Planting lush, colorful flowers adds beauty and decoration to any yard, but isn't always an option for people who live in cold, rainy zones. Gardeners in harsher zones often turn to indoor and greenhouse gardening to grow and protect their flowers, or to grow flowers that don't adhere to the natural temperature of the region. To do so, though, it's important to choose flowers and seeds that grow well in an enclosed and controlled environment.
Nasturtiums and their seeds prefer warm, dry conditions, so if you live in a cooler climate, plant them in a greenhouse to control the environment. Plant nasturtium seeds in quick-draining soil, at a spacing of 10 to 12 inches and 1/2 inch deep. Since these are vining plants, consider using a raised bed to give them space to grow and trail over the wall. Put nasturtiums in the sun and expect sprouting in seven to eight days. Nasturtiums bloom in various shades of red, pink and orange, with edible shoots, leaves and blossoms.
Sweet pea seeds require fall planting and do well in areas that have mild winters. In colder regions, it's a good idea to sew these seeds in flower beds and shelter them through the winter in a greenhouse. Nick sweet pea seeds with a sharp knife to open the outer husk and make it easier for the seeds to germinate, then plant them in a mixture of half quick-draining soil and half organic compost or well-aged manure. Draw a toothpick through the soil to produce a 1-inch deep furrow, and plant the seeds 2 to 3 inches apart. Sweet peas bloom in delicate shades of pink, purple and white.
According to WildflowerInformation.org, gloriosa daisies descend from black-eyed Susans and display the same distinct coloration and growing habits. These daisies need full sun and plenty of warmth, and live for several seasons. Their lifespan means that they need winter protection in colder areas, via greenhouse or other indoor environments. Sew the seeds in beds that hold fertile, quick-draining soil and put them in full sun. Look for full blooming two years after germination.
Although many people know sunflower seeds best as snacks, these seeds are highly successful at doing what they're designed for: starting new sunflower plants. Start sunflowers in pots or flower beds for easy transfer within the greenhouse, and use quick-draining soil mixed with peat as a foundation. Push the seeds 1 inch deep in the soil and give them at least 6 inches of space for growth. Keep sunflowers in full sun and plant the warm-weather plants year round inside a greenhouse.