Originally from Mexico, zinnias have become an annual favorite for gardeners wanting to spruce up their gardens with color. Zinnias are in the same family as daisies (Compositae). They are a warm season annual and are easy to grow from seed or container plants. Containers filled with colorful zinnias, are sure to brighten up any spot in your landscape. Once established, zinnias will require very little tending to. They are perfect for novice gardeners, as they can withstand a wide range of soil conditions and neglect.
Select a container to grow the zinnias in that has drain holes in the bottom. The size and shape of the container will not matter. Everything from regular planting pots (round or rectangular), hanging baskets, window boxes and even wooden barrels, can be used to plant the zinnias in.
Consider the container's size, when figuring out how many plants you will need to fill it. Zinnias require good air circulation between each other. Space each plant six to ten inches apart. This will give you an idea of how many plants will be required.
Select a type of zinnia that is best suited for the size of the container. Zinnias come in two sizes: tall, which grow three to four feet in height and dwarf, which grows eight to 14 inches in height. The taller the zinnia, the larger the container should be.
Fill the container two-thirds of the way full, with a light potting mix that contains organic matter and peat moss. This will allow for proper drainage, which zinnias require. Though tolerant to many soil types, zinnias will not live if planted in a potting medium that remains soggy when watered.
Situate your zinnia plants on top of the soil the way they look best to you. If dealing with several different varieties or colors, space them out appropriately. Place the taller plants in the center. Space the shorter plants to its sides.
Dig a small hole into the container that is large enough for the plants root ball to fit into it. Repeat this step for the remaining plants going into the container.
Fill in the remainder of the container with potting mix. Use your hand to firm the soil up around the base of the plants.
Water the container until it flows out of the drain hole in the bottom. Test the soil by sticking your finger into it. If it feels dry to the touch, give the container water. Zinnias are relatively drought-tolerant, but regular watering will help the plant thrive and produce more blooms.
Situate the container in an area that receives full sunlight or partial sun. Zinnias grow best in warm locations that receive sunshine. Make sure the zinnias receive at least 4 hours of sunlight each day.
Fertilize the zinnias with a 20-20-20 water-soluble fertilizer, once every two weeks. They are light feeders, but a periodic dose of fertilizer will help them retain their green foliage and produce more blooms.