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Elongated, stretchy stems are the bane of any new marijuana grower. They don’t provide a stable base for a seedling, which can end up affecting the plant throughout its lifecycle. But, getting rid of the stretchy stem is really a matter of replanting the seedling, so it doesn’t continue to grow disproportionately.

Why do seedlings stretch?

There are several reasons why a marijuana plant may stretch. Sometimes there is nothing you can do to prevent a plant from creating tall stems regardless of your efforts to stop it. 

why do seedlings stretch
Why do seedlings stretch?

Many factors may cause a marijuana seedling to stretch. Some are biological and others aren’t, however in all cases, the plant grows differently as a result. Here are just a few reasons why a seedling might stretch:

  • Lack of nutrients in the soil
  • Unstable temperatures
  • Improper lighting schedule

There’s also the plant’s genetics. If a marijuana plant’s parents were originally grown indoors or if they promoted the growth of crowding plants, there is a chance that natural selection kept this trait in the seed’s genotype. But if those seeds were made by a ‘’Willy-nilly’’ crossing from hybrid plants, their offspring will be so variable that it will be hard to know what to expect. Keep in mind, some plants just naturally grow taller than others. One example of a strain that grows tall both indoors and outdoors is the tropical, landrace pure Sativa.

Tip: make sure to download my free Grow Bible for more information

Sun-hungry behavior

Marijuana plants love light, but some plants may love it a bit too much. SARP is term used among growers that is short for “shade avoidance response phenotype.’’ This is when a plant stretches to reach light that is being stolen by a neighboring plant.

Did you know that plants are perfectly aware of their surroundings?

A marijuana plant can sense when a neighboring plant is close due to less red in the light that is reflected off.  This also means they are less likely to stretch when red spectrum HPS lights are used because they have enough. Of course, temperature and the timing of the growth cycle play a role in the phenomena as well; so, the overall environment is still critical. It can decide if SARP behavior starts to show.

Factors that make your plant more likely to stretch include:

  • Space between plants
  • High temperatures
  • Not enough light
  • Distance to the light

It’s important to understand that SARP isn’t solely about access to light. It is a mixture of outside factors that interact with the light quality. The amount of light would not be as much of an issue if the plant did not feel threatened by the presence of another plant.  However, when the plant is not exposed to light for a long enough time, it becomes more sensitive to the specific red spectrums needed for growth. When the photoperiod (length of light exposure) is long enough, the spectrum is less relevant.

Stretching, that is not due to shade avoidance, on the other hand, can occur with plants that do not get enough light in terms of intensity. In an indoor setup, it could be that the lamps are too far from the plant. It is literally trying to reach the light. Even though crowding is not the issue, this type of stretching is still a problem because these plants may have a higher risk of premature flowering.

Why stem stretching is an issue

Marijuana plants can develop stretched stems when grown both indoors and outdoors. They may be easy to miss, since a stretched plant may still be large, however, the yield will be much less. Stretched plants are more expensive to grow since those long stems need extra energy – energy that could have gone to growing bigger buds.  

Indoors, these decreased yields are likely related to the challenges of creating proper lighting in an indoor grow.

Stretching can also create fragile stems, which means the plant is at risk of falling over. It is also definitely an issue where ceiling height is a concern.

Stretching can be a big problem, but there are ways to prevent it from happening.

Ways to reduce the risk of stretching

Air Circulation
Having good air circulation will allow the stems and leaves to get thicker and stronger while at the same time reducing how high it grows.

Strong air circulation can create stem and leaf movement that strengthens and widens the stem while also slowing its vertical growth. Winds will bend the stem, creating small rips in the plant’s tissue. You can also just brush the leaves to simulate the effects of air circulation.

ways to reduce risk
Ways to reduce risk

Lighting
The type of light you use also plays a role in how tall your stems will grow. Orange and red lights provoke taller, thin stems, but thick, short stems blue light is best. Using metal halide lamps while the plant is in the vegetative stage will produce short stems.

