Question
I am in the North Coast, zone 9, 1 mile near the ocean, Humboldt County.
I use a foliar fertilizer about every two weeks on my roses during the growing season. I also use Neem extract as a pesticide, mildicide, etc. (also sprayed on). I need to know how soon I can use either one before or after use of the other; do they conflict with each other, or does the use of the fertilizer undo the pesticide activity of the Neem? How do I use both on the same plants?

Answer
Rose leaves are like a sponge so they will take up anything that falls on them. Foliar fertizing means that the plant gets all of the fertilizer in a short time. Neem tends to coat leaves so that could delay fertilizer from getting through. Also when you use an insecticide most of the time, then you not only kill any bad bugs, you also kills the good bugs. Normally you use an insecticide when you see the insects and that way only the bad die. After spraying with Neem, look at the leaves and see if there is an oil residue, then sprinkle some water on the leaf and see if it runs off. Nothing is wasted because even if the foliar feed slides off, it will still be taken up with the roots. If the fertilizer stays on the leaves, then you have your answer. Try to spray in the morning or afternoon. Roses release moisture during the night time and the fertilizer won't be taken up as well as during the day. Hope this helps. Lynnette