What size pot did you transplant into? If it's just an 6-8" (or smaller) pot, you can expect the HPS to dry out the soil out quicker. The sprouts are taking in as much water as they can, and generally the heat makes a difference. Even with an AC unit helping to control the climate in the room, if it's not making the small distance from the light to the seedlings the same ambient temperature, even a slight elevation in heat will cause more evaporation.

If you're using a lot of perlite or vermiculite, or a good deal of any other aerating agent, you'll end up watering more frequently. If this is the case, some peat moss - or a similar moisture retaining substance - should be added the next time you transplant...but you should be careful how much transplanting you do. It's easy to shock the roots by doing it too much. I transplant twice; from 4" germination pots to 10" pots, and then later to a 5 gallon bucket when I know what's going to be staying.

One last thing, make sure the light isn't too close to the tops of the plants by using the back of your hand. You're going to want to get that HPS as close to the plants as possible to reduce stretching. Seedlings can stretch easily, which will generally lead to them falling over. When this happens, I like to make temporary stakes using about six inches of a clothes hanger and bending a horizontal "U" shape on one end. Helps you from having to tie any thread or string around the expanding stem.

Good luck with your grow! :jointsmile:
Mr. Clandestine Reviewed by Mr. Clandestine on . Seedlings 10 days old- a log Hi guys, I am a new member here, since a few weeks ago, I have read many of the articles and FAQ's and I apologise if this is covered somewhere else on the forum (I have looked, honest ;-) Having some BIG PROBLEMS - with my seedlings, they've just turned 10 days old. They germinated in 24 hours thanks to much great love from me! They have recently been transplated because they seemed to be unhappy under a 400 Watt HPS grolux lamp.. I have been extremely careful and have a careful 26Celsius Rating: 5