing they are always going to have a few issues (and the 100th time as well...)
Just some hopefully constructive help because it's good to have plants as healthy as possible before going into flowering. When in flowering they get more fussy in some ways, and stop producing new foliage- so if you screw up the old foliage it's more of a stressful problem.

They're not as large or tall looking as I thought they might be, so no need to panic quite yet about runaway growth, hopefully.

They look somewhat spindly and light deprived. They'll need more light during flowering (and probably a different spectrum).
I don't know if you have a movement fan blowing air around in there, but one or two of those will help strengthen the stems so they're capable of carrying heavy buds.

One thing I see is some nutrient burn, the crispy leaf edges and tips. It's hard to tell how much in the plant colored by the led. But keep that in mind when feeding. The new growth looks good but sometimes when too much overfeeding has occurred the soil gets a little imbalanced from all the nutes dumped in it. Probably it would be a good idea to flush them at some point before you do go into flowering.
Some of the leaf edges are curling up. That's normally an indication that they're overheating, so there may be spots under the lights that are hotter than you think? Especially if there aren't floor fans to help with the circulation.
However, since you say that temps are good- it may be just from overfeeding, not overheating. Nutes build up in the leaves in the form of salts, leading to the same effect of drying out the leaves.

Miracle Grow may or may not be ok for cannabis. I hear different opinions. But I don't feel a lot of love when I hear the MG name. It may need some more micronutrients than are being provided. I'm not sure - haven't used the stuff.

The leaves are showing yellowing in between the veins which looks like magnesium deficiency. Often that's a (low) ph problem but sometimes plants need more magnesium, usually found bundled with calcium and called calmag. It's found in most tap water, but if you're using something like distilled water then you probably need to add calmag. Or epsom salts can be used to treat magnesium deficiency on it's own.
Having said that last part- I'm really not an expert on cannabis deficiencies and the leaf appearance might not be magnesium deficiency- it just looks that way to me. Most of my struggles involve ph. So if it seems like the nutrients are there in the bottle, and the water is good stuff, I would double check that the ph meter is accurate, just in case.

If they were my plants I would assess the situation and work on the plant strength and health over the next week or two weeks in preparation for flowering, while thinking about adding more light. If they get too tall they can be trained a bit by bending them over.

That's my 2c anyway, and like I said I'm not any sort of cannabis expert.
They're looking good and don't worry too much about everything I just mentioned . It's just nice to have them on track as much as possible before flowering, and so it's good to put in a little extra love at this point. :thumb:
 

BikerBear

Member
Thank you so much Weaselcracker!!!

I wonder if I should move them from the grow tent into the greenhouse I have in my garden.... I'm on 3 acres where no one can see. It would provide natural light and natural 18/6 light schedule. ???? The only thing is that the temperature dips to about 60 degrees at night....
 

OlderGrower

Member of the Month: Dec 2015
This may be out of left field but how often do you water your plants and how do you determine when it is time to re-water your plants. Are you allowing your pot/container to thoroughly dry out between waterings? When you water are you watering until you get run off out the bottoms of the pot/container? Do you add the water a little at a time allowing the soil to absorb the water or do you just pour it in until it comes out the bottom?

I could be mistaken but your soil looks very saturated in what little of it I can see, perhaps you just recently watered I do not know. The number one mistake most new growers do is to over water their plants, just asking because over watering can cause these kinds of issues as well.

When and how often do you feed your plants verses just straight water? What ratio of liquid MG per gallon of water are you using? I seriously do not believe your leaves were damaged by heat, if I had to take a guess with only the information available right now, I am going to say your watering them every day or your not allowing the pot/container to dry out enough which in turn has caused issues with your roots, that would explain why your plants are a little on the small side for 9 weeks.
What size pot/container are those plants in? they look like 1 gallon pots to me but that could be deceiving. To get to the root of the problem and resolve it before you flip them into flower, I would suggest you post more information. Pretty much every problem can be corrected if the right diagnosis is available and the only way to really get an accurate diagnosis is to give detailed information including things you may think are insignificant. Things like, oh yeah my grow is out in my garage and the pots sits directly on the concrete. Sounds like you did not tell me anything but you did, concrete is normally colder then the ambient air temp, and by having your pots directly in contact with the concrete your roots are cooled down, and MJ does not like having her feet chilled.
How often, if ever do you calibrate your PH meter? What size LED light are you using? What is the total amount of light you are using? How high above your plants do you run your lights?

