A newbie here, just wanting some reassurance/advice. I have 4 plants, 3 weeks old, growing in soil 50cm under a 400w bulb in a small grow room with intake/outtake fans and an oscillating fan. I water every 2-3 days and mist daily, the humidity is around 35% and the temp between 70 (night) and 90 (day). All SEEMS to be going okay, the pics show one plant but all are the same. My worries are the stretching (may be due to them growing on a window sill for the first 10 days) and the slight yellow/brown mark on the larger fan leaves (could be due to me mistakenly giving them ferts too early ,won't do that again), and the lighter colour of those fan leaves. What do you think guys, am I being an overprotective parent or are there improvements to be made here? I had one die early on and don't want to lose any more. Thanks.
The soil is just an ordinary loam based soil for seeds and cuttings (John Innes brand from a garden centre) but I have bought some Biobizz All-mix soil from a hydro shop for when I transplant them into larger pots in a couple of weeks. The bulb is a Philips Son-T Agro 400w HPS
well your temp is a bit high. should try to bring it down a bit if you can. especially with a low humidity. With a 400w hps, it shouldn't be stretching, but like you said it's probably the growin on a window sill that stretched them. You can try re-burying the stem into the soil so just the catyledons are showing.
Thanks for the replies guys, I will put an extra cm or two of soil to help the stems. Is there a time during veg when the stem starts to thicken quickly or will it happen gradually becoming only as thick as it needs to be? Also I have NO money left after building my grow room for more ventilation kit. I am trying to open the door during the warmer hours of the day but this is not always possible (or indeed safe - it's in my garden shed!). I hope this will do until the weather gets cooler (shouldn't be much longer in the UK!). I know improvements can be made but if I carry on as I am do you think my plants will survive so I will have at least some harvest?
I also have a couple questions for you... Do you know the strain? What kind of water are you using? Are you measuring/adjusting the pH? The yellowing looks a lot like nitrogen deficiency probably due to the pH being slightly too high. This happened to my plants more than once early in veg. If you can't measure the pH and are using tap/drinking water, you can ad about 2-3 tbsp of white vinegar/ gallon. This brings my pH from about 9 to about 6.
You should have that plant closer to the light source. My plant had 15 leaves by the time it was that tall. I move my lights 2x daily.
The strain is White Widow. By coincidence I picked up a PH test kit today, I'm using tap water (at least a day old) so I'll test it as soon as I can and post the results. How much closer do you think the light should be to the plant. It's pretty hot in there, do I risk heat burn?