Geraniums grow slowly, so start from seed now for spring blooms. Mature plants will flower about 12 to 16 weeks after you sow seed.
To start geraniums from seed:
- Plant seeds 2 to 3 inches apart and 1/8 inch deep in a seed-starting mix.
- Cover the container with clear plastic and place in bright indirect light at about 75ºF. Keep soil moist but not soggy.
- When the first set of true leaves appears, transplant seedlings into individual containers filled with potting mix.
- Geranium seedlings do best with 12 to 16 hours of light a day. Fluorescent lights placed 4 to 6 inches above the plants work well.
- Water only when the soil is dry. Fertilize every week with a houseplant fertilizer at one-fourth its recommended strength.
- Harden off the plants by placing them outdoors for progressively longer periods of time. This could take seven to ten days.
- Plant geraniums outdoors when danger of frost has passed.