What are the easiest plants to grow from seed for beginners? Cosmos, Peas, Leaf Lettuce, Nasturtiums, and Marigolds top the list thanks to their forgiving nature and quick germination. Whether you’re starting seeds indoors in March or dreaming of a vibrant 2025 garden, these picks thrive with minimal fuss. Kate Van Schaik, Landscape Designer at Royal City Nursery (located between Guelph, Cambridge, Kitchener in Ontario) shares why these plants are foolproof, how to grow them successfully, and gives her pro-tips on how to avoid common pitfalls. Ready to dig in? Let’s Grow!
March might feel like winter’s last gasp, but it’s prime time to kickstart your garden indoors. Most annuals and veggies germinate best 6-8 weeks before the last frost (around early May in Royal City Nursery’s climate). Starting now means stronger plants and earlier blooms or harvests.
Pro Tip: Always check seed packets for “days to germination” and “indoor start” cues—our video on ‘How to Read a Seed Packet’ breaks it down step-by-step.
Seedlings are delicate, though—sun, warmth, and water can make or break them. Place trays in a south-facing window (60-70°F is ideal), rotate daily to prevent leaning, and use a mister to keep soil moist, not soggy. For extra protection, grab a humidity dome from our store—it’s a game-changer for germination rates.
Before transplanting outdoors in May, seedlings need to toughen up—a process called “hardening off.” Think of it like shedding winter layers: start with an hour outside on a mild day, then gradually increase exposure over 7-10 days. To mimic wind, gently brush seedlings with paper or use a low fan setting indoors. This builds sturdy stems ready for Royal City’s breezy springs. Watch Out: Skip this step, and you’ll risk leggy, weak plants—or worse, total collapse.
Why It’s Easy: Cosmos (Cosmos bipinnatus) germinate in 7-14 days and tolerate neglect like champs. These sun-loving annuals sprout daisy-like flowers in jewel tones (magenta, ruby) or soft pastels (pink, white) that sway cheerfully in summer breezes.
How to Grow: Sow ¼-inch deep in a Jiffy plug or seed tray in March. They’ll sprout fast in 65-75°F soil. Transplant after frost to full sun spots—they hit 3-5 feet tall, so give them space!
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Why It’s Easy: Peas (Pisum sativum) germinate in 7-10 days and grow fast, even in containers. Soaking seeds speeds things up—they’re ready to sprout when they sink (floaters are duds).
How to Grow: Soak seeds in room-temp water for 24 hours in a dark spot (a cupboard works). Plant 1-inch deep, arrow-end down (see the tiny white “radical” tip?), in trays or pots. Move to full sun or partial shade by mid-May—they’ll climb 2-6 feet with support. Water daily in summer heat.
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Why It’s Easy: Leaf lettuce and microgreens sprout in 3-7 days and thrive in cool conditions—perfect for windowsills or unheated porches. Tiny seeds mean shallow planting, so they’re low-effort.
How to Grow: Scatter seeds on moist soil (barely cover—1/8-inch max) in trays or shallow pots. Keep at 50-70°F with bright light. Snip microgreens at 1-2 inches (10-14 days); harvest lettuce leaves at 4-6 inches (30-45 days).
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Why It’s Easy: Nasturtiums (Tropaeolum majus) germinate in 7-12 days and grow anywhere—pots, beds, or trellises. Their peppery leaves and flowers add zing to meals.
How to Grow: Soak large seeds for 12 hours, then plant ½-inch deep in March. Move to full sun or light shade post-frost. Clump types hit 12-18 inches; climbers reach 6 feet.
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Why It’s Easy: Marigolds (Tagetes spp.) sprout in 5-10 days and shrug off pests with their pungent scent—skunks, rabbits, and nematodes hate them.
How to Grow: Sow ¼-inch deep in trays in March; they love 70-75°F for germination. Transplant to full sun in May—they range from 6-inch dwarfs to 3-foot giants.
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Success starts with the right gear. Swing by Royal City Nursery for:
These five plants—Cosmos, Peas, Lettuce, Nasturtiums, and Marigolds—are your ticket to gardening confidence in 2025. Start them indoors now, harden them off in May, and watch your yard (or windowsill) come alive. Got a favourite? Tag us on Instagram @royalcitynursery we’d love to see your sprouts! Still have questions? Our expert team is always available to answer any questions you may have.
About Kate Van Schaik
Kate Van Schaik (Bachelor of Arts & Sciences (B.A.S.) has been growing plants since she was 5 years old. This lifelong passion led to a career in horticulture, spending 15 years growing for a commercial nursery before joining the RCN team as a Landscape Designer in 2022. With a B.A.S. in Forest Science and Geography (University of Guelph), and post diplomas in Ecosystem Restoration (Niagara College) and Landscape Design (University of Guelph), Kate is uniquely qualified to create beautiful and inspiring landscapes that live in harmony with the environment around us.
About Royal City Nursery
Guelph, Ontario’s only third-generation, full-service garden centre! We specialize in creating custom outdoor living spaces and unique solutions for all your garden, landscape, and seasonal decorating needs! At our new greenhouse, located between Guelph and Cambridge, we are the garden centre of choice for discerning homeowners, landscapers, and designers.
