I'm guessing I need to increase or decrease the nutes that I am adding to the water in a soil grow, but I don't want to go the wrong way. I'm using the 18-18-21 MG Tomato Food - a little less than one scoop (two tablespoons) to 1½ gallons of water per watering (using 9-gallon aerated pots). I water when the top two inches of the soil gets dry, which is about once every 3-4 days. I know some will say I should use more expensive nutes - but this is a budget grow and this is what I can afford. It seems to be working great, as this is my second grow and the buds are doing fine. I just need to know if I should flush and use less nutes or if I need to add more nutes due to deficiencies. Thanks for your opinions! BTW, it's a White Russian in 4th week of bloom under 2,700K 55-watt CFL's (five bulbs per plant). The first pic below shows the leaves that I am concerned about.
P.S. - I've looked at some of the leaf damage diagnosis charts online, but I can't figure out if the symptoms shown in the first pic above are due to over- or under-feeding. I also add one shot glass of H2o2 per 1½ gallons of water.
if you have been feeding every time you water, then definitely back off. It looks like some calcium def by the spots but some burn on the edges probably causing lockout by salt build up. flush a lot. If you know we are going to tell you to use different Nutes then... I won't say it.
hey there. So to me it looks like a combo of two things, that's why it's hard to diagnose. I could be wrong but seems like you have a slight nute burn going on awsell as slight light burn. I wouldnt worry about the light burn; cfl's have to be close to the plant to emit a usable spectrum for growth and fan leaves being burnt wont effect your harvest. just make sure your buds (as of now in 4th week your pistils) dont get burned. As for the nute burn looks like its not too bad, Id just lay off the nutes for the next two-three feedings then continue like normal but 3/4th the strength you've been working at. As for the h2o2 I wouldnt be adding that every watering. Also be aware that old nute burn will not disappear after you fix your feeding and that burn will continue for 1 week even after you stop feeding because the old built up nutes are still in the soil and plant. The next time you water do a small flush by just giving them double the amount you normally do of plain water. hope this helps!
Thanks!!! I do place the bulbs real close and I have noticed that some of the yellowing seems to be a result of that. I think I over-fed when I put them into bloom and switched to MG from a more expensive nute that I couldn't afford to use on six plants. I was using a full scoop at first, but since then I have backed off to about ¾ scoop. Are the yellow spots more of a nute-burn thing, or do they result from nute deficiency?
they are way way overdosed, I'm 100% sure of that. try using between an eighth and a quarter strength every OTHER watering. and when you give just water send plenty of water through the soil