Verbena seeds are difficult to germinate, so to get the best results, start the seeds indoors. Planting the seeds in starting medium, keeping them in the dark prior to germination, and keeping the soil moist will improve germination rates. Once the verbena are ready to transplant outside, they are generally not fussy and grow well in sunny, well-drained soil.
The most important tip to planting verbena seeds is to properly prepare the soil. Fill potting containers with sterile planting mix. This will help prevent mildew and disease from damaging the seeds before they germinate. Use fresh seeds, as seeds that are even one year old will have a dramatically reduced germination rate.
Start the seeds about two to three months before the frost free date. Do not start the seeds earlier than this, and try to hold them inside. Once the plants are well-established, they need to be transplanted outside. Keeping them inside too long will result in weak, spindly plants that may not recover once transplanted.
Place the seeds in the pots, covering them with soil. Because of the poor germination rate of verbena seeds, plant several seeds in each container. They can be thinned later if necessary. Verbena seeds germinate better in the dark, so make sure the seeds are covered thoroughly.
Use a spray bottle to mist the soil until it is moist. Verbena germinate well at comfortable room temperatures. Expect the seeds to push through the soil in two to three weeks.
Once the verbena seeds have sprouted, use a pair of sharp scissors to thin the plants. Verbena require good air circulation to thrive. Continue to keep the soil moist, allowing the soil to dry out once the seeds have sprouted can kill the plant.
About two weeks before the weather warms enough to transplant the verbena plants outside, it is time to begin the hardening off process. Carry the plants outside for a few hours each day, on days that are warm and calm. Cold, windy weather will kill the plants at this point. The hardening off process slows the growth of the plant, but also toughens it up. The stem and leaves will develop a thicker texture as the plants prepare for life outdoors.
Starting verbena seeds is an inexpensive way to add color to the garden. Verbena are easy to care for, non-invasive, and attract wildlife. They are considered short-lived perennials, although many people grow them as annuals. The bloom early in their first year, and have a long flowering season.