You talking outside windows? I can't think of anything that will hurt your plants when you rinse it off. The cleaner will be so dilute by that time it won't matter. Likely vinegar would be the worst...plain soap ( not detergent) like ivory dissolved in some water would be fine as would ammonia....which will add nitrogen to your plants.
Linda C

Vinegar would be very safe for most plants. We do use vinegar water to add acid to plants, that is, acid loving plants.

We wash windows with water/cornstarch solution. Safe AND effective.

Window Cleaner: Mix 1/4 cup cornstarch in 2 qts. warm water and apply with a sponge. Wipe windows dry with a soft cloth.

We use a sponge/squeegee combination on an extension pole. Sponge side applies the "cleaner" and scrubs the window surface, and squeegee it off - no rinsing necessary. Use a microfiber towel for any places you may need to wipe by hand, or to wipe your squeegee off. No streaks, no wasting paper towels. Just did all the windows Saturday. My husband thinks this is the best cleaner we've ever used...

You can make up a spritz bottle with the solution, however, just make up what you can use because it doesn't keep.

-Grainlady