4. Water Regularly
If we could point to two things that are downright killers of petunias, it would have to be overcrowding and overwatering. You don’t want to plant them too close to one another – even novice gardeners should know that plants need more than enough space for them to breathe – and when it comes to watering, a lot of novice gardeners will over-do it.
Petunias need to be watered regularly, but you might be surprised to find out that it’s not nearly as regularly as you think. When in the early stages, you’ll want to water at least twice a day (but not in such large volumes that you risk drowning your plants!) – but once they’ve transformed into a larger bush, watering can be brought down to once per month.
This only counts when they’re planted outside in an area that gets plenty of access to natural rain: When petunias are planted in pots, increase watering to at least once every few days and adapt as needed.