Preventing leggy petunias requires dedication and a little bit of care. But keep up this cycle throughout the season, and you will be rewarded with a full and splendid petunia garden.
1) Make sure you keep the soil moist
If you have petunias in a container or hanging basket, they tend to dry out faster, and you may need to water them every day. Check their moisture level each morning and give them water when it seems needed.
Petunias in the ground may need water every three to five days.
2) Deadhead blooms AND seed pods
Petunias will bloom most prolifically if the spent flowers are deadheaded. But you also need to remove the seed pod if you want to stop leggy petunias. The seed pod looks like a little green or tan bud nestled at the base of a star-shaped group of tiny leaves. To make sure you get the bloom and the seed pod, nip or pick off the flower stem below this section.
3) Prune the branches regularly
Preventing leggy petunias requires pruning the branches by one quarter or half on a regular basis. Your petunia plant may be in full bloom when you do this, but it will keep your plant looking full and colorful, so it is worth it.
You can cut back all the branches at once, and you will have a full, compact blooming petunia plant in just a couple of weeks.
Or you can just cut back some of the branches scattered evenly throughout the plant. Those branches will regrow and rebloom, and then you can cut back the remaining branches two weeks later.
Be diligent with these techniques and your prolific bloomers keep on producing.