How to prevent seedling stretch after germination?

[TREE KING]

hoosierdaddy, i take from your answer that 5 inches from the plants would never be too much light for seedlings. thats my main concern. i understand about the heat. thanks for your help.

 

[queg]

I've had this problem as well... I use plastic wire twist ties to support them until hardened off, then just bury them deeper when transplanting.

 

[hoosierdaddy]

TK, there is no way we can mimic the intensity of the light the sun puts out.
If you can keep the temps acceptable, you can get any light made as close as you want.
Flouros are not too intense in any shape, form, or fashion.

 

[dontstepongrass]

i use a similar t5 system and it gets rather warm. make sure your ventilation is top notch! also, i use mine for flowering as humidity drops to under 30% with all that heat. a humidifier might work for you then again i dont even know your climate

 

[TREE KING]

its gonna be in a huge wide open area so i dont think the heat will be a problem. thanks everyone

 

[FreezerBoy]

No rap against Rapid Rooters but, Rockwool is perfect for germing and cloning. Domes do more harm than good. I routinely clone in 15% humidity without one. I use one for germing only to keep the cube moist until sprouting. Once a plant sprouts get it out of the dome ASAP. If you have to use one, acclimate plants to the outside air slowly.

80 + degree temps will definitely cause stretch. Try watertemps of 72-75. 18 inches sounds a bit far. I realise I'm using a 250 compared to your 400 but neither of these have anything on the sun which is used for germing all the time. Our concern is in baking the plant from heat proximity. Cool the cab and drop the lights.

You can always bury the plant deeper when you transplant to larger cubes or netpots. This will stall the plant a week or two as it grows new roots at the surface but, will turn your 6 inch seedling into a 1 incher.

 

[Guest]

what i do is put my seedlings in the red beer cups with holes in the bottom.and when the
seedlings start to stretch i fill the soil mix and by the time its up around the top it starts to get stronger as i lower my 250watt and they grow fine .

 

[split kooks]

super informative thread

 

[Azeotrope]

I agree with FreezerBoy, at this point you should move forward and plant them right up to the first set of leaves.

 

[NorCalFor20]

To whoever asked: I started my seedlings under fluros until they developed their first set of leaves then put them under the 400w cmh

 

[greenisgold]

I have also found that if you keep the lights on for the first 2 weeks 24/0 that this also helps compared to 18/6. I was an 18/6 grower from day one for years until an experienced grower said I should try 24/0 and it helps for sure. After 2 weeks I flip to 18/6 which I know is a hot topic.

 

[DIGITALHIPPY]

To whoever asked: I started my seedlings under fluros until they developed their first set of leaves then put them under the 400w cmh

thats the problem. u need to have seeds one inch or less away from floros to prevent strech.
i like to germ under 600w and 1k w mh light it prevents almost all strech and the seeds grow faster.

 

[kronik]

Wow guys, this really did turn into a super-informative thread.... I have learned a lot - thanks to all who replied!

I believe my seedlings stretched due to not receiving any light the minute they poked their heads out... I might still germ in darkness next time, but the light goes on the instant I see any green.

I am not going to even bother with the dome next time (I can get the RH to 70% in my closet with ultrasonic foggers) and now my temps are in the mid 70s - with the dome on they hit the low 80s so that might have contributed as well).


At any rate, I germed 12 and managed to salvage 6 ( I buried them higher up in the soil to combat the lanky stems ). They seem to be taking off now - I've attached some updated pix.

Thanks all!

kronik

 

[JohnnyToke]

3) WaterFarmFan, Johnnytoke, Country Mon - my very first grow attempt was with rapid rooters and it failed miserably - I moistened them thoroughly and by the time I woke up the next morning they were like dried cat turds. Rockwool holds water like a camel - after 3 days my cubes are still moist!

I have never used rapid rooters. I use Jiffy Peat Pellets from Walmart which run about $2 for a pkg of 25. they sit in tap water for about 20 minutes to expand. then I place new germinated seed in with root down, cover and once sprout is up (1 -2 days), they need water about every 3 days after that. I place them in small clear 6 oz plastic cups so I can watch the roots. once the plant is well rooted in the peat pellet, I transplant to hydroton in hydro system for veg.

i have no stretch problems, no ph problems, no disease problems, no stem rot problems. I have a 100% success rate using these cheap jify peat pellets. I had all of the above problems using the small rockwool cubes and had about a 50% survival rate. I have several hundred of these cubes leftover and collecting dust in the attic....lol

one more thing, keep your sprouts under light 24 hours a day for the 1st couple weeks. this will also prevent stretch assuming you have your lighting close enough in the right color (4000k - 6700k).

hope this helps.

regards,
JT

 

[FreezerBoy]

Rockwool does not cause stretch, desease, stem rot or pH problems. It does not require pH adjustment for clones or seeds. If you're having these troubles, look elsewhere for correction.

 

[JohnnyToke]

Rockwool does not cause stretch, desease, stem rot or pH problems. It does not require pH adjustment for clones or seeds. If you're having these troubles, look elsewhere for correction.

FreezerBoy, im sure you and some others may have rockwool and your seedlings dialed in and get good results with them.

I am only speaking from my personal experience with rockwool & seedlings. we just didnt get along...lol im sure it was more me than the rockwool.

mine did require ph adjustment daily and that was using ro water @ 10 ppms or less. I used the rockwool conditioners etc. didnt help. it was either to wet or to dry and seedlings suffered for it. I couldnt babysit my seedlings by the hour as some of the growers here have the luxury of doing. I could only check on them once a day. if the rockwool dried out, they died, some stunted then would die about 2 weeks along and the culprit was stem rot from the rockwool holding to much moisture. im not sure about disease but on a few, I did have some funky algae looking stuff grow on top of the rockwool next to the stem and a week later, they flopped over dead.

after struggles thru 2 grows with the rockwool cubes, I rolled over to Walmart one day, purchased a 25 pack of jiffy peats for $2, tried them and have never looked back.

Personally, jiffy peat pellets cause zero problems for me while my rockwool seedlings struggled to survive. coincidence? maybe. who knows. all I know is I dont have to adjust ph daily, no baby sitting more than once a few minutes a day. females grow big green bud, males meet a less fortunate fate. its all good.

another plus, jiffy's are cheaper than rockwool and hassle free. no conditioners, dont have to worry about them holding to much moisture etc. I have used them for my last 3 grows and havent lost a seedling yet.

so since they work for me, are cheap, available at Walmart (no trips to the local hydro store or online ordering), hassle free etc etc, I thought I would recommend them to the community.

regards,
JT