How to Germinate Northern Catalpa Seeds
- 1). Prepare the container in which you will germinate the northern catalpa seeds. For just a few seeds, a nursery pot is ideal. For larger quantities of seeds, use a nursery flat. If you are using an old container, clean all the soil out of it, scrub it in hot, soapy water and rinse it thoroughly. Sterilize the container by soaking it for 30 minutes in a solution of 1-part household bleach to 5-parts of water. Rinse well after soaking.
- 2). Fill the container with a peat-moss based seed starting mix. Water the medium until it is soaked and set the container aside until the medium drains to barely moist.
- 3). Place the seeds on the surface of the planting medium. Northern catalpa seeds require light to germinate, so don't cover them with the seed starting medium.
- 4). Spray the seeds with water after sowing and periodically during germination to keep them consistently moist.
- 5). Set the container in an area that receives indirect sunlight, on top of a heat mat set to 68 degrees Fahrenheit.
- 6). Place a fan, set to low speed, next to or over the container to blow air across the surface of the medium. Don't place the fan so close that it blows the seeds or medium – just close enough to lightly circulate the air. Northern catalpa seeds are susceptible to fungal diseases that may kill them and good air circulation helps avoid that. Northern catalpa seeds typically germinate within 12 days.
Source...