I am having a real issue! I have several plants that are 3-10 days into flower and most of them have these rusty looking patches (necrosis maybe?) on the lower leaves. The leaf stems are red and the edges of the leaves are drying up. The affected leaves pop off the stem if even lightly touched. I am using 1000 hps lighting, plants are grown in Fox Farm ocean forest. I am using fox farm Big Bloom and the ph is about 6-6.5. All of these plants were perfect and beautiful in the veg room and then this!! Any help is greatly appreciated-I am freaking out
Hey man, this could be a few different things. It kinda depends on what you have been doing, that being how much/when you're feeding them. It could be that they were a little low on nitrogen before you switched over to 12/12 and now they are very deficient. Bloom ferts. have low doses of (N), most plants at the end of the cycle usually show signs of the (N) deficiency. There is not much that you can do but give them a very small dose of (N). A larger dose may effect your flowering. Alternatively, Plants, during flowering need a lot of (P)&(K). The rusting looks more like that of a potassium(K) def. than anything else. Both (N)&(K) def's cause purple stems, but the rusting and brittle stems is more likely (K) def. which is much more in your favor, just give em the "heavy feeding" on the back of the FF bottle. Wait a few days, maybe a week, and you should see signs of improvement. Also, if you're PH is off it will lock out nutrients and that will cause deficiencies. Hope this helps, if you have any other questions let me know. Peace.
Lazer420-Thank you so much-your post was very helpful! I have been going lightly on the Big Bloom fertilizer (I've over done it in the past) 1 Tbs/gal. The FF bottle says 1/2 cup per gal. for heavy feeding-that seems like a HUGE increase. What do you think about going to 4 Tbs/gal? Also, could this be a problem with lighting/air circulation? I have 9 plants in a 10x10 space temp 80-85, humidity 50-60%, my ph into/out of plants is about 6-6.5. Thank you again so very much! I am really worried about losing everything.
From what I can see on the newer photo it looks like your leave margins are standing up and also the leaves are pointed up. Both of these as well as the ridges between the veins are all signs of heat stress. 80 degrees is too hot. Get another fan in there, open a nearby window, keep cold water in your humidifier, or open two nearby windows, etc. try to keep it between 68-78 and that should stop. your ph is good so I think it's a (K) def.