The 2 bottom sets of fan leaves (4 leaves total) are discolored and have either grown rust colored spots or have a long patch of necrosis along a margin. It's only 4 leaves, but they're each bigger than my hand. The veins are red on the top of one of the leaves, but not the underside. The tip and margins of one of them are gray/brown and curling up. I've also noticed slight yellowing on some of the new growth at the bottom of the plant, but everything above the first 4 nodes (including fan leaves) looks very healthy. My best guess is potassium or magnesium deficiency, but the yellowing growth at the bottom is what's throwing me off. Maybe both potassium and nitrogen deficiency? What type of medium; soil or hydro? Soil What brand and type of soil? 66% Promix BX, 17% FFOF, 17% perlite Indoors or outdoors? Indoors What strain? LSD by Barney's Farm How old are the plants? About 2 months from seed, 3 weeks into 12/12 What type of lights and how many watts? 250W HPS, shared with 1 other plant How far from the lights? The top cola is about 8" from the light What is your watering frequency and source of water? About once every 1-1.5 weeks with tap water What, how much and when was it fed? NPK? Last feed was almost 3 weeks ago (2 tsp. Tiger Bloom (2-8-4), 3/4 tsp. Snow Storm Ultra (0-0-3) to 4 gallons water), then a watering a week ago. I feed every other watering. What are the temps and humidity in the room? 70s during lights on, 60s during lights off. About 30-40% rH What size pots? 5 gal Any bugs? Look real close. Nope Any other pertinent info? This is my first time using promix and this stuff is absorbent, so I've been watering a lot less frequently than when I was using soil, but I still up the dosage very gradually as I usually do. So I'm thinking that's why there's a deficiency, they're pretty much being fed every 2.5 to 3 weeks at 1/4 the recommended dosage. Also, the last feeding was also the first after going 12/12 and I wanted to try something new and flush the soil to get all the veg nutes out and replace them with flowering nutes. So I flushed with 15 gallons water, waited about an hour then fed with 4 gallons of the concentration listed above. My best idea so far, assuming it's N and K the plant needs, is to feed with 1/4 strength Grow Big (6-4-4), 1/4 strength Tiger Bloom (2-8-4), and 1/4 strength Snow Storm Ultra for the additional K (0-0-3). The Grow Big and Tiger Bloom would pretty much add up to a 1/2 strength dosage, and the Snow Storm would just be a nice supplement. Any 2nd opinions? PS. Sorry, no pics yet cuz they're still sleeping, I'll put some up later when I get a chance.
The second last picture is new growth at one of the bottom-most branches, and the last is of the top kola for an idea of the plant's general health
http://forum.grasscity.com/indoor-marijuana-growing/374679-essential-plant-nutrients.html click that link and look for what problem is yours, this should help you out
Thanks guys, I ended up feeding 3.5 tsp Tiger Bloom (2-8-4) to 4 gal water, I'll just monitor her and see how she goes
The symptoms have stopped spreading, but now the tips of all the leaves on the entire plant are yellow/brown and curling up, some are curled right up into a little roll. Burn, deficiency, overwatering?