Plan the perfect garden with our interactive tool →

How to Plant Zinnia

The zinnia is considered a tender annual and is indigenous to Mexico. They are a member of the Asteraceae family of plants. They are erect-growing, profusely blooming flowers which can grow to varying heights of 3 to 36 inches, depending on the variety. The colors of zinnias range from white, orange, various shades of pink, yellows and reds.

Planting Zinna Seeds Indoors

Purchase zinnia seeds.

To get an early start on the growing season for your zinnias, start indoors four to six weeks before spring.

Fill up your peat pots or planting cells with the potting mix. Saturate the potting mix with water, but do not soak. Be extra cautious when watering the peat pots; you don't want to get the peat pots so drenched with water that they begin to disintegrate. Just moisten the soil in the peat pots using a mister or plant sprayer.

Place two zinnia seeds into each planting cell or peat pot, press gently into the soil and cover with approximately 1/2 inch of the potting mix. Water each with your plant mister until the soil is lightly moistened.

Place your zinnias in an area that will receive plenty of warmth (65 to 70 degrees Fahrenheit) and light--eight to 10 hours of light per day, preferably natural sunlight.

Keep your zinnia seeds moistened, check on them every day or two. Germination time for zinnias is typically seven to 10 days.

Once your zinnia seedlings reach about 2 1/2 inches to 3 inches in height, decide where you want to plant them in your flower garden.

Turn over the soil with your shovel or garden fork in the area we want to plant your zinnias. Professor Leonard Perry of the University of Vermont recommends working in 2 or 3 inches of compost or peat moss while you're turning over the soil to help improve soil fertility and drainage for your zinnias.

Rake the area smooth and level, removing any weeds, rocks or sticks which might interfere with the growth of your zinnias.

Dig holes for your zinnias seedlings that are spaced 10- to 12-inches apart and are slightly larger than the receptacles. Each hole should be watered, but allow the water to drain off before planting your zinnia seedlings.

To remove a zinnia from a planting cell, simply push up from the bottom with your index finger or thumb until the plant is free and gently remove. Don't remove the zinnia seedlings from the peat pots; the peat will disintegrate after several waterings in the ground. Place a zinnia seedling into one of the freshly dug holes, level the base of the stem with the surrounding soil. Fill the hole with garden soil. Water each seedling carefully, do not get the stems or leaves wet since zinnias are prone to mildew. Place a garden stake next to each one of your seedlings to help offer them support as they grow.

Planting Zinnia