Geraniums are a hardy flower that can add a splash of colour indoors during a long winter. One particular geranium that thrives indoors is the Martha Washington (sometimes referred to as Lady Washington or Regal.) Geraniums can either be grown from seeds or cuttings from another geranium plant. Seeds may take longer to flower, but in late summer and early fall, they'll produce beautiful blossoms, rivalling the plants grown from cuttings. Regardless of which style of "birthing" you choose for your geraniums, care for them will remain the same.
Find a sunny spot to place your geraniums as they grow best in sunlight. Due to shortened days during winter months, this may prove difficult. As an alternative, a fluorescent light can provide the needed light. According to the University of Minnesota Extension, "Fluorescent lights can be used from 6 p.m. to 10 p.m. to supplement natural light." The lighting source should also be kept 10 to 12 inches from the plant.
Choose a clay or plastic pot with drain holes and a saucer beneath to catch water drainage. The drain holes will allow the water to seep out the bottom and away from the roots. A few minutes after watering, empty saucer to avoid having your geranium sit in water.
Use a good soil mix. Half soil and half peat works well. Fertilisation is only necessary during the growing process and an indoor fertiliser should be used in this instance.
Watch your watering. Geraniums will not do well if over-watered. Check the soil with your finger. If it is dry, add water until moist. If it feels cool and moist, do not water. It's better for the plant to be dry than saturated. Water the base of the plant only and avoid splashing the leaves to cut down on disease.
Keep the temperature down. Geraniums prefer a temperature around 12.8 degrees C at night and 18.3 degrees C during the day. If your plants are near the window, make sure there isn't a heat source beneath them like a radiator or heat vent. This will overheat your plant and dry it out. Cold draughty areas will also affect the health of your plants.
Prune your geraniums to encourage beautiful blossoms and to rid the plant of disease. Remove any leaves that have spots. According to the Indoor Gardening Guide, some common diseases for Geraniums are Black Leg, Leaf Spot, Gray Mold, Rust, Root Knot and Dropsy.