Hi folks, just a quick question. I'm growing some bag seed under HPS lights but I have notices that the leaves are not really that green anymore, more a light green, almost to the point of turning yellow? Is this a condition of the lights or a nutrient deficiency? Cheers
How old are they? Do you know the pH of your water/soil? Do the edges of the leaves harden and start to curl up? What is the tempature in your room and how far away is your light? I think yellowing leaves is probably the most common problem people have but unfortunately, there is more than one problem that causes this so more info is needed.
How far are they? into flowering? If so the leaves slowly change to yellow signaling the end of the plants growing cycle, it also could be a nitrogen deffiency
Cheers for the interest folks, I just saw the other thread regarding yellow leaves too so now appreciate it could be one of a number of things. I just re-potted them into deeper pots filled with a combination of top quality top soil and tomato grow bag soil, as for the PH of the sol, no idea, I'll et a soil testing kit at the weekend. The lights are 600w HPS and are 24 inches above the plants. I've watered sparingly using the 'stick your finger in 2 inches' method and have only given them 2 lots of fert in the last 3 weeks. They were originally sown and grown in potting compost from a garden centre, said to be idea for potting plants and so on. I also bought some tomato fert at the weekend, will that be ok to use on them?
You cant go wrong with a well rounded fert. like 10-10-10, but when the flowering starts you want to cut back on nitrogen and find a quality fert with a higher phosphorus like 5-15-5 the dose should be about a quater of what they use for regular feeding like a 1/4 table spoon to a gallon of water, this is the ppm or parts per million.