Sunflower House

1.   In the spring (once the ground is warm enough to work), stake out a 6-foot square in a sunny spot. Using a spading fork, loosen and turn over the soil in a 1-foot-wide path along the perimeter of the square where the sunflowers will be planted. Leave a few feet on the north side unturned for an entryway. Because sunflowers require a fair amount of nutrients, mix compost or aged manure into the soil (about a 50-50 mix, compost to soil).

2.   Once night temperatures are 50 degrees or above (generally by mid- to late May in the northern states, earlier in southern locales), it's safe to plant your sunflowers. Hans recommends the Mammoth Grey Stripe, which has a sturdy stem and large head and grows up to 12 feet tall. When you're working with kids, Hans suggests starting seeds in easy-to-handle peat pots, biodegradable containers made of moss and wood fibers. Plant 2 seeds in each of 24 pots and set them in a sunny, sheltered spot. Keep the soil moist but not too wet. Once the seedlings grow several inches tall, snip back the smaller of the two. Then plant the seedlings, pots and all, 1 foot apart in the ground and water them well. Or plant your seeds directly in the ground, placing 2 seeds in each hole and spacing the holes 1 foot apart. When the plants are 4 to 8 inches tall, snip back the weaker of each pair.

3.   As your sunflowers grow, water and weed them as needed. If you spread mulch around them and the soil is fairly rich, they'll require a good watering only when it hasn't rained for a week or so. Otherwise, you may have to water more often so the roots will grow enough to support the tall plants. For more vibrant growth, Hans advises spraying the leaves weekly with liquid kelp (a nutrient-rich solution sold at gardening stores).

4.   When the sunflowers are about 4 feet tall, you can plant some annual flowers between them to add color to the house.

5.   When the sunflowers are 6 to 7 feet tall, it's time to start shaping the roof. To do this, gently tie baling twine (sold at garden supply stores) around a flower on one side of the house, securing it to the stem about 1 foot below the head (a task that may call for a stepladder). Slowly pull the plant toward the flower opposite it and loop the free end of the twine around that flower's stem. Slowly pull the two plants together until the tops meet and knot the twine to hold them in place. Pair up the other flowers in this way until the roof is complete. Over the next few weeks, as the plants continue to grow, you can adjust the twine ties as needed.