Answer: There is no set schedule for watering, it depends on your soil type -- and on the weather. Both over watering and under watering can both cause drooping or wilting due to root damage. In my experience, watering twice a day would be excessive. I would expect you might need to water at most every four or five days in the extreme heat of August -- and assuming there is no rain.
Your goal in watering is to keep the soil evenly moist like a wrung out sponge, not sopping wet and not dried out. To know if you need to water, dig into the soil with your finger. If it is still damp, do not water yet. With new plants, there is sometimes a situation where the soil mix right around the roots (the potting mix) dries faster than the surrounding soil. This is why it is important to check the soil by feeling it.
When you do water, apply it to the soil surface and water thoroughly and slowly so it soaks down to the deeper roots. After watering, wait a few hours and then dig down to see how far the water soaked in; it can be surprising. In general, it is better to water deeply less often than to water lightly every day.
Using an organic mulch several inches thick over the root area will help reduce watering needs as well as feed the soil gradually as it breaks down over time. The mulch is really important in helping to keep the soil cooler and moister and encourage rooting.
Good luck with your new plants!
Q&A Library Searching Tips