Reasons Why Petunias Do Not Bloom and How to Fix Them
1. Water
Around the flowering period, the water factor needs special attention. If water is insufficient and cannot meet the needs of flowering, the plant will not be able to bloom; likewise, if it becomes waterlogged and the roots are damaged, it also will not bloom. Specifically, follow one general principle: "water only when the soil is dry, but do not let it become waterlogged." That way you will not go wrong. In other words, an adequate water supply is necessary, but excessive waterlogging must be avoided. The right amount and the right conditions are the key to blooming.
2. Light
If light is very dim around the flowering period, the plant will find it very hard to bloom, because photosynthesis will be very weak. So what we need to do is provide sufficient light so it can carry out photosynthesis fully and accumulate enough nutrients.
3. Temperature
This is also easy to understand. If the temperature is unsuitable, or even causes it to freeze, then getting it to bloom is almost impossible. So keep the temperature regulated at around 20°C to provide ample assurance for blooming.
4. Fertilizer
It may not be especially important at ordinary times, but during the flowering period it becomes very necessary. If some is not applied properly, it may be unable to provide sufficient nutrients to support blooming. Therefore, it is best to spray some (KH2SO4) solution during the bud stage, which helps it bloom and makes the flowers larger and better.
5. The Time Has Not Yet Come
Sometimes, because of the variety, or the special local climate of the area or that year, the plant will indeed delay blooming. Ensure all the various factors are suitable, and it will always bloom eventually.