Stretching seedlings?

[Ilovedrugs]

Hi. This is my first time growing from seed, have only started with clones before. Why the stretching? (I did plant the seed very close to the surface).
I read to have 5-7,000 lux for seedlings?
I measure min.15,000 lux at the top of the leaves as this is the suggested minumum for vegetative growth and I wanted to err on the side of too much light.
600w HPS.
Would appreciate any advice.
TIA.

 

[PE636]

Your light appears to be close enough in the pic. Should probably be in the 24 inch range I think. I retired my HPS but that seems about right. They look happy just stretchy! What's your light cycle? A lot of folks go 24/0 or 20/4 for the first week or so before starting 18/6, as they seem to stretch during the dark period. Large temperature swings from day to night also encourage stretching. Also, make sure you have a fan in there, the breeze and air movement makes for stronger stems.

 

[BubbleBucketz]

Refer to the info above.

 

[Ilovedrugs]

Your light appears to be close enough in the pic. Should probably be in the 24 inch range I think. I retired my HPS but that seems about right. They look happy just stretchy! What's your light cycle? A lot of folks go 24/0 or 20/4 for the first week or so before starting 18/6, as they seem to stretch during the dark period. Large temperature swings from day to night also encourage stretching. Also, make sure you have a fan in there, the breeze and air movement makes for stronger stems.

Thanks!
I'm running 24/0 and the temp reaches up to 30°C during the day and down to 23-24°C at night.

 

[PE636]

Only other thing I can think of is HPS isn't the best light spectrum for veg, if you can run a MH bulb in your fixture that may help somewhat.

 

[Jackalope]

Using any HID light for seedlings is not suggested. I don't move my starts to the HPS tent till after the first repot. Starts really should be grown under florescent or LED lights.

 

[CanadianJim]

I usually use t5 ho 6400k lights for seedlings. I tried a 3500k LED recently and got a bunch of stretch. I think it has something to do with spectrum. A higher proportion of red to blue causing the plant to respond by stretching a bit.
T5s are pretty inexpensive, and were a good investment for me, you may want to try them out.

 

[Jackalope]

I should have stated that as one of the new CFL bulbs. I use the T-5's like most people. I have never tried starts under my LED's

 

[Ilovedrugs]

Thanks for the answers guys. First time dealing with seeds has been a nightmare- my mistakes, receiving a batch of poor quality seeds which I needed to have replaced (GYO) etc starting from clones was SO much easier. SO - I realized my 600w light was set at 50%, so I lowered it to a bit over 12 inches and I don't believe the next 2 seedlings are showing any signs of stretching- and there have been no signs of heat/light stress.

 

[SamSmith]

I use my main LED light for seedlings up and through flower. The fan along with the light being at the correct height should keep the stretching to a minimum. The fans are very important when they are young. An ocilating one that changes the direction of the flow strengthens the stems.

 

[Ilovedrugs]

When does a plant cease to be in the seedling stage and can be treated as being in the vegetative stage? For light and nutrient levels etc..??? Eg. I'm currently using approx. 30% nutrient strength (as recommended on the nutrient bottle (hydro)).