Lobelia: Sowing, planting and harvest calendar
How do you sow lobelia outdoors?
Choose seed labelled with its species. Lobelia erinus, often used seasonally, needs a sufficiently warm, frost-free period for outdoor sowing. Lobelia cardinalis is a perennial with different requirements: check timing and any preparation specified for your seed lot. Cold stratification should not be imposed on every seed in the genus.
Prepare a fine, clean, previously moistened surface in level garden soil or a container with drainage holes outdoors. Sow thinly, since the seeds are tiny and difficult to space individually. Light favours germination of erinus; cardinalis seed also requires light. Scatter seeds on the surface and press gently for contact without burying them beneath a layer of soil.
Keep the surface moist with gentle misting or a very fine spray that does not move the seeds. Protect against heavy rain, drying wind and excessive heat while retaining light. Emergence varies with temperature, seed freshness and preparation, so monitor it instead of expecting one fixed interval. Label the species and date. Thin crowded seedlings gently once they are developed enough to handle without damaging their neighbours.
When do lobelias flower?
