Answer: In gardening terms, deadheading is the removal of spent flowers. Pinching out the dead flowers will stop the plant from directing its energy into developing seeds and instead will develop new flowers. So, yes, pinching off the spent flowers is a good idea. In fact, you should pinch off the entire flowering stem along with the dead flower. Doing this will encourage your petunias to produce more flowering stems which will keep it dense and bushy as opposed to thin and leggy. In addition, if you pinch out the very tips of each of the stems your plant will produce two new stems where there once was only one. In mid-summer petunias bloom their little heads off so you may be going out every day or two to pinch out faded flowers. If you do, you'll be rewarded with a riot of color all summer long.
You can feed your plants with Miracle-Gro.
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