Another way to control the height of your plant is by using infrared light. You use these when the lights are off. A black cloth covers the heat lamp reflector, which makes it so the infrared rays create the right results. At the same time, it catches red light to prevent contradicting what you are trying to accomplish. It is best only to use this light during the flowering stage.

The distance of the lights from your plants can also lead to stretching. To avoid stretchy stems make sure your marijuana seedlings get enough light.

In an indoor setup, place your plants under a CFL bulb (3 watts per seedling). The distance between plant and CFL bulb should be around 2 inches. If using HPS bulbs, the distance should be around 40 inches for seedlings (20 inches for vegging plants) but make sure temperatures don’t exceed 77 ºF.

Outdoors, the distance may not be as relevant, but the amount of sunlight will be. Make sure you are growing according to your region’s growing calendar. In some cases, shorter days may cause plants to stretch – regardless of the amount of sun they are getting during the day. Even in the most tropical areas, outdoor plants may need additional nighttime lighting to prevent stretching during some seasons.

TIP: Looking to buy seeds? Visit the ILGM marijuana seed shop

Heat and Stem Growth
The temperature influences how your stems grow. The higher the temperature, the longer the stems will grow. Your plant’s stems will widen, and the growth will lessen at about 60*F. When you have it around 80*F, the stems and buds will begin stretching.

If your buds get too close to the light, this causes it to become tall and thin. Don’t make the mistake of thinking this is light burn because this is not the case. In fact, the heat from the lamps can make it unbearable for buds. Air-cooled lamps are great for keeping much of the heat from coming into the room.

Not having the proper amount of light will lead to stem stretching. As a result, the seedlings will grow tall, thin stems because it is trying to access more light. As a solution to this problem, give it a more intense light schedule, or you can place them nearer to the light. Once you have done this, the stems will grow thicker and do much better on their own.

Lastly, try pruning as a way to reduce stem stretching. By cutting off the top of the stem, it makes the rest of the branch grow.

Spacing In-between Plants
Growing your plants in bulk leads stretching. As your plant grows, the leaves may easily start coinciding with the plant next to it. Over time, this causes the bottom of the plant to be discolored, and the sub-canopy will get darker.

Reduce Stress
Stem stretching is the result of many factors, which include high/low temperatures, transplant shock, light spectrums, and humidity. Keep your plant happy by making sure the environment is the best for your plant.

Fixing Stretched Plants

If your plants have already started to stretch there are some ways to fix the problem, if you notice it early enough. If it is during the vegetative state or the first two weeks of the flowering stage, you can use blue lights to reduce it. This simple step could save a bunch of trouble later on.

Keep in mind, stretching isn’t always a bad thing. Some growers like a bit of stretch and feel that is good for avoiding bud rot in certain strains. But in most cases, stem stretching is not desirable.

Stretchy as an issue
Stretchy as an issue

If you do notice that your plant is stretching, refrain from giving it too much nitrogen. Instead, use a fertilizer ratio of (2-2-2) at the beginning of the flowering stage to keep the nitrogen levels average. Remember to keep it gradual. Making an instant shift to the normal flowering ration right after the vegetative stage causes yellowing.

Also, use oscillating fans if you’re growing indoors. A little bit of movement helps make your stems healthier.

If your plants have already experienced large amounts of stretching, here are two ways to nurse them back to life.

Bury the plant

Giving the plant a stronger base can help it stand up straight while the stems grow back stronger. You can create this base by basically re-potting the plant.

First, you’ll want to make sure the soil is dry. If it’s wet, the roots will have a tendency to cling, and you don’t want them to be damaged in any way. Then, very carefully remove the marijuana seedling from its current container. Clean off the roots so that there is no more soil attached.

You may want to use a deeper container or just dump the soil out from the seedling’s current container. Leave a little bit of soil in the bottom of whatever container you decide to use so that the roots won’t try to grow through the drain holes. Place the seedling down in the container in such a way that you can bury the stem. It is ideal to bury the stem almost completely so that only the Cotyledon leaves are showing. After that, provide the marijuana plant with just a touch of water to get it going again.

