autofloer seedlingWhat is a seedling?

A seedling is a young plant or rather that plants growth stage. This growth stage is every naturally grown plants first life cycle and it is also the most fragile and the most dangerous of them all.

In general their life cycle starts when the seed cracks open and ends as soon as the first true leafs appear. Basically a seedling is a plant embryo that sits in a protective layer (the SEED Shell) and start growing when moisture penetrates that protective player. After that initial seed cracking that young plant tries to find sunlight by growing upside down from where the gravity is pulling the seed. This happens because seeds are usually found under ground or under leafs or other material and to get light and in that sense power to grow this plant tries to find its way upward. Seedling at this point grows completely on the power that is stored in the seed because it is not photosynthesizing yet and so there is no energy production. When that little plant reaches trough the ground and finds light the process of leaf opening is started. As soon as those seed-leafs are opened the plant starts photosynthesizing and its true life has started!

How autoflower seedlings differ from other plants?

Autoflower seedlings just like regular cannabis and other plant seedlings have those seed-leafs and cannabis plants differ from other plants like grass and pine species because they have two seed-leafs (dicotyledons). These seed leafs are usually a bit bigger than other specie seed-leafs and if you have seen a lot of plant seedlings you can distinguish cannabis youngsters from other plants. But in general they look like any other seedling and up till the first or second true leafs appear there is little evidence that this young plants is actually from the cannabis genus.

How the growth differs from later growth stages?

Cannabis at this growth stage grows slowly and focuses most of the energy to root growth in order to cover more ground in search for nutrients and also to stabilize itself in the ground. Basically anything that this young plant does is there because it is programmed to survive and that is why you should be careful not to damage this delicate plant. At this start growth stage cannabis plants don’t use almost any nutrients from the surrounding environment and use up all the elements that were present in that seed when it was formed.

autofloer seedling close upNutrients, watering, humidity, light and temperature?

because Seedlings use elements from the seed itself you don’t have to give any added nutrients to your growing environment and give them plain water. The watering should be regular but they must not dampen the growing medium too much as too wet (soggy) growing environment increases mold and other bacteria risk but in general you must water more frequent at this stage of growth but also give relatively small amount of water. I like to water my seedling with a hand held humidifier because this allows me to not only water the ground but also moisten that young plant itself and that is convenient because those youngsters need somewhere from 60 to 80 % humidity to flourish!

Cannabis seedlings can grow in almost any light schedule but light schedule as well as intensity and color can affect how fast you seedling develops. I usually keep my seedling under fluorescent lights that run 24/7 as I have found out this increases the growth a bit. In general it is really hard to measure any actual changes in plants if you give them 1 hour less light or keep them in a bit colder than average room only while they are at their seedling phase but thinking about the factors that are involved in that young plants growth we can deduct that:

  • Seedling need warm temperature (29 or above C) – This is because cannabis seeds in nature sprout in the spring when the temperatures are warm and the plant can properly photosynthesize.
  • Seedling need 24 hour light period – Young plants need as much light as they can get and that will help them develop faster and give you bigger end yield!
  • They need very humid environment (60%-80%)– seedling germinate in damp environments and for the first few days they need to retain that wet environment to not dry out and to be able to kick start their life.
  • Seedling need no outside nutrients!
  • They need 6.5 to 7.5 PH plain water!

Because seedling phase is the first one any errors or environmental troubles can greatly impact the end yield as if you lose just one growth day at the seedling phase you can in fact lose a lot of growth because when the leafs and plant are small they can’t gather a lot of energy and for every energy unit gathered trough photosynthesis that plant grows the same unit of cells!
So when we make some fictional calculations we can see the difference!
Imagine that each cell that can photosynthesize can produce 1 unit of energy and a new cell needs 60 units of energy to develop and all new cells grow at the end of the day and also every minute one cell produces this one unit of energy. In this experiment it means that every hour of light can produce one new cell from one cell.
Let’s start with one cell and two light cycles 24 hours and 12 hours:
24 Hours-

  • 1. day – 1*24*1 = 24
  • 2. day – 24*24*1 = 576
  • 3. day – 3456*24*1 = 13824
  • – 13824*24*1 = 331776
  • – 331776*24*1 = 7962624

12 Hours-

  • 1. day – 1*12*1 = 12
  • 2. day – 12*12*1 = 144
  • 3. day – 144*12*1 = 1728
  • – 1728*12*1 = 20736
  • – 20736*12*1 = 248832

And at this, my make shift experiment, the difference between the 12 and 24 hour light cycle is significant and the 12 hours cell count is just 0.3 % from the 24 hour cycle cell count!!!
This experiment is in no way scientifically correct but is just a way to show how much better it is for a seedling to get more light and you must provide the best environmental conditions that you can or your total yield can greatly diminish.

humidity dome

Humidity Dome?

