We had a nice litte avocado tree sprout in our garden ( lots of avocado seeds in our compost.) It was growing well but recently it's leaves started to lighten in their shade of green. Also, the margins around the older leaves especially have gotten wavy, the leaves have curled downward a little bit, there is little spots on some of the leaves, some decent necrosis on the oldest leaves, some purple shading on the newer large leaves, and it's just not growing at all right now. It's had a new shoot out of the top that has stayed the exact same size for close to a month probably, and it just doesn't look as green as it probably should be. ( not that I'm experienced in growing avocados at all.). I checked the pH and it was probably a little above 7.0. I watered it with some coffee mixed 50/50 with water, then watered a litttle more so that the coffee would get down deep enough in the soil. It's been about a week and the plant hasn't improved. I check the pH again and it's at 7.0 so it might have gone down but not much. Is it safe to give it some more coffee but maybe a little stronger dose this time? I know of other ways to improve pH like adding nitrogen but I wanted to find a way to change it fast. Also trying to use what I've got and not trying to have to go buy something from the nursery if I don't have to. There could be a nutrient deficiency in the soil too since there were tomato plants growing there this year but first I need to get the pH right. Google says avocado trees like 6.5-6.2 pH.
posted 2 years ago
My main worry about adding more coffee is will I burn it by giving it too much nitrogen. The tree isn't going to just keel over and die anytime soon most likely but it would be nice to get it growing again.
The leaf looks like what you need is some Epsom salts (MgSO4) sprinkled around it.
Instead of coffee grounds you want calcium sulfate or another mineral salt that is a sulfate or sulfide
Lots of times just a small amount of sulfate or sulfide will jump start the soil organisms and thus benefit the plant.
The trick here is to not try for large jumps, you want small movements in pH, that way you won't go too far and create a new problem.