I’m having a problem where the new growth on my seedlings die off, stop growing up top, and turn slightly yellow or lighter green
The roots on the edges of the container brown and new ones grow but no new plant growth. So the seedlings are still alive.
Is this a problem with fungus gnats? Overwatering?
A few seedlings appear to have a lot of small bugs in their soil. Some look like mites, some young fungus gnats.
I’m using a Neem oil solution to water these past two weeks.
Overwatering and fungus gnats could be at least part of the problem, and certainly aren’t doing the seedlings any good. On top of that, in my experience, roses and oil don’t mix, at least not when it comes to being sprayed outside of dormancy. In fact, the symptoms of oil-caused phytotoxicity are rather similar to the ones you’ve described. I’m not sure what a Neem oil soil drench would do to rose roots or to the medium itself, but it seems a bit risky to me.
Letting your seedlings’ growing medium get at least slightly dry on top before watering again will help if you suspect that you may be overwatering. If you do have fungus gnats, and BT-based mosquito control granules are labeled for them where you live, try adding those to your watering solution according to the directions instead of Neem oil. If you have insect or mite problems on aerial plant parts, roses are much more tolerant of insecticidal soap.
Stefan
I have used it before without issue but the seedlings were already having these problems before I started using it.
The solution is 8oz water, 1/8tsp neem oil, 3 drops dish soap and each seedling is getting 1tbsp of this solution.
It was mainly for the fungus gnats. I’ll increase time between waterings to see if that helps and hold off on neem oil