Six Seeds Ideal for Sowing in March to Ensure Summer Blooms
Elevate your garden game for vibrant summer blooms by initiating your perennials indoors. Set the stage for flourishing outdoor plants by tending to your seedlings as early as late February or early March, ahead of the April last frost. Here's your guide to nurturing these seven perennials that can be seeded indoors now, all set to grace your garden during the warmer months.
Certified Garden Coach Sara Rubens, Founder of Seed to Sanctuary, and Lawn Care Specialist Chrissie Handley from Online Turf, share their insights for growing these stunning plants.
1. Black-Eyed Susans (Rudbeckia hirta)
Discover the delight of classic, cheerful yellow flowers with dark centers, boasting a year-round return, as suggested by certified garden coach Sara Rubens. Black-eyed Susans are known for their simplicity and ease of cultivation.
Sow the seeds 10 weeks prior to the last frost, and plant them 1⁄4 inch deep in seed trays. Watch for germination within 1 to 3 weeks.
- Hardiness Zone: USDA zones 3-9
- Light: Full sun
- Water: Deeply water seedlings once a week
- Soil: Neutral or acidic, well-draining and moist
2. Coneflowers (Echinacea)
Brighten up your garden with these summer blooms, featuring daisy-like flowers in various colors. Coneflowers are perfect for bringing cheer and pops of color to your garden.
To ensure successful germination, position the seeds near a consistent light source, while keeping them consistently moist.
- Hardiness Zone: USDA zones 3-9
- Light: Full, partial sun
- Water: At least once a week until established
- Soil: Neutral or acidic, well-draining
3. Tickseed (Coreopsis)
Enjoy the long-blooming spectacle of bright oranges, yellows, or reds by incorporating tickseed into your garden. This sun-loving plant thrives in sandy soil and requires minimal attention.
To cultivate tickseed, start 6 to 8 weeks before the last frost and plant seeds 1⁄2 inch deep. Keep seedlings moist in a sunny window while preparing them for outdoor planting.
- Hardiness Zone: USDA zones 2-11
- Light: Full sun
- Water: Regularly water seedlings to prevent soil drying out
- Soil: Neutral or acidic, well-draining and sandy
4. Lavender (Lavendula spp.)
Invite striking purple flowers, grey-green leaves, and an enchanting scent to your garden by planting lavender. Seed lavender indoors about 10 to 12 weeks before the last frost or according to the seed packet guidelines.
Lavender seeds need shallow planting, close to the surface, with a light covering of soil. Keep soil moist with gentle misting and avoid overwatering to promote proper germination.
- Hardiness Zone: USDA zones 5-9
- Light: Full sun
- Water: Mist seedlings daily to maintain moisture
- Soil: Alkaline, dry, well-draining
5. Delphiniums (Larkspur)
Delight in colorful spring and early summer blooms with delphiniums. This tall flowering plant, known as larkspur, is available in a wide range of hues, from gentle whites and pinks to dynamic blue and lavender tints.
Starting delphiniums indoors is ideal, as they prefer a cooler temperature for germination. Plant them in a cool, dark area, then gradually introduce them to a lighter environment once they sprout.
- Hardiness Zone: USDA zones 3-9
- Light: Full sun to partial shade
- Water: Water seeds deeply once or twice a week
- Soil: Neutral, moist, loamy, well-draining
6. Baby's Breath (Gypsophila spp.)
This delicate, white-flowered ground cover is an excellent addition to any garden. Baby's breath also self-sows once it is well established, making it a lovely and consistent source of summer blooms.
To grow baby's breath indoors, start 6 to 8 weeks before the last frost, and lightly cover seeds with about 1⁄4 inch of soil. Keep it moist, watering at least once a week during the seedling phase.
- Hardiness Zone: USDA zones 3-9
- Light: Full sun
- Water: Moisten soil regularly to prevent drying out
- Soil: Neutral or alkaline, well-draining
- RealSimple advises starting delphinium seeds indoors, as this tall flowering plant, known as larkspur, prefers a cooler temperature for germination.
- Placing delphinium seeds in a cool, dark area and gradually introducing them to a lighter environment once they sprout can help elevate your outdoor gardening experience by providing colorful spring and early summer blooms.
- home gardeners can also benefit from tending to their seedlings of perennials like delphiniums, as early as late February or early March, ahead of the April last frost.
- Outdoor gardening enthusiasts may be surprised to learn that delphiniums, known for their vibrant blues and purples, are part of the perennials that can be seeded indoors now, ensuring a gorgeous display during the warmer months.
