Foxgloves (Digitalis spp.) thrive in nutrient-rich, well-draining soil with a slightly acidic to neutral pH (6.0–7.0). As biennials or short-lived perennials, they require balanced nutrition to support vigorous foliage growth in their first year and prolific flowering in the second. Key nutrients include nitrogen (N) for leafy growth, phosphorus (P) for root and flower development, and potassium (K) for overall plant health. Micronutrients like calcium and magnesium also play vital roles in cellular function and chlorophyll production.
Organic fertilizers release nutrients slowly, improving soil structure and microbial activity. Ideal options for foxgloves include:
Well-rotted compost provides a balanced mix of macro- and micronutrients. Apply a 2–3 inch layer around the base in early spring, gently working it into the topsoil. This also enhances moisture retention.
Poultry or cow manure (aged 6+ months) is rich in nitrogen. Mix 1–2 inches into the planting bed before sowing or transplanting. Avoid fresh manure, as it can burn roots.
A phosphorus-rich option (11% P), bone meal promotes strong root systems and flower spikes. Apply 1–2 tablespoons per plant at planting time or early spring.
A fast-acting liquid fertilizer (5-2-2 NPK), fish emulsion supports leafy growth. Dilute as directed (typically 1–2 tablespoons per gallon) and apply every 3–4 weeks during active growth.
Synthetic fertilizers offer precise nutrient ratios and rapid availability. Use them cautiously to avoid over-fertilization, which can harm foxgloves' shallow roots.
A slow-release 10-10-10 NPK formula provides equal parts nitrogen, phosphorus, and potassium. Apply 1/4 cup per square foot in early spring, watering thoroughly afterward.
High-phosphorus formulas enhance flowering. Apply a 5-10-5 fertilizer at half strength when flower spikes begin forming, ensuring even distribution around the drip line.
For container-grown foxgloves, a diluted 20-20-20 solution (1/2 teaspoon per gallon) every 2–3 weeks ensures consistent nutrition. Avoid foliar feeding to prevent leaf burn.
Fertilize foxgloves in early spring as new growth emerges and again just before flowering. Avoid late-season feeding, as it may reduce winter hardiness.
Conduct a soil test every 2–3 years to adjust nutrient ratios. Foxgloves are sensitive to excessive nitrogen, which can cause leggy growth with fewer flowers.
Pair fertilization with organic mulch (e.g., shredded leaves) to regulate soil temperature and reduce nutrient leaching. Maintain a 2-inch layer, keeping it away from stems to prevent rot.