A humidity dome is a device that lets you increase the humidity of a particular area of your grow room by enclosing it in see-trough plastic and not letting in any outside air. These domes help with humidity and also temperature control and not many growers use them for seedlings but they should, because, in them you can easily increase or decrease that humidity percentage, and you just have a greater overall control of that grow environment!

In the end I must admit that seedling phase in any plants life is important and it is specially important in cannabis plants because every gram of those end buds is so valuable and it doesn’t matter if you grow short-day cannabis plants or autoflowers, you need to treat them equally!


  1. BayLee420 on

    Just started 2 Nothern Light and 2 Short Rider Autos. Although I’ve started countless seeds. This thread was a nice read. I’m an Old-Timer when it comes to growing. K.I.S.S is my way of doing things. Your thread is just what I’ve done for years. It was good to read that my growing method is what we need to do.


    • Hi, Nice to hear that you are doing the same think as I am,
      Maybe you have some other good tips to this blogs readers?

      • Do I add nutrients in week 8 with auto flowers? How much water should I be giving them?

  2. Anth parry on

    One of my seedlings got uprooted for a few seconds and leaf is strange shape will normal leaf come next

    • if that seedling lives it should be ok and strange deformation on those first seed-leafs are normal. Just wait for those first true leafs to form!

      • Anth parry on

        My seedling is ten days old and is a little behind will it live if its still going now its a little slower will it b ok to go under 250 hps then turn up to four and then six hun watt thanks midowo

        • I think it will be ok, and that plant will just grow a little slower and produce little less overall yield.
          As for the lights, HPS have always been the golden standard of cannabis growing so they should do great!

      • Colin Asa Wescott on

        I started a Crop King blueberry x big devil last week , instead of 2 small leafs coming out of the top it has 3 , pretty cool looking , anxious to see how it grows out in the next couple weeks

  3. i have read that in outos alot of people drop the light times for the last couple of weeks, i was just going to run mine 18/6 start to finnish,what do you think is the best way to go,i have only a few weeks left 4 at most for one of them so dont want to do the wrong thing now,,,,,cheers

  4. On my 6th week growing WW auto.Growing in FF Ocean Forest soil.Was doing beautiful until it started to flower.many small buds with droopy leaves and slow growth.Havn’t givin any nute’s yet.Could that be problem?

    • nutes could be the problem with the size, but at 6 weeks it is normal for an autoflower to start it’s flowering life cycle!

  5. I am growing an auto flower for the first time. Do they get pinched back like regular seeds or is that something the plant does on it’s own?????

    • Hi CJ420,
      Tnx for the question!
      In my experience autoflowers don’t like to be messed with and pinching, topping and other High Stress straining methods will decrease the total yield because these plants have a set lifespan and if you stress them they will have less time to grow and develop those buds!

  6. Needtoknowautos on

    I have just germinated 6 lil girls, 2 candy kush, 2 chemdogs, and two thc bombs, all autos. After they germinated in 48 hours I then put them into their final pots approximately a quarter inch below the surface and covered with a bit of soil. My temp and humidity are in the ideal range. It’s been two days now and I still haven’t seen anything poke out. What is the time frame or a seedling to sprout above ground?

    • Hi there!
      They can srout anywhere from a few days to a week from the first touch with moisture.
      Hope they have already began their life cycle!

  7. Needtoknowautos on

    And it’s began! They are under way and life is great. Although my two candy kush’s never made it for whatever reason, the others are big and beautiful! I just added their first dose of nutes and I’m afraid I might be seeing a burn soon. My recommend dosage on the bottle says 15ml/gal, and I added 4ml to two liters. I had a major brain fart and didn’t do my math correctly. My mute schedule should roughly be a quarter of the recommended dosage correct? Ur site is absolutely awesome! I talk to the boys on AFN about everyday, but all in all ur site seems to be what I revert back to whenever I’m searching for answerS

    • Tnx for the kind words, but yes 1/4 is the recomended dose at the start, hope your plants will survive!

