Growing loofah in Canada is possible by starting seeds indoors 4-6 weeks before the last frost, using a heat mat for germination, and providing a long, hot growing season with plenty of sun. Transplant hardened-off seedlings outdoors after the risk of frost has passed, ensuring they are planted in a sunny spot with a sturdy trellis or fence for the vines to climb. 
There is a ton of information online, to guarantee a successful harvest.
Sponge gourd (Luffa cylindrica) is a vigorous, vining plant in the cucumber family, grown for both its edible young fruit and its fibrous, sponge-like interior when mature. Also known as luffa or dishcloth gourd, it produces yellow flowers and requires a long, hot growing season with strong support for its vines. The mature, dried gourd's fibrous network is used for natural sponges, while the young, tender fruit is used in cooking, particularly in Asian cuisine. 
Plant characteristics
Type: Annual climbing vine.
Family: Cucurbitaceae (gourd family).
Flowers: Bright yellow, with male and female flowers on the same plant.
Growth: Vines can grow very long (up to 15m) and need sturdy support like a trellis or fence. 
Uses
Culinary: Young, immature gourds (4-8 inches long) are edible, with a mild, slightly sweet taste, often cooked in stir-fries and soups. 
Sponges: Mature, dried gourds are processed to create natural, fibrous sponges for bathing, scrubbing dishes, and crafts. 
Growing conditions
Climate: Thrives in warm, humid climates with a long growing season.
Sun: Requires full sun.
Soil: Prefers well-draining, fertile soil.
Planting: Sow seeds outdoors after the last frost, providing support for the vines. 
Harvesting
For eating: Harvest when young and tender (around 4-8 inches long). 
For sponges: Leave on the vine until fully mature and dry, just before the first frost. The skin should be dry and brown, and the gourd should feel light. 
13 seeds per pack