420 Magazine Background

Why do my seedlings stretch?

SmokeyMacPot

New Member
Seedlings stretch due to the influence various factors. In other words the way the genotype is expressed is determined by the biotic and abiotic factors affecting its growth. The site where the plants are grown may be conducive to stretching due to a nutrient deficiency or other factors like temperature or day length.

The source of the seed is also important. If the environment that the plants were from originally was consistant from year to year (for instance, indoors) and/or encouraged stretchy plants (crowding), natural selection may have passed on the trait for stretchy plants. If the seeds were from hybrid plants that were crossed "Willy-nilly" the variation of the offspring will blur the distiction of phenotypes.

When plants stretch due to competition for light, this is known as the "shade avoidance response phenotype" (SARP). The light reflected off of other plants has less red in it because the leaves of the other plants absorbed it already. This is how the plant knows how close it is to its neighbors. When there is less red, the plant stretches so it can compete better for the light. HPS lights are high in red spectrum, so plants grown under them stretch less.

Plants match their phenotype with the environment, but this can depend on other factors. Temperature and photoperiod can affect the response to red light by limiting which phenotypes are expressed. Higher temperatures, shorter photoperiods and dense planting make the plant more sensitive in its response to the amount of red.

The SARP is really an interaction between abiotic factors and the quality of light. The size of a plant that has stretched may be larger than a plant grown under a full spectrum, but overall yield will be less. A plant grown under a short photoperiod is more sensitive to red, but a plant with a long photoperiod period will stretch regardless of the spectrum because it has time to make a longer stem. In fact under longer photoperiods, the plants become less sensitive to red because seedling elongation affects the health of the adult plant.

The seedling is aware of it surroundings. The SARP isn't affected by photoperiod in a seedling because the seedling has to be aware of the density of the population, but if the day-length is short enough to induce flowering, then they will stretch. An elongated plant costs more to grow because your growing more stem and less bud. So under conditions of dense planting the temp and the photoperiod determne how close to plant to minimize stretching.

Authors: MR_NATURAL420
 

MrsLonely

New Member
Is there a way to stunt the stretching of the seedling? Mine seemd a lil 2 tall already.
 

MJGenius

New Member
Hey MrsLonely, the only way I know how to stunt vertical growth in seedlings is by moving your lights closer. If you cant do that, move the seedlings closer to the lights. If your using HPS' then i wouldnt suggest doing that as they emit waaay too much heat to be that close to the actual plant. Hope this helps
 

braynes

New Member
How far away should they be if I am using a 400watt m.h. light. my seedlings sprouted 2 days ago?
I do not think you should use a 400mh light that soon,you can not get in close enough to not prevent stretch.
br
 

bullisok

New Member
After seedling gets to about 6-8 inches and looks more like a plant not seedling I FIM the Top and it slows the up growth and cause the side branches to grow... I usually wait longer then that but if I have a plant stretching too much it works for me to slow it down and let the rest catch up.
 

rattlerr

Member
Plants normally stretch when they are reaching for the light, from what i have read and studied. You should keep the light between 1 foot to 18 inches above the plant depending on ventilation to move heat.

I have 96,000 Lumen of Sun Blaze T5 HO and keep my lights 14 inches above my plants. I also have my plants receiving light from 4 sides "Top,Back,Left & Right" leaving the front open for work and air movement.
 

68camaro

New Member
bend it to slow the streachin, easy does it though no stress and you shouldnt be able to tell you bent them at the end of the day. it will blow your mind i guarantee you!!! bend it dont top it!!!! it does all kinds of things!!!!
peace
68
 

QUEENBUD00

New Member
them plants,when grouped together stretch to get more light the bigger ones take what they want..you either give them more light or rearange them.....or put them girls outdoors...
 

superfly

New Member
ok i have a ?, why hasent anyone done a discution on watering as a seedling, my first seed poped threw the soil and im not sure how much or when to water it, running CFL's got light about a foot or so from plant it jumped threw the soil 2 days ago, im not sure how much water to give it at this young an age eather, any help would be awesome
:adore::adore::adore::popcorn::adore::adore::adore:
 

Captain Kronic

Member of the Month: July 2011
First off... welcome to 420 mag forums, roll one up and chill!

Secondly, if you look, there are many thread and articles here that cover that exact thing and more!
Here is a thread that is directly above this one!
How to Grow Marijuana - 420 Magazine

EG:
Germination & Techniques
How Do I Germinate Seeds?
Preparing Seeds for Easier Germination
Is There a Faster way to Germinate Seeds? (Scarification)
How Do I Germinate Seeds in Soil?
What is an Idiot Proof Way to Germinate Seeds?

Germinating Cannabis Seeds (for Bio Growers)
Vapour's Rockwool Germination Technique
Vegemite's Seed Germination Technique (Rockwool)
KiDKiND's Germination Technique
Joe's Seed Germination Technique (Rockwool)
How Do I use Oxy-Plus for Seed Germination?
The Germination Process of a Dicot Seed
Soil Germination Problems
When I am tending seedlings, I usually check them twice a day. You should be able to tell what they need, by the look of the soil and also by the weight of the container you are using... test this by watering them sufficiently, till water dribbles through and then pick it up, you should have a pretty good idea when they need more H20.

Chances are if you temps and or air flow are right, you may need to water daily... I do!

Also, if you are using a nute free soil... once they get into veg, a couple sets of true leaves, give them a diluted flowering nute to promote root growth!
 

superfly

New Member
i am using soil that you get at walmart for cattis type plants. crosses fingers thats good i hope, im still really new at this whole thing i just wasent sure with the seedlings i have been on here almost daily to read up on stuff. for my seedlings i am useing a plastic cup with soil the seedling is sticking out about an inch or so, i just have been giving it a little water here and there, when i feel it and it feels to dry to me, my 1 CFL is about a foot or maybe a little more away from it, i am using my closit it has a nice air flow, it seems kinda cool in there, but under the light it is very worm, getting more lights in a few days, useing 100 watt light bulb:lot-o-toke::high-five: :thanks:
 
Last edited:

voltron

New Member
i am using soil that you get at walmart for cattis type plants. crosses fingers thats good i hope, im still really new at this whole thing i just wasent sure with the seedlings i have been on here almost daily to read up on stuff. for my seedlings i am useing a plastic cup with soil the seedling is sticking out about an inch or so, i just have been giving it a little water here and there, when i feel it and it feels to dry to me, my 1 CFL is about a foot or maybe a little more away from it, i am using my closit it has a nice air flow, it seems kinda cool in there, but under the light it is very worm, getting more lights in a few days, useing 100 watt light bulb:lot-o-toke::high-five: :thanks:
If you are using compact flourescent lights (cfls) you should have your lights as close to the plants as possible so as not to burn them. You should be able to get the cfl depending on watts to at least 2" away from plant without burning them. Mh/HPS may have to be 12-18" away to prevent burning your plants, especially if you are not running a cool tube or have some other exhaust/duct attached to the reflector/bulb to draw heat away from bulb up and out of tent.
 

jessiijess

New Member
Im a first time grower and am pretty much learning as i go. I was given an 150w hsp light to start germination. Is that the right light to use? Also my plants are slightly leaning and are lookin kinda weak. Any suggestions? Theyre about a week and a half old:cheer:
 

mkKush88

New Member
I am using a super lcoker to grow in i am doing a test run with 1 plant but it seems to not be growing as fast as what everyone says it should, and it looks stretched to me any sugestions?
 
Top Bottom