Geraniums need to be watered sparing and since they last till summer is here therefore they are a source of colour in the Garden much longer then other plants.
Water your plants as needed. Geraniums are considered relatively drought resistant, but that doesn’t mean you should never water them. To tell if your plants need to be watered, check the soil. Use your fingernail to scratch just below the surface of the soil–if it is dry or barely moist, you should water your flowers. It is important to let the soil dry out between watering.
For geraniums in pots, make sure that you give them enough water.
Water the plants until the water runs out of the bottom (hence why you need holes in the bottom of your pot.)
Keep the compost flowing. Each spring, you should add a new layer of compost around your geraniums. Place 2 inches (5.1 cm) of mulch on top of this layer of composted soil. The mulch will help to keep the soil moist, and will also reduce the number of weeds brave enough to grow around your geraniums.
Keep your plant healthy by removing dead flowers. After the flower has bloomed, remove the dead flowers and parts of the plant so that it can regrow healthy and strong.
Separate your plants every three to four years. Once your plants have grown large (and most likely extended their boundaries a good deal,) you should separate the plants. Divide the plants in late spring. To do this, lift the plants (and their roots) out of the ground, separate the plants by the clumps they have grown around their stems, and replant them.