What I am trying to get across is you have more issues then just a few burnt leaves, and the trick right now is to isolate what it is that you are doing that is not healthy for your plants so you can stop doing it that way and modify what your doing so they will be happier and healthier, which in turn will make you happier.
 

BikerBear

Member
Hi OlderGrower,

Thank you very much for your assistance!!! I think what I'll do, tomorrow, is get the girls out of the grow tent into a better area for taking proper pics.

To answer some of your questions, initially:

I water when the meter states the soil is below normal, moisture wise. I water about once per week; watering the outside edges of the containers (each about 1 gallon to 2 gallons in size) first, then moving towards the stem base. The water definitely seeps out the bottoms of the containers which I then remove from the draining trays so that the plants are not sitting in the run-off water.

I feed the plants with every-other watering; one week plain water, one week feed, alternating as such.

The LED grow lamps emit the equivalent of 100W each; there are 2x in the tent along with the daylight bulbs (5x). So, in total, I believe I have the equivalent of 1000W of light. Each of the lights are about 24" above each plant.

The greenhouse in the garden is a full-hight structure with an earth floor; not concrete. Where I'm located, it remains quite warm inside and cools down in the dark of the night (about 5 hours per night currently).


Does this help??? I'll get better pics posted tomorrow...


Thanks again... VERY much!!!


:thanks:
 

OlderGrower

Member of the Month: Dec 2015
Hi OlderGrower,

Thank you very much for your assistance!!! I think what I'll do, tomorrow, is get the girls out of the grow tent into a better area for taking proper pics.

To answer some of your questions, initially:

I water when the meter states the soil is below normal, moisture wise. I water about once per week; watering the outside edges of the containers (each about 1 gallon to 2 gallons in size) first, then moving towards the stem base. The water definitely seeps out the bottoms of the containers which I then remove from the draining trays so that the plants are not sitting in the run-off water.

I feed the plants with every-other watering; one week plain water, one week feed, alternating as such.

The LED grow lamps emit the equivalent of 100W each; there are 2x in the tent along with the daylight bulbs (5x). So, in total, I believe I have the equivalent of 1000W of light. Each of the lights are about 24" above each plant.

The greenhouse in the garden is a full-hight structure with an earth floor; not concrete. Where I'm located, it remains quite warm inside and cools down in the dark of the night (about 5 hours per night currently).


Does this help??? I'll get better pics posted tomorrow...


Thanks again... VERY much!!!


