When should you water outside plants,AM or PM?

It is a better use of water if you water before the sun is up (hot) or when the sun is setting. There is less evaporation that way. But watering other times will not hurt the plants.

A.m. If you water pm the water on the plants overnight can cause mildew and disease.

I did a tomato question on home talk .one said morning one said after 7 p m . I like the morning myself. .I am a early raiser .

AM. Some plants develope mould if warered at night. They so not have a chance to dry off.

While it's cool, early morning

Technically, the general answer is am to avoid mold and fungal growth. BUT if you live in a hot, dry area where the water will evaporate quickly, water after the heat of the day - and try to use drops, not mist, as low to the ground as possible - either way- to avoid watering the 'air'.

Typically morning is best. Evening watering may cause certain bacterial or fungal growth because the leaves of the plant do not fully dry out. I say that but all the years I worked, I always watered in the evening because that was the time I had to do it.

All depends on your climate. Early am watering is best if you live in a humid climate. If you live in an arid climate, you may also water in the early evening. Where I live, humidity can be less than 10% in summer. I water in the evening to perk them up and gives the water a chance to soak in rather than immediately evaporating in the summer heat. With low humidity there is much less chance of disease, fungus and mildew.

in the morning and if you need more as soon as the sun starts to go down