At this point, your stem will be buried, and it will eventually start to grow roots of its own. This is something that can apply to little seedlings and even incredibly long, emaciated stems. Again, as long as you’re extremely gentle with the plant, you should cause no harm, and the plant will not be stressed.

Staking

You can also reinforce your plant by using stakes. Various growers have devised methods of staking their plants so that the stems can recover.

You could use some sort of fabric, such as fabric or yarn to create a lattice around weak, stretched stems. This works especially well in a greenhouse where you can simply tie the plants so that they remain standing.

TIP: Looking to buy seeds? Visit the ILGM marijuana seed shop

Others use traditional stakes made out of plastic or bamboo and tie or tape weak plants to them for support.

If you decide to use stakes or otherwise tie your plant, be careful not to damage the stem in any way. The idea is to provide support, not stress, otherwise, the stretching will not stop. If you use stakes, it may be a good idea to invest in specialty gels that strengthen the stem during the process.

The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]

61 Comments

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  1. By Jon

    ,24 Jul 2014
    What is the difference between indoor and out door seeds? Does it really matter one way or the other?
    1. By Budzila

      ,03 Jan 2016
      BUDZILA here when is it a good time to start germination my seeds and the best-known way to due so please.
      1. By Paul

        ,19 Aug 2017
        Hey Rob my plants are 22 days old.white widow fems.there only about only 10" tall but are very health . I got them on 18 hrs. On. It worrys me does this seem normal . We do smoke mar
    2. By Snoleperd

      ,18 Aug 2017
      I have a little trick, works every time, take the paper off a bread tie so you are left with the wire, shape the wire so it's vertical stic the wire in the soil at an angle away from the […]Read More
  2. By David 1954

    ,05 Jun 2015
    Hi, Great reading well explained. Thanks.
  3. By Increase Your Marijuana Yield – 5 Tips

    ,20 Jul 2015
    […] are in their vegetative phase and are not receiving a high enough intensity of light, they will “stretch” upwards toward the source of light. This can lead to large spaces on the stem between nodes and […]
  4. By Symptom Checker – Identify Marijuana Plant Problems

    ,24 Jul 2015
    […] Stretching plants […]
  5. By Seedling Stage For Marijuana Plants

    ,18 Aug 2015
    […] Other solutions to this problem include using an excess of blue light, maintaining temperatures at around 80*F, or making sure that plants have all the light they need available to them. If light is scarce, the plants will start […]Read More
  6. By Problems That Cause Marijuana Plants To Stress

    ,18 Nov 2015
    […] You can also solve this issue by adjusting the spectrum of the light you’re using, and making sure that the temperature is hot without being overly hot. Make sure the plants are getting plenty of light, or the plant […]Read More
  7. By pat

    ,30 Dec 2015
    Can you say the reasions y one plant turnes male and the rest are fine this is at the start and the serds are femanised regards pat
  8. By Brian

    ,30 Dec 2015
    I usually use a single t5 grow light for my seedlings until they get about 5 or 6 inches tall. Is this OK? I bought a 4' 4 light t5 also for when they grow bigger then switch to a […]Read More
  9. By Stephan

    ,30 Dec 2015
    I would like to get ur bible book , not a email! I don't know if it's possible? If it is 154E County Rd 14 Cottam,Ontario,Canada N0R1B0 And I thanks u for all the help u gave me so far!!!
    1. By Jennifer ILGM

      ,03 Jan 2016
      Hi Stephan, Unfortunately the Bible is only available in as an e-book and not in hard copy.
    2. By BrianK

      ,10 Jan 2016
      just print it out and put in a binder, that might help =)
    3. By AKConiferious

      ,18 Aug 2017
      so get a printer, a 3 ring binder, and a triple hole punch...
  10. By ruven golan

    ,30 Dec 2015
    Please anyone have recommendations for supporting weak elongated stems? Is supporting by elevating the soil around the stem OK?
    1. By Jean

      ,31 Dec 2015
      @Ruven, probably not. You can do that for things like tomato seedlings, because all of those little "hairs" on the stem can turn into roots if they're covered with soil. I don't know that cannabis has that ability, and so […]Read More
      1. By Richard