:thanks:
Yep it is a start,
so lets start breaking this down 1 step at a time.
#1-I water when the meter states the soil is below normal, moisture wise
I am assuming your referring to something like this? http://www.conservationmart.com/images/Product/medium/11429s.jpg
These are not very accurate and there are better ways to gauge when your plant is thirsty or needs to be watered. One of the easiest way for beginners is the pot lift technique. Take a pot which is the same size as the pot you have your plant in and add the same amount of soil into this pot, but do not ever water this pot, it should be completely dry.. Next you pick up the plant pot in one hand and the other pot in your other hand, when they feel like the same weight, it is time to water, if the pot with the plant feels heavier, leave her alone and check again tomorrow she is not ready for water. after a while you can get away with just picking up the pot with the plant because you will have a feel for what a dry pot should weigh when you pick it up.
#2-I water about once per week; watering the outside edges of the containers (each about 1 gallon to 2 gallons in size) first, then moving towards the stem base. The water definitely seeps out the bottoms of the containers which I then remove from the draining trays so that the plants are not sitting in the run-off water.
So if I understand you correctly your plants are in containers that are either 1 to 2 gallon in size and when you water you start on the outer edge then work your way towards the stem until you have run off, then you drain the trays. I am assuming that you are watering them with between 1 to 1.5 quarts of water before you get your run off. Might I suggest you start at the stem and work out, but do not start pouring slowly and move in a circular pattern till you get to the outside but instead, water the stem area slowly in a circular pattern then stop, allow the moisture to soak all the way in. Then work your way outward till the whole pot is thoroughly wet. Each time doing it slowly and stopping every now and then to allow the moisture the ability to get everything wet. By doing it from the stem towards the outside you are flushing out the rootball and then allowing fresh nutrients from the edges to work into the rootball. I am not very good at explaining the reasons for doing it this way but if you check out Emilya thread on "How to water your plant" it goes into great detail explaining it.
#3-The LED grow lamps emit the equivalent of 100W each; there are 2x in the tent along with the daylight bulbs (5x). So, in total, I believe I have the equivalent of 1000W of light
This one has me a little stumped, the LEDs emit the equivalent. Equivalent of what? HPS or MH? If what you are saying is like the way CFL say they are a 26 watt light but emit the equivalent of a 60 watt conventional bulb, then we are comparing apples with oranges. The whole reason a LED light is able to claim they have the equivalent to a higher HID is because some of the light produced by the HID is non-useable light that the plant does not need where as all of the light produced by the LED is consumed by the plant. So technically speaking a LED consuming say 75 watts can produce the equivalent to say 100 watts of HID. So thats 200 watts of light, I am not quite sure where the other 800 watts are coming from you are claiming. I am not familiar with daylights bulbs unless you are referring to a full spectrum lamp, which if you are is very inefficient for growing because plants do not require the full spectrum of light, only a few bands of it, which means you are creating a whole lot of light (and electric bill) that the plant can not use. My current grow I have 5 LEDs over 4 plants and am consuming 1240 watts of power, since it is LED grow lights all of the power consumed is useable power so no need to figure equivalents. I think where the confusion lies is how LEDs are marketed, by claiming they consume say 440 watts but are the equivalent of a 600 watt HPS, actually it would be more accurate if it was the other way around, a 600 watt HPS has the equivalent of a 440 watt LED since that 600 watt HPS produces roughly 440 watts of useable light and 160 watts of non-useable light. you are shooting for roughly 35 to 50 useable watts of light per square foot of grow area. You say tomato I say tomatoe

#4-Each of the lights are about 24" above each plant.
try dropping your LEDs down to 16 inches, since they are most likely only drawing around 75 to 80 watts. My MarsII 900 draws 440 watts and as Mars loves to put it, the equivalent of a 600 watt HPS and I run it between 16 to 18 inches above my plants, my small ones that only draw 150 watts are like 6 inches from my tops. Less power consumed the closer you can run them to your plants.. Oh and I would prefer my smaller LEDs were at least 12 inches from my tops but I have run out of room and have no choice but to run them that close.

While these could help you along your journey I do not believe that we have found the root of your plants condition. You mentioned you PH your water, how often do you calibrate your PH meter? You are using liquid MG but how much are you using per gallon when you feed them to the girls? Do you know what kind of medium you are using? Black Gold? FF Ocean Forest? if you do not recall is it at least a potting soil?
Sorry if this seems like a lot of mindless questions but until I know what you have done any suggestions would be nothing more then a wild guess or as I like to call it, a poke and a hope.
 

BikerBear

Member
Hi All,

As mentioned yesterday, I've attached better pictures of my girls.... Thank you ALL for the fantastic insightful assistance; it is very much appreciated.

In pictures "Plant 3B" & "Plant 3C".... are those pistils starting???

Here we go.....


Plant 1:
Plant1A2.JPG
Plant1B1.JPG



Plant 2:
Plant2A1.JPG
Plant2B.JPG



Plant 3:
Plant3A.JPG
Plant3B.JPG
Plant3C.JPG



Plant 4:
Plant4A.JPG
Plant4B.JPG



Plant 5:
Plant5A.JPG
Plant5B.JPG



Hope these latest pictures prove helpful... And, again, thank you very much!!!!


:thumb:
 
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