  8. superstacks on

    Hello… newbie on your site/forum, however, on my 3rd round of germinating from seed/growing plants. First two rounds, sativas and i did remarkably well (i think). Harvested both rounds and although i had some issues, the outcome was a success. 🙂 so instead of those stretchy buggers….i have now invested in autos. as of this am…. i’ve got 3 seeds in pots…waiting to see that lovely little sprout! MDSS….Limited Edition – Sour Spyder. I am so very excited about not having to worry about a light schedule!!! your site has been very informative and i’m glad to be a part of it!

    • Tnx for the comment!
      I have not grown that strain, so it would be great if you could provide some information about it after your grow!
      Good to know that people are still choosing autoflowers not regular photo-sensitive Sativas and Indicas.
      Hope everything goes great with your grow!

  9. Malayan420 on

    Hi. I am a first time auto grower. Thank you very much for your tips.
    My 4 week old Auto Blue seedling is sick. The first set of single fingered leaves turned yellow and all crinkled up, its stem is skinny compared to my other 4 week old seedling. These are all caused by grower’s error. I wanted to start over but my sick Auto Blue seedling is VERY SLOWLY growing new sets of leaves. The new sets of leaves looks a bit deformed. Will it survive or should I just re start?

    • If you have more seeds I would suggest to try again because even if this plant survives it won’t give you big yield!

  10. So I just planted a dwarf lowryder auto flower and it’s been 7 days now and the seedling looks like it was when it popped out of the ground just a tiny bit bigger with 2 little leaves beginning to pop out ,I started it in a 3 L pot but it seems. To be going very slow if it’s going to be flowering in 2 weeks

    • In those first days your plant is growing more below ground creating that root mass that will allow a much faster above ground growth. I thing it should be just fine and you just have to monitos those enviromental connditions. That growth speed will increase almoust exponentially and you will see a faster and faster growth.

      If you don’t see some new leaves forming in about 3 to 5 days then you can start to worry but I thing everywthing will be just fine.

  11. Temp is at 27′ and humidity is at 53 lights are t5s 2 promix potting soil with 1/3 perlite

      • I’m confused Tanner says he’s 27c and RH 53 ! Thought the humidity is also supposed to be 70 ,to 80 read were they like high humidity in seedlin stage. 3 days young ???? TY. In advance for reply

  12. 2 small leaves have appeared over the rounder leaves very small rounder leaves are turning yellow around the tips and the first pointy seedling leafs are like a dark green

    • It sounds like a nutrient, overwatering or PH problem.
      What is your PH level and how much did you water your little seedling?

      • Oh it is between 6.0 and 7.0 idk how to measure the ph in the soil and I’ve watered it once with like 250 ml of water and I’ve been misting it because the first inch or two have been close to dry on the moisture meter

          • From the information that you provided everything starting from the enviromental connditions to soil and PH seems to be just right.
            Maybe it is just a weak seed with some “not-so good” genetics?
            In my opinion if your little seedlig does not recover in a couple of days then discard it and start over with a fresh seed.

  13. I have three out of four Trans Siberian seedling they have been above ground 15 days and are only a inch of two tall. They look like miniture pot plants, don’t seem to be getting taller. Am I expecting too much right now. I am afraid I will love them to death. Nutes now or just water every other day?

    • What soil are you using?

      15 days are not a long time but by now they should have those first true fan leafs and in the coming days there should be a rapid grow happening. In the first week or two those plant usually create a massive root mass and then the above ground growth starts.

  14. Thanks for the reply, they are showing some signs of starting growth, 1/2 inch a day. I will start on nutes next week and see what happens.
    I had them under a MH light and have moved them to a 8 light T-5 and they are doing better. Plan on moving back to HPS in several weeks. Sound right?

    Kindesr Regards, Dave

    • Great to hear that.

      Yes, T5 lights are great for vegetative growth but for flowering it would be best to move them under a HPS light source.

  15. Good Morning

    this site is so informative How long after Germination does the leaves pop out of soil on ave. I am a Newbie and probably being impatient just looking for ave sprout time. only been 4 days Thanks again

    • Tnx man!

