Eh. When it comes to outdoor garden plants, conventional wisdom says watering in the morning or evening is ideal because it allows the plants to get a drink before the blaring sun comes out and dries the soil again. If you water your garden at 2 PM in mid-summer, you risk the water evaporating too quickly, before your plants have a chance to use it. For houseplants, the time of day you water is less important because they’re in a closed, climate-controlled environment. Morning watering is still a good idea because it gives the soil all day to dry out in the sun, protecting the roots against too much prolonged moisture. Of course, if you happen to water on a cool, cloudy day, the soil will dry more slowly. So make it easy on yourself and feel free to water whenever you remember. If it’s midnight and you suddenly realize your peperomia is parched, don’t delay until morning and risk forgetting about it for a few more days.