New Grower How to Slow Vertical Growth?

[Vassternich]

Hello all, my first grow was four plants this spring and it was rocky but produced some nice stuff in the end at about 2.5-3oz per plant. I used crappy pots from Walmart, Fox Farms Light Warrior but PH'd it like soil instead of hydro,looked like dirt to me ,and didn't over-water enough which probably caused bad mineral build up. The tallest plant at the very end was about 23".

So, now I am on round two of four plants in a 3x3x6 tent but with new Superroots air pots and a coco mix from a local shop that came in large bags which I am PH'ing like hydro. The issue, which I am guessing wouldn't normally be an issue for someone with a bigger tent, is that the things are growing like mad... Three out of four are at about five weeks since sprout, the other was behind two weeks because the original died during sprout. The fan leaves are bigger than my hands.The three older ones are approaching 4' tall plus the 1' pots and filling up the tent from side to side with leaves folding on all edges, the things grew over a foot in the last five days! They still have no buds on them yet but are all female autos. My light is almost to the top of the tent now and the 400w HPS(I just switched from the 250MH last night to lift it up and get more light to the bottom) is about 6" off the top of the tallest one.

Questions:

1. Do I need to worry about the leaves hitting the sides of the tent and the bottoms not getting much light because of the canopy?

2. Is there a good way at this point to stop them from growing taller without hurting them?

Thanks much for any info.

 

[zain123]

firstly...u should have lstd...u can start now as its never too late... (unless the branch is hard and thick then u cant do squat)

secondly...add a few cfls for those areas u see that r shaded. They wont contribute much to the heat and will give u the light u require so u dont end up with popcorn buds.

 

[Vassternich]

Thanks, I had heard of LST/SCRoG type of growing but didn't know it applied to autos also because of their short life and temperament. After some quick research on your suggestion I should be able to tie the tops down to the pot next to it in some sort of pinwheel design to lower them a foot. The stalk is still bright green and should bend that far. I can't really do too much because i need to pull the pots out to water them but I think that will help quite a bit. I think next time I will make a drain system in the bottom so I don't need to move them and LST from the beginning or switch to just one plant in a screen with how big these get compared to the 4 from a variety pack I had last time.

 

[Muddy]

At 5 weeks you could still have another week of veg growth to go. We normally don't recommend making the switch from veg to bloom nutrients until vertical growth stops, but you may want to make the switch sooner to help slow them down. LST is the best option. How does your node spacing look? Is it more than an inch or so between nodes?

 

[Grey Bear]

To slow the growth of any branch that is looking like it is going to get too high-

Squeeze the branch between your thumb and index finger about an inch from the top.

The object is to squeeze the fibers just a bit, not crush the hell out of it.
It should be "almost" droopy where you squeezed.

This will slow upward growth of that branch, but not overly stress the plant.

It can be repeated as necessary, just try it with a few branches for a couple of grows before you go overboard.

 

[Trapper]

Fimming ^ ^ ^

It worked for me when arresting the vertical growth of My Sati-dom Dark Devil....and it produced a Tri-Top bud

The best way I can describe how it feels...squeeze until it "gives a little" or "pops", but without vertically splitting the outside of the stalk.

 

[Vassternich]

Thanks for the suggestions, I am not sure on the node spacing but will check it out when i get home. I know they are much further apart than my last grow(twice as tall though too) even though I kept the light close to the plants, I had to keep moving the light up every couple days because they would grow right into the MH fixture. They don't have any light damage probably because the bulb was only a 250w. Now it is a 400 HPS so I want them to stay back a little.

They are due for food tonight so I will try switching to bloom nutes and attempt the squeezing idea on the tallest one that just wont stop growing. I was going to try the LST but they are not as flexible as I thought, the bottom of the main stalk is more like a trunk, about 3/4" diameter with a sort of bark forming. The others have slowed down now but this one is a little out of control, maybe I shouldn't have used the five gallon equivalent air pots and went with half that size. Next time I am thinking maybe just one-two plants instead of four and try out LST with a screen for this tent size.

 

[Vassternich]

From what I understand the node spacing is the length along the main stalk where sections of branches grow outward....I think. If this is the case the nodes are between 3-5" on the one over 4', the medium ones are 2-4" and about 3.5' tall, the smaller younger one is about 18" and the nodes are about 1-2". The taller one has side branches coming off that are 2' long but stand up on their own. It has some small buds now forming all over the place and I switched to bloom nutes like suggested. I will try out the stalk squishing method as suggested also when I go to put them back in their cage.

If you guys think the node length is wonky maybe I need a stronger light or something. When they were little babies at like 4" tall I had the light about 18" away and didn't move it until they got within ~6", then kept it within 12" as they grew. It was a 250w MH bulb. Or maybe this plant is just way different than my other only other grow, it is Strain Hunters Damnesia Auto.

Thanks again for the advice all.

 

[Dr Fluff]

Keeping light period temps the same as dark period temps. The greater the temperature difference between light period and dark period the greater the stretch.
Dark period temps can be kept the same as light period temps by adding a tube heater or equivalent and using a thermostatic plug socket available on ebay for about £17

Here's what Ed Rosenthal has to say on the subject

Temperature, Humidity & Air Quality
Marijuana grows well in moderate temperatures – between 70° and 85° F (21°-29° C).

Both high and low temperatures slow marijuana’s rate of metabolism and growth.

Plants grow fastest when the temperature during the lighted period is kept between 72° and 77° F (22°-26° C). When CO2 is being used, the plant prefers to be a few degrees warmer, between 79° and 85° F (26°-29° C).

Individual marijuana varieties differ in their temperature preferences by a few degrees, so some experimentation is required to find the ideal temperatures for the strain you are growing.

Ideal temperature is tied to light conditions.

As more light is available, the ideal temperature for normal plant growth increases.

Strong light and low temperatures slow growth and decrease stem elongation.

Conversely, when plants are given high temperatures and only moderate light, the stems elongate.

Plants growing under moderate intensity lamps (40-50 watts per sq ft, 430-540 watt per sq m) should be kept on the low side of the recommended temperature range.

Plants growing under higher intensity lamps (60 watts per sq ft, 650 watts per sq m and higher) should be kept on the warmer end of the scale.

During dark periods, the temperature can be kept as much as 10˚ F (-12˚ C) cooler than the lit period without any negative effects. Wider temperature differences cause slower growth, stem elongation and delayed flower ripening.

Plants that are kept at a constant temperature are likely to grow stouter, sturdier stems and have denser bud growth.

Plants that experience a large differential between day and night temperatures suffer from stretching and slowed growth rates.

At temperatures below 60° F (15° C), photosynthesis and plant metabolism slow, stopping growth as it waits for better conditions.

As soon as the temperature rises, the plant resumes full functioning. When the temperature falls below 40° F (4° C), marijuana plants experience tissue damage and require about 24 hours of warmer conditions to resume growth.

Young marijuana plants are somewhat tolerant of low temperatures; when outdoors, seedlings have been known to pierce snow cover without ill effect. But low temperatures during ripening, even just overnight, delay or prevent bud maturation.

Some equatorial varieties stop growth after a few nights with temperatures below 40° F (4° C).

 

[Vassternich]

Thanks for the info Arty, I decided to veg these at 24/0 light schedule and the temp was pretty consistent at 73-74* but that is still a good thing to keep in mind. I have switched to 20/4 for bloom because the bulb is 400w compared to 250w and I figured I wouldn't gain much using the extra four hours of power.