      Depending on how deep did you plant that seed it can be 1 to 5 days. The fastest I have seen a seed sprout is in just a couple of hours but I think the longest was 4 or 5 days.

      • we have seedlings lol 3 popped normal 2 grew upside down very strange but all seem to be strong now. I also went 1 2700 and 1 6400 bulb for full spectrum full monitor of ph temp and humidity is good would like humidity a little higher right at 62 but so far so good I will keep you updated as we progress

  16. sick to my stomach RULE #1 DO NOT OVERWATER YOUR SEEDLING damping on 3 out of 5 someone thought they needed water and out of no where the dreaded top laid over Fuck me guess I am starting from scratch again Live and Learn

  17. Hi. I have an auto flowering skunk. She is entering week 3 of flowering and since seed she has a total of 8 weeks, so 5 of vegetative and 3 of flowering. It looks beautiful and its about 1m tall. However it keeps just growing hairs after hairs but hasn’t really showed that boom and start forming buds. Can autos grow over 3 months?? Or should I be concerned?

    Thanks a lot!!

    • Hi Nuno,
      Super autoflower strains absolutely can grow longer than 3 months.
      It sounds like your strain is a super-auto plant and those can grow for more than 5 months and get up to 2 meters in height.

      Just keep at it and soon you will see those buds forming!

  18. Hi there, hope to get an answer to a problem although I think know the problem and overwater springs to mind, however, I planted my auto mazar sraight into there final pots, started them on 250w now on 400w and am gonna be going upto 600w, my seedlings are nearly6weeks, there first leafs are dead, crispy, other second leafs are just about dead, but new growth seems alright, the other I much more bushy, more healthy, thicker stem, but I’ve gt reading stems, and crispy leafs, first n second lot yellow also, I’ve stopped giving canna start, forgot that a load of nutes would be in my medium and there in 11ltr pots, please help, new growth on another is light green, they only 6weeks, is it over water, thanks so much!

    • That sound like a nute burn or overwatering. I would advise to stop giving your plants nutrients right away and maybe water them less frequently.

  19. my seed leafs have popped out and been out for almost three weeks but no others leaves have grown it looks nice green and healthy though does this mean something could be wrong or am i just being impatient

    • Three weeks is a long time for a plant to not develop any new growth. What is your soil and what strain are you growing?
      In all honesty – that sounds like a stunted plant, but it may well be a really slow growing strain.

  20. wildbill on

    I have three feminized auto seedlings going right now. Each is about 2.5 inches tall at the moment. they are on a 24 hour cycle at the moment. I was wondering when I should start giving them nutes (cannas terra vega) high in nitrogen and when i should switch to something higher in phosphorous (terre flores). Also I am currently running 100w CFL over each plant will this be enough light?

  21. How long is the veg stage for an auto?
    For example: if I done big bang, which is 39-45 days flowering then how long would it take all together?

  22. I have set up some autos and one of my seedlings seed leafs has died, will the plant survive?

  23. Hey man great info appreciate it all. I am a first time green house father of six auto fem super silver haze. Thanks to this article and thread I am realizing that super in the name has a greater meaning then Initially thought. As of yet I have done all natural as just putting the seeds in the soil. After 5 days I have an inch tall beginners. Well now that I’m realizing I have supers I am feeling that all the info I have acquired this far may be irrelevant to what I actually have and how long it’s going to grow. For starters when should I start using nutrients and how often should I water. If anyone would like to take the time to have a conversation with me more personally that would be greatly appreciated. I have had alot of trouble finding specific greenhouse instructions for autos and now specially since I have supers.

  24. I have planted two autos 14 days ago, White Widow and Blueberry. They both have the first true leaves about 1/2 inch and have the second set coming. Are they supposed to be this small at this point?

  25. Hi. I’m a newbie completely outside. Australia bound. All my seedlings successful except one. The One of my seedlings alot taller than the rest an sprouted new tiny white leaves last week at the top of the seedling that have not progressed an tips have turned a muddy brown colour barely.
    Lower two levels sprouted 4 sets new and healthy green leaves. I’m guessing a deficiency can’t figure which one.
    I repotted this morning an am wondering do I leave it in the sunlight? In the shade for a few days? What do I do guys

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