Slow Growing Seedlings

I have this question posted in the Newbie portion as well, because I'm a new grower, but I thought I'd ask it here too.

I have a problem with the growth of my aproximately two and a half week old seedlings. They are growing, but slowly it seems. There are nine seedlings, each in their own large bucket with nutrient-rich soil. They sit in a 3 foot long, 3 foot high, and 2 foot deep box painted white (for reflection), with two 18 watt flourescent lights on the top. The seedlings are about 4 inches from the lights. I have given it about 24 hours of light for the last two weeks, and have been watering usually everyday (with small amounts). There is a small mixture of yeast/sugar water mix for CO2 production. The temperature in the box is usually around 65-70 degrees, and the humidity is good. There is virtually no ventilation system, aside from me opening the box daily, and airing it out for 10 minutes, and blowing on the plants to strengthen them. The largest seedlings are about 4 inches high, and almost none of them have a second set of leaves (just the first set). I've seen a lot of pictures of other people's plants after two weeks, and they are always much bigger and more developed than mine. At this growth rate, it seems they will take months before they're mature enough to flower. I'm just wondering if anyone thinks I'm doing anything wrong? Why aren't they growing faster? Is it a CO2, lighting, or ventilation problem? Thanks for any help. I'll post pics soon hopefully.

Don't water everyday. Water more but less often. Temp should be warmer that is fine for the low side. You need ventilation. They also need a fan in there to provide air flow. You wouldn't feel well either if you were only getting 10 minutes of fresh air everyday.

Got some pics of my seedlings, these are approx. two and half weeks old. Does anything look wrong with them? I took the advice of installing a fan to circulate the air, and strengthen the stems, and I also moved the plants closer to the lights. I'm hesitant to add ventilation holes in the box (as it is, its not air tight anyway), because it is in a place where the temperature of the room is pretty cool (like 45-55 degrees F), and I would rather keep the heat of the box locked in. Which do people think would be worse, colder temperatures, or lack of substantial ventilation? Thanks for the info.

wlhigh said:

Got some pics of my seedlings, these are approx. two and half weeks old. Does anything look wrong with them? I took the advice of installing a fan to circulate the air, and strengthen the stems, and I also moved the plants closer to the lights. I'm hesitant to add ventilation holes in the box (as it is, its not air tight anyway), because it is in a place where the temperature of the room is pretty cool (like 45-55 degrees F), and I would rather keep the heat of the box locked in. Which do people think would be worse, colder temperatures, or lack of substantial ventilation? Thanks for the info.

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they look really stretched to me, good move moving the light closer. I guess the cold temp/ventaliation issue is a catch 22....I would vent it and add a small heater of some sort, or add more lights for more heat!

I dunno, im new at this!

mine are also growing slow, they are tall sprouts too. but not growing too fast

your plantes are stretched becase the light is to far away realy the light is not nowhere good enough

my 3 nyc diesels were going straight up under 155w 2' fluoros and the day i switched to a 250 mh the stretching totally stopped and leave production began. the metal halide totally stopped the upward growth. perfect. gonna be some controllable plants with a nice fat yield i hope

WlHigh,

Your problem is simple, everyone here has given you the awnser.

First, you need to invest in ALOT more lights, make sure they are 6500k when vegging. If you wish to continue with flouro technology, then you should research T5 HO systems. Second, ventilation is MUCH more important than cold. If you invest in more lights, I assure you even 4 more CFLs would bring the temp up so where you can still ventilate and not have to worry about temp. The reason venting is soo important is because it is crucial to gas exchange, your plants use ALOT more CO2 than baking soda and vinegar can make up for. Also fresh air exchange prevents stale air which ultimately prevents HORRIBLE mold issues.

I was in your shoes a couple years ago. I made a box, 3' wide X 2' deep X 4' heigh. My box was hot, and plants were growing slow, added more light they look stressed (not bad). I figured me having the box open while home would be sufficient, it wasn't. So I installed 2 pc fans, one blowing in and one blowing out. The exhaust is high to expel warm air. After these two combined moves my plant exploded.


Good luck, keep us informed, and take our advice (for now get more cfls close to the plants).

they grow faster under 18-6 l/d i had the same problem under 24 they some told me to try 18/6 and i never went back to 24 after my frist try, good luck

Under 18/6 they grow faster then the roots do though which can be a problem later in the grow as the plants will start leaning unable to support the height and weight.

never had that problem,18/6 with the light 2" above and 4" side bottem to top clf's. let me kown some more I would look into them

i have my 2 plants under 24 hour light right now, should i switch two 18/6?

they are under 135w CFL

i would try it 18/6. if you like it then keep it going if not stay 24. one thing is people grow what fit them to grow the best with there set up, i would try like i said i did it one and never went back

Okay, drop everything and go throw some more soil in those cups to support those fragile little stems! They are going to topple over any minute now. Next, bring the lights closer to the foliage, like 2-4 inches from the leaves. Seriously consider some higher wattage CFL very soon . I recommend the 5500K-6500K 27W-64W CFLs.


I use 20/4 light cycle at the seedling stage.