Growing a Sunflower House: Planting Tall Sunflowers in a Square
The short answer
Mark a square in a sunny spot, clear a narrow strip along the outline and sow tall sunflowers in one or more rows. Leave an opening for a door. Water often so the soil stays moist while plants are young and mulch once they have a few sets of leaves. Depending on variety, flowers appear about 7 to 12 weeks after sowing.
A sunflower house is a garden room made by sowing tall sunflowers along the outline of a square, leaving one gap as a doorway. As the plants grow, they form leafy walls with flowers overhead. Extension guides recommend full sun, well drained soil and sowing after frost. Choose tall varieties for the walls.
What is a sunflower house?
It’s a play space built from plants. KidsGardening describes sowing sunflowers along the outline of a house so the plants form the walls, with at least one unplanted opening as a doorway. Kids can furnish it with a stone doorstop or a small table and chairs and explore it during outdoor time.
If your sunflower house sits near other crops, what roles do bees play in outdoor cannabis explains how bees move through a mixed garden.
How do you lay out a sunflower house?
KidsGardening suggests a 4 by 4 foot square as a good starting size, though the house can be any size or shape. Sprinkle flour on the ground to mark the outline. Clear weeds and grass in a strip 6 to 12 inches wide along the line to form a planting bed. Sow in a single row or in several rows for thicker walls.
Pick the site carefully. University of Minnesota Extension recommends full sun and a soil pH of 6.0 to 6.8. University of Missouri Extension notes that sunflowers need more than six hours of sun. For more on choosing spots in a bed, see planning an outdoor cannabis garden layout.
Which sunflowers make good walls?
Height decides the look. KidsGardening notes that sunflowers range from about two feet to 15 feet tall. University of Minnesota Extension groups them by size.
| Type | Role | Notes |
|---|---|---|
| Dwarf | Low border or window | Three feet or less (UMN) |
| Semi dwarf | Short walls | Three to eight feet, usually no staking needed (UMN) |
| Giant | Tall walls | Eight feet and up, sometimes need staking. Examples: Mammoth Russian, American Giant (UMN) |
| Very tall | Corners and tall walls | Stake or brace varieties over ten feet (University of Missouri) |
Sources: University of Minnesota Extension, University of Missouri Extension.
Spacing changes with size. UMN suggests about six inches for two to five foot varieties, at least one foot for taller ones and two feet for giants.
How to: step by step
- Choose a spot with full sun.
- Mark a square and leave a doorway.
- Clear a narrow planting strip along the lines.
- Sow tall sunflower seeds about one inch deep after the danger of frost has passed.
- Thin seedlings to the packet spacing.
- Water young plants and mulch the strip.
Seeds usually sprout in 7 to 10 days, according to both UMN and University of Missouri Extension. KidsGardening notes that older plants grow deep roots and handle drier conditions. Mulch stops weeds and grass from competing, and mulch for cannabis covers common materials.
Troubleshooting
Gaps in the walls: poor germination. Resow early so the new plants catch up.
Leaning stalks: wind or shade. Stake tall plants. University of Missouri Extension recommends staking or bracing varieties over ten feet.
Short walls: a dwarf variety. Pick tall types like Mammoth Russian next time.
A summer room for kids
A sunflower house turns a patch of soil into a hideout and a seed harvest. The Kind Seed Co blog has more projects like this in the garden layout and care section.
Sources
- Plant a sunflower house, KidsGardening
- Growing sunflowers in home gardens, University of Minnesota Extension
- Sunflowers (YM102), University of Missouri Extension
FAQ
How big should a sunflower house be?
Any size works, but KidsGardening suggests starting with an area of four feet by four feet. That's big enough for a child to sit inside and small enough to plant and water easily. Mark the outline with flour, clear a strip along the edge and leave a gap for the door.
How long do sunflowers take to bloom?
That depends on variety. KidsGardening says plants begin to flower about 7 to 12 weeks after sowing. University of Missouri Extension gives a range of 70 to 120 days. Check the seed packet for the days listed for your variety.
Can you add a roof?
The sources here don't describe building a roof. Tall varieties grow well above head height, so their flower heads hang over the walls on their own. University of Minnesota Extension notes that giant types reach eight feet and up, which is plenty of height for a leafy ceiling of blooms.
What happens to the seeds at the end?
Harvest them for snacks or the birds. KidsGardening suggests bagging ripe heads in brown paper bags tied around the stem, which catches falling seeds and lets air move. Seeds are ready when the back of the head turns brown and dry and most of the petals have dropped.
How fast do sunflower seeds sprout?
Seeds usually sprout in 7 to 10 days, according to both University of Minnesota Extension and University of Missouri Extension.
