You should wait to prune the plants until they are getting 6 or more hours of sun a day and they are filled with blooms. Once blooms start to die, you can start deadheading. Unlike deadheading by hand, the plant will do best with a sharp cut. Choose 1 that has several dying blooms on it. Find a point just below all the dead blooms. Aim to prune them below the majority of the spent blooms, if possible. Although you must cut back portions of a healthy plant to encourage new, thick growth, pruning petunias will extend your growing season. Doing regular pruning will help you avoid pruning off all your stems at once, making them look bare for a few weeks. Occasionally, you will need to prune off a healthy blooming stem. If a stem is looking long and leggy with lots of dead blooms, sacrifice the healthy bloom on the end so the plant will bloom longer. If possible, do it right before you leave for a trip, so that you will return when the petunia returns to full bloom. Do it after a pruning session to encourage new growth.
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One-sentence summary -- Allow your petunias to start blooming. Get a sharp pair of pruning shears or scissors. Pick up a petunia stem gently. Cut up to 1/2 of the petunia stem with your sharp shears. Prune 1 stem weekly on a small petunia plant, or prune 8 to 12 stems in a large hanging basket. Time a large pruning session for mid-summer, if you were not able to do it weekly. Fertilize petunias with a liquid fertilizer every 2 weeks.

Article: Your fish will need to be placed in a temporary holding tank while you clean and refill their permanent home. So find a suitably sized bowl, container or bucket that will serve as a temporary holding tank. Use a bowl or container that has not been washed with soap, as the residue from many soaps can be harmful to fish. You will need to age the water you will use in your holding tank to equalize the temperature and PH balance. Let the water sit overnight after filling the temporary holding container to achieve the proper temperature and to allow the levels of chlorine in the water to neutralize.  If you don't want to wait for water to age overnight, then it is wise to treat this water with a dechlorinator. These products neutralize the chlorine levels found in most city and municipal water sources.  Make sure the water in this temporary holding tank is the same temperature as the water in the permanent tank. You may also wish to cover this tank with a lid to prevent the fish from jumping out. Don't place the temporary holding tank in a window or under a bright light, as the heat from these sources can raise the water temperature, potentially harming your fish. Also, be sure to place your temporary holding tank in a place where children and other household pets can't bother the fish. Take your fishnet and scoop your fish out of the fish bowl and put them into the temporary holding tank of fresh water. Use a large bowl for this holding tank so that your fish have plenty of room to swim.  When using a fishnet to transfer fish from one container to another, make sure the containers are close together. This will reduce the amount of time the fish is out of the water, thus reducing its stress levels.  Alternatively, you can use a small, clean bowl to transfer your fish. Make sure the bowl does not have soap or soap residue on it and select a rounded bowl with smooth edges. When using this method, simply dunk the small bowl into the fish tank and allow the fish to swim into it. Be patient and don't chase the fish around its bowl. This could stress the fish out. While you undertake the cleaning process, make sure to keep a watchful eye on your fish in their temporary tank. Look for changes in their behavior, color and activity levels. The following signs should be an indicator that the water in the temporary tank is too warm.  Hyperactivity Changes in the fish's color “Yawning” at the surface of the water (although some fish, like labyrinth fish, breathe this way) If the water is too cold, your fish may exhibit the following signs: Inactivity Sitting on the bottom Changes in color
Question: What is a summary of what this article is about?
Find a holding tank. “Age” the water. Avoid direct light. Move your fish. Monitor your fish.