I have three sunflower plants growing in a 12" pot. I just recently repotted them because their roots had gone through the drainage holes and the bottom leaves started turning yellow and dying. At the same time, there were many small black bugs on them, so I sprayed some bug control that should be sunflower-friendly, but I still see some white fuzzy things that appear to be egg sacs. There aren't any other bugs on it right now, and I plan on spraying the plants again if I see anymore bugs. But after moving the plants into a larger pot, their leaves started turning black at the tips. When I water them, between waterings the soil dries out some but isn't completely dry. It's not very wet, but it's still moist. I water them a little every day. They are on an apartment patio facing northwest, and there are other buildings nearby so the area tends to be pretty shady in the morning and evenings. I was wondering if the problem with the black tips on the leaves was simply due to stress from being moved or if it is a more serious problem, such as the bugs, fungal disease, or just too little/too much watering. Thanks.
Black Tips on Sunflower Leaves
Certified GKH Gardening Expert
This could either be attributed to transplant shock from the repotting, which normally corrects itself once the plant adjusts to the new surroundings, OR it could be a fungal issue, which can be taken care of with fungicide. Although you are letting the soil dry out some, the fact that you say it is still moist leads me to believe that a fungus is likely. Hold off on the watering again until the top inch or so of soil is dry. Also, treat the plant with Neem oil. This will not only take care of the insect problem but it doubles as a fungicide and will help with any fungal issues as well. Here is more information: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm