i am growing jack herer for about three weeks from seedling so far i am amazed at my results they were growing really well and all of a sudden one of my plants starts getting yellow on the leafs not in veins but blotchy now they are all going blotchy and the leafs are turning up , i am growing indoors in pots of soil , with a 600w high pressure sodium lamp , iam setting my ph to 5.5 as told in hydroponic shop and am using canna vega a & b grow feeding 2 litres a day between six plants that are about 8-10 inchs tall the temp is 74 degrees and humidity is 40% i am a beginner as in that this is my first time so am i making the ph too low plants to close to lamp overfeeding underfeeding or is there something else that could be doing this
http://www.overgrow.com/growfaq/1111 i dun remember who this link came from but its the best i know of and thats saying a lot
im not exactly sure of what your talking about, but if you mean the entire leaf is covered in medium size yellow spots, try giving 1/4 - 1/2 tsp. of epsom salt per gallon of water.... worked in 3 days for me
take the ph up to around the 6.0 mark, 5.5 is the setting for rockwool not soil. if you dont have a ec meter then just feed at 1/4 streanth (5ml a+b per 10lr of water) and only every 3rd watering. for the other 2 waterings use plain ph ajusted water. when bottom leaves start to show an even loss of green (yellowing) feed every other watering and/or up the feed to 1/2 streanth (1ml a+b per liter of water) increase feed slowly over time as plants grow. remember that the 20ml dose is a max dose not a set dose. never feed every watering, only every other as a max. if your watering every day either your pots are to small or your over watering. if your using tap water then dont forget to let it stand for atleast 24hrs before you add feed and ph ajust. that will let things like clorine escape which is harmfull to your plants and also will give you a false ph reading. canna has ideal amounts of mg for the cannabis plant so no extra mg (epsom salts) shud be needed. if your plant is showing signs of poor mg then its cus the mg is locked out due to the bad ph.adding extra mg will do nothing apart from help block other trace nutes and poison an allready toxic soil.