The common foxglove, Digitalis purpurea, is a popular addition to gardens, known for its majestic, tall spires of tubular flowers. These striking blooms provide vertical interest and are highly attractive to pollinators such as bumblebees. Successfully growing foxglove from seed depends on understanding its life cycle and selecting the correct timing for sowing. This guide details the optimal methods and windows for planting foxglove seeds.
Understanding Foxglove’s Life Cycle and Optimal Timing
Most varieties of foxglove are biennials, meaning their life cycle spans two growing seasons before they flower, set seed, and die. The first year is dedicated to vegetative growth, establishing a low-lying rosette of leaves and a strong root system. The plant must undergo a period of cold temperatures, known as vernalization, before it can trigger flowering in its second year.
This biennial nature dictates two primary windows for sowing seeds to ensure blooms the following spring or summer. The first is a late summer or early fall sowing, allowing the plant to establish its rosette before winter dormancy. The second is a late winter or very early spring start indoors, giving the plant a head start. The choice between these timings is influenced by your local climate and the date of your first or last frost.
Sowing Seeds Directly Outdoors
Direct sowing outdoors is the most natural method and is best performed in late summer, typically July through September, depending on the region’s climate. This timing allows the developing seedling to form a robust root system and a substantial rosette of leaves before deep frost arrives. This ensures the plant is well-established to survive winter and flower the following year.
The seeds need a site with partial shade and well-drained soil rich in organic matter, mimicking its native woodland edge habitat. After preparing the soil surface, the minute foxglove seeds must be surface-sown. They should be scattered lightly over the soil and pressed gently into the surface. Covering the seeds with soil must be avoided because Digitalis seeds require light for successful germination.
Keep the seedbed consistently moist throughout the germination period, which typically takes seven to twenty-one days. Once the seedlings have developed their second set of true leaves, they should be thinned out. Thinning involves removing weaker seedlings so the remaining plants are spaced approximately 18 to 24 inches apart.
Starting Seeds Indoors Early
Starting foxglove seeds indoors offers a reliable alternative, particularly in regions with short growing seasons or severe winters. This method is typically done in late winter or very early spring, about 10 to 12 weeks before the last expected frost date. Using a sterile seed-starting mix in trays or small pots helps prevent fungal issues that can damage young seedlings.
Similar to outdoor sowing, the tiny seeds should be surface-sown and not covered with soil, as they rely on light for germination. Place the trays in a warm environment, ideally 60°F to 65°F, and maintain consistent moisture by watering from below. Once the seedlings emerge, they need bright light to prevent them from becoming spindly, which is best achieved with a dedicated grow light positioned just inches above the foliage for 14 hours a day.
When the risk of frost has passed, the seedlings must undergo “hardening off” before transplanting them into the garden. This involves gradually exposing the young plants to outdoor conditions, including direct sun, wind, and cooler temperatures, over seven to ten days. After this transition, the seedlings are ready to be planted into their final garden location.
Post-Sowing Care and First-Year Expectations
Regardless of whether the seeds were sown directly or started indoors, initial care focuses on establishing strong, healthy plants. The soil must be kept consistently moist but not waterlogged, as young seedlings are susceptible to drying out or fungal diseases. A light application of a water-soluble fertilizer can be provided once the seedlings have developed their first true leaves, about three to four weeks after germination.
Pest and disease management is generally simple, though slugs and snails may target the tender new foliage. It is important to manage expectations during the first year of growth, as the plant will not produce its signature flower spires. The entire first season is dedicated to developing the basal rosette of leaves, which must reach a sufficient size to store the energy required to survive winter and initiate flowering the following year.