Penhill Watermelon Dahlia Seeds - Dahlia, 40 seeds

Quantity: 40 Seeds / pack

Penhill Watermelon is a giant dinnerplate dahlia type, celebrated for its huge watermelon-pink blooms. Growing dahlias from seed is an adventure: every seedling is genetically unique, so expect a range of bloom colors, sizes, and forms rather than exact copies of the named parent — many gardeners find the surprises the best part.

Seed-grown dahlias bloom in their first summer and form small tubers by fall, which can be lifted and stored to grow on the favorites next year.

Why choose our seeds?

• Dinnerplate-type dahlia seed — expect large, showy blooms with delightful variation
• Flowers in the first summer from an early indoor sowing
• Seed-grown plants form tubers you can lift, store, and replant

How to grow Penhill Watermelon Dahlia seeds

Choose Your Planting Method

• Indoors: Start indoors 6 to 8 weeks before the last frost — the surest route to first-year blooms.
• Outdoors: Sow outdoors after all frost danger and warm soil, though the season will be shorter.

Prepare Your Materials

• Seed-starting trays or pots (if indoors)
• Well-draining potting mix
• Spray bottle for misting

Sowing the Seeds

• Sow shallowly, about 1/16 inch deep, in moist seed mix.
• Keep evenly moist and warm until sprouted.

Provide the Right Conditions

• Light: Bright light once germinated; full sun for growing plants.
• Temperature: 65–70°F (18–21°C).
• Humidity: A cover helps hold steady moisture until germination.

Germination

• Germination in 7 to 21 days.
• Grow seedlings stocky in bright light and cooler air.

Transplanting

• Transplant after all danger of frost; harden off first. Pinch the growing tip once plants have 3 to 4 leaf pairs to encourage branching.
• Spacing: About 12 inches apart.

Care Tips

• Sun: Full sun — at least 6 hours daily for the biggest blooms.
• Water: Regular, even moisture with good drainage; mulch helps hold soil moisture.
• Fertilizer: Feed every few weeks with a low-nitrogen fertilizer once buds form.
• Deadhead faded blooms to keep flowers coming; stake tall plants. In fall, lift tubers after frost blackens the foliage and store cool and dry for spring.

Bloom Time:

Blooms from midsummer until frost.