Hello all, I've got some northern lights autoflowers going in a green house. They've come along so quickly, i feel like i've only just started giving them nutrients. Though they most look completely healthy, many of the plants have these yellow tips, on both new growth and old. I've done one grow previously, and one issue was the pH was off the whole grow, as the city water is a 7.8. This one is a soil grow with happy frog soil. Ive been using a bluelab ph pen to check and adjust the water every watering in conjuction with pH down. I shoot for a 6.8. For nutes I am still on my vegetative growth fertilizer. With the autos flowering just snuck up on me so quickly and I haven't picked up anything for flowering.. 3 of the plants that are the furthest along display these very yellow tips. It is only the tips. Poking around online the closest thing it resembles is a copper deficiency, though i've been pretty careful about the pH this time around. Any insights would be appreciated, thank you.
Discoloration on the tips of the leaves mean nute burn. You might consider investing in a TDS/EC tester pen. They're pretty cheap and tell you just how weak or strong your nute mix is. The pH range for soil grows is 6.3 to 6.7...so shooting for 6.8 is out of range. You get the pH of the liquids (both water and feed solution) within this range before giving to your plants. I've found if you keep the water/feed going into the plant within proper range, the runoff pH will be about right too. But that is the correct range for pH on soil grows and I think you're hitting them just a bit too hard with the nutes. Some people like to see tip burn on their plants. I'm not one of them. I give my plants the least amount of chemicals I have to to keep them healthy and thriving. I don't want to give them anything more than that. Lots of nutes are not the key to a fine large plant and a nice harvest with heavy, resin coated buds....it's LIGHTING. The better quality lighting they get during veg, the faster they will grow and more developed they will be and the better quality lighting they get in flower will determine the size and thickness of your buds. just paid $100 for 4 cfl tubes for one of my T5's. I called the grow house and spoke with one of their team members about veg tubes before I ordered and these, though about 3 times the cost of the typical tube to go in the T5's, are KILLER good. Can't wait to get some plants under them and see how good they perform. Just learn how much you need to add to meet their growth needs with the nutrient mix and work on upping your lighting if you want to increase your harvest with bigger better buds. Happy growing! TWW
woops to ph, will amend. In all honesty it hadn't occurred to me it could be nute burn, i've only added a dash to water due to the plants small size, but ill let them tough it out and hold off on the nutes. It'd be nice if we'd get some sun, its been raining for 2 weeks now. Thanks for the inputs fellas, its appreciated.