Dahlia plants are an excellent addition to any garden or landscape, and are easy to grow. Growing your dahlia plants from seed is easy and will offer more satisfaction than purchasing a seedling from a garden center or nursery. So, here is a handy step by step guide to help you get started.
Step 1 – Germination Tray
Put a layer of potting soil into a flat tray. Purchase fresh potting soil to ensure is no insect infestation or mold present in the soil. Firm up the layer, but don’t make it too firm.
Step 2 – Sprinkle the Seeds
Sprinkle the seeds over the surface of the potting soil. Finish off by covering the seeds with about half an inch of additional potting soil.
Step 3 – Water the Tray
You don’t want the soil to become soaked - so water very carefully. Use A fine spray so that you can accurately judge how damp the soil is. When germinating dahlia seeds, damp soil is essential so check it regularly and spray when the top soil is dry.
Step 4 – Cover the Tray
Cover the tray with transparent film to protect the seeds from draft and to keep the soil moist.
Step 5 – Keep the Seeds Warm
Dahlia seeds germinate best at a temperature of around 75ºF. So, consider using a heating mat to help maintain a constant temperature.
Step 6 – Remove Film when Seeds Sprout
Most dahlia seeds will sprout within seven to twelve days, but they will not all sprout together. As soon a sprouting begins - remove the plastic film.
Step 7 – Pot the Seedlings
When the seedlings are about three inches tall, remove them and put into individual pots. Use the same potting soil in the pots, but mix the potting soil 2:1 with garden sand. It can be very beneficial to the plants if you use pots that can be planted directly into the soil when the time comes. This will avoid root shock to the plant and lead to healthier dahlia plants. Once the seedlings are potted, they can be grown in slightly lower temperatures.
Step 8 – Watering the Seedlings
Keep the pots in a bright and cool location while they continue to grow. The soil in the pots should be carefully controlled so that it does not dry out and does not get too wet.
Step 9 – Take the Seedlings Outside
After about five weeks, the plants should be mature enough to be planted outside. Before you do this, take the young seedlings outside during the day time so they can become accustomed to the outdoor weather. If you have a cold frame, you can store the seedlings there overnight rather than bringing them back indoors. If there is a even a hint of a coming frost, bring them indoors because they will still be very vulnerable at this point.
Step 10 – Transplant
Transplant the seedlings into a well drained and sunny location. They will cope with a degree of shade, but really thrive in direct sunlight. For the first two or three weeks following the transplantation, continue to water the seedlings on a daily basis.