        ,31 Dec 2015
        Tomatoes do produce adventitious roots almost anywhere along the stem. They aren't associated with the "hairs" you can see but the bumps that form from the base up the stem. In fact, when I transplant tomatoes, I lay the plant […]Read More
      2. By Bob Smith

        ,28 Feb 2016
        Say there Ruven: I use bamboo stakes and narrow green tape and tie them loosely. The tape is available in most grow stores. Also there is a product called "Silca" Several companies make this and it works to build stronger […]Read More
    2. By Art

      ,17 May 2016
      Tie to 3,4 or 5' stakes. Bought at any grow shop. If you need shorter stakes cut to size
    3. By Veronique

      ,20 Aug 2017
      Yes I bury them up to their necks in a larger pot mist w aloe and unsulhphered molasses
  11. By Jean

    ,31 Dec 2015
    "Not having the proper amount of light will lead to stem stretching. As a result, the seedlings will grow tall, thin stems because it is trying to access more light. As a solution to this problem, give it a more […]Read More
    1. By Lucinda

      ,31 Dec 2015
      I treat mine like tomatoes and if they stretch I bury them deeper just like a tomato plant, but only in the seedling stage. Mine always do well and have more roots because I plant them deeper to cover the […]Read More
  12. By Richard

    ,31 Dec 2015
    Robert, A quibble and a question about light: There have been two changes in the way artificial light is designated. Lumens has replace watts as we've moved away from incandescent lamps. And with the advent of tuned LED's "degrees Kelvin" […]Read More
    1. By JJ northern

      ,17 Aug 2017
      LED. for veg and flower. I say LEDs for veg. Not flower...
  13. By latewood.ILGM

    ,04 Jan 2016
    Richard, We still measure lighting in watts and lumens. What has happened is that the LED industry is so Non-Standardized, that it actually takes buying and experimenting with the different brands in order to realize at what values they function. […]Read More
    1. By Bob potter

      ,05 Jun 2017
      I just done a crop.of mazars and sugerhaze in nft under 2 marrshydro 48s cost me 82 pounds each got 12.onces of top drawer dryer cured bud best crop I be ever had this is in a 80 x 80 […]Read More
  14. By darryl

    ,05 Jan 2016
    to growers, i used led 200 watt for seedlings, but my light is about half way of my tent due to plant stretching and it works for me, once i start on my forth nod i throw them into a […]Read More
  15. By Marijuana Plants Too Hot « HempNEWS TV

    ,10 Feb 2016
    […] How To Deal With Stretching Marijuana Plants? – Stretching marijuana plants? Lack of light, wrong light spectrum or strong wind cirulation are some of the reasons marijuana seeldings stretch. To avoid your […]
  16. By Itsme

    ,29 Sep 2016
    Side by side plants in 5L pots using the same soil and sharing a 1.5m LED grow strip light. One plant shot up and the other stayed short and bushed out?? Had to raise one end of the strip light […]Read More
  17. By Eric Bowers

    ,30 Sep 2016
    The solutions only cover indoor grows. When growing outdoors, someone want to explai how to get it closer to the light? Lol. But would be great info if I was growing indoors.
  18. By latewood.ILGM

    ,03 Oct 2016
    Put it on a Large pedestal!? LOLI guess it is too bad you are not growing indoors, LOL.
    1. By Itsme

      ,18 Aug 2017
      Like your humor. I would have said ladder.
  19. By How to Increase Your Marijuana Yield – TheJointBlog

    ,27 Oct 2016
    […] are in their vegetative phase and are not receiving a high enough intensity of light, they will “stretch” upwards toward the source of light. This can lead to large spaces on the stem between nodes and […]
  20. By Darren Kirk

    ,04 Dec 2016
    Ive just stated to grow,and ive got 2little seedlings,I only have a 400w bulb so I have been putting it on for 2hours a time to heat my little cupboard then I put it off.I do this 3times a day […]Read More
  21. By latewood.ILGM

    ,05 Dec 2016
    Darren Kirk, I do not understand why you are only running light 2 houes... Light should be on 14-18 hrs per day, and off the rest. Stretching is due to plants reaching for light. Best way to prevent stretching is […]Read More
  22. By j cameron

    ,14 Jan 2017
    best compost for growing plants indoors
  23. By elizabeth

    ,22 Jul 2017
    hi Robert please will you email me i need a little advise. now as ive spoent so much money and now on second set of seeds, they ate 6 days old but thin and tall stems. i have a tent […]Read More
    1. By Roy ILGM

      ,24 Jul 2017
      Hi Elizabeth, best hop onto our support forum. Our experts there can help you with all your questions.
  24. By Tim

    ,18 Aug 2017
    I grew old Mexican weed for years. Seedy but good. The new hybrids are way better but you've got to try way harder.
  25. By Clay Scott Brown

    ,18 Aug 2017
    The plant should even out in some way... it is difficult and somehow different to use the High Powered Light on the seeds these days... considering the Hydroponic Arena where vast farms of it are grown with Amazing Root and […]Read More
  26. By Davoid

    ,18 Aug 2017
    What time of the day is best to feed my outdoor plants?
    1. By latewood_ILGM

      ,18 Aug 2017
      David, You always feed your outdoor plants as soon as the Sun comes up. :)
  27. By It’s me

    ,18 Aug 2017
    I started an indoor grow with 40 plants. They took off like bottle rockets, grew 10cm in a couple days - really tall and skinny then started falling over even tho I had a fan blowing on them and white […]Read More
    1. By latewood_ILGM

      ,18 Aug 2017
      It's me, Seedlings stretch out due to inadequate light. Invest in some T5 lighting and keep it 2" above your babies. I think you will like the result.
  28. By russ hochman

    ,11 Feb 2018
    hello everybody----- i,ve done my re-search & still the same :-( streaching-stem,s under 1,600 lum,s of cfl, & happy-frog, ( the best of both-world,s ) ( from lite,n,soil ) whats a worried-man to do, im russ, i know-i know, but […]Read More
    1. By latewood_ILGM

      ,16 Feb 2018
      russ hochman, First thing to do is lose the CFL. Invest in a 4 tube T5 lamp and put it 1.5" from the sprout and monitor and adjust as needed to keep lamp 1-2" from seedlings. This will stack the […]Read More
  29. By latewood_ILGM

    ,16 Feb 2018
    russ hochman, BTW, 1600 lumens is very little.
  30. By russ hochman

    ,22 Feb 2018
    latewood_ilgm, ----im on a buget, cfl is all that is around & cheap, you didnt say anything about my soil, so im guessing frog-dirt is good, steem,s are wiked-turn,s & 2nd & 3rd leaves comeing but awfull steem,s, im lost […]Read More
  31. By latewood_ILGM

    ,27 Feb 2018
    Join here!: support.ilovegrowingmarijuana.com Leaving a Red light on 24/7 is totally off base. I suggest you take me up on my offer and join our forum. It sounds like you are loving them to death ;) Happy frog is OK […]Read More
  32. By russ hochman

    ,28 Feb 2018
    allwrighty-then & 10-4 gottcha-ya
    1. By latewood_ILGM

      ,18 Apr 2018
      Russ, I hope to see you in the forum. Perhaps you already got help. There are so many options for you that it is hard to discuss it all here in the blog. IN the forum; When you post; Place […]Read More
  33. By Tombstone

    ,15 Sep 2018
    New at this. In the 70,so it was easy. First grow and all 5 stretch Ed and baby sitting the last one using the tips here. My question is my next order, what strain is best for THC for extreme […]Read More
  34. By latewood_ILGM

    ,25 Sep 2018
    Tombstone, I recommend you try Robert's Gold Leaf. This is out signature strain, high in THC and CBD. An excellent grower with good yield and a favorite among members at ILGM :) Happy growing
  35. By Edward

    ,11 Feb 2019
    Thank you for the response. This is actually my third grow. I was just wondering if this common for the strain. Blackberry Kush. I actually have nine plants going out of the ten seeds that I germinated. Not too bad

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