Growing Sunflower Indoors — Complete Guide
Yes, Sunflower can be grown indoors. Here's everything you need to know: container size, light requirements, watering schedule, and how to avoid the most common mistakes.
Sunflower Indoors — At a Glance
Container Size for Indoor Sunflower
Recommended: 12–16 inch pot
For indoor sunflowers, select dwarf varieties that stay under 24 inches — 'Elf', 'Little Becka', or 'Teddy Bear' are ideal. Standard sunflowers grow 4–8 feet and are impractical indoors. A 12-inch pot suits dwarf varieties; use a 14–16 inch pot for larger dwarf types.
Light Requirements
Hours of Light Needed
16 hours
per day, consistently
Grow Light Recommendation
High-output LED grow light (at least 60W equivalent) for 16 hours — sunflowers are among the most light-demanding plants you can grow. Without very strong grow lights, indoor sunflowers will lean and struggle to flower. Position lights 8–12 inches above the plant as it grows.
Watering and Humidity
Ideal Humidity: 40–60%
Sunflowers are drought-tolerant and tolerate average humidity. More important than humidity is air circulation — stagnant air encourages mold on the large flower heads.
Ideal Temperature: 65–85°F (18–29°C)
Keep away from cold drafts (air conditioning, windows in winter) and excessive heat sources (heaters, ovens). Consistent temperature produces the most vigorous growth.
How to Grow Sunflower Indoors: Step by Step
Select a dwarf variety
Choose 'Elf' (16 inches), 'Little Becka' (12–15 inches), or 'Teddy Bear' (18–24 inches). These produce beautiful flowers on compact plants suited to indoor pots.
Sow directly in final container
Sunflowers dislike transplanting. Sow 2–3 seeds 1 inch deep in a 12–16 inch pot. Thin to the strongest seedling after germination. Germination takes 7–10 days.
Set up your strongest grow lights
Position high-output LED lights 8–12 inches above the seedlings for 16 hours daily. Raise the light as the plant grows. Rotate the pot every day to prevent leaning.
Water consistently and deeply
Water when the top inch of soil is dry. Water deeply until it runs from the drainage holes. Empty the saucer after 30 minutes.
Enjoy the flowers
Dwarf sunflowers typically flower in 60–70 days indoors. Once the head opens, the plant is done — sunflowers are annuals. Collect seeds from the dried head for replanting.
Common Indoor Sunflower Problems & Fixes
Extreme leaning toward light source
Cause
Phototropism — all sunflowers grow toward light, but worse with insufficient total light
Fix
Rotate pot every day; use grow lights that cover the entire plant; increase light intensity
Failure to flower or budding very late
Cause
Insufficient light
Fix
Upgrade to stronger grow lights; ensure 16 hours; dwarf varieties flower more reliably indoors than standard types
Powdery mildew on leaves
Cause
Poor air circulation, especially around the large leaf canopy
Fix
Use a small fan near the plant; improve ventilation
Frequently Asked Questions
Can I grow Sunflower indoors?
Yes, Sunflower can be grown indoors with the right conditions. You'll need 16 hours of Maximum light — sunflowers' most critical requirement, a 12–16 inch pot, and temperatures of 65–85°F (18–29°C). The difficulty level for growing Sunflower indoors is Moderate.
How much light does indoor Sunflower need?
Indoor Sunflower needs 16 hours of light per day. High-output LED grow light (at least 60W equivalent) for 16 hours — sunflowers are among the most light-demanding plants you can grow. Without very strong grow lights, indoor sunflowers will lean and struggle to flower. Position lights 8–12 inches above the plant as it grows.
What size container does indoor Sunflower need?
For indoor sunflowers, select dwarf varieties that stay under 24 inches — 'Elf', 'Little Becka', or 'Teddy Bear' are ideal. Standard sunflowers grow 4–8 feet and are impractical indoors. A 12-inch pot suits dwarf varieties; use a 14–16 inch pot for larger dwarf types.
Best Cities for Growing Sunflower Outdoors
If you're growing Sunflower indoors year-round, check the outdoor calendar for your city — you may be able to grow it outside during warmer months too.
Growing Sunflower Outdoors Too?
Find the best planting times for Sunflower in your city with our climate-based calendar.