Plant your cutting flowers in rows spaced 2 to 3 feet apart to allow room for walking between the rows and harvesting fresh-cut flowers. Because cutting gardens are not designed for display, several varieties can be planted in the same plot without regard for color coordination.
Space the flowers closer together than the recommended row spacing; this will encourage taller stems. For example, planting cosmos (Cosmos bipinnatus) 1 foot apart, instead of the recommended 2 feet, encourages the plant to grow upward and results in longer stems. According to Dr. Leonard Perry, extension professor at the University of Vermont, close spacing causes flower plants to produce taller stems, but it also causes reduced bloom size.
Water flowers following their recommended rates. Typically, this means 1 inch of rain per week or supplemental watering whenever the soil feels dry 1-inch below the surface. Soak the soil to a depth of 6 inches and water again when the soil dries.
Apply water-soluble fertilizer designed for flowering plants that you have mixed to a rate of 1 tablespoon per gallon of water, unless your product dictates otherwise. Apply every one to two weeks while the plants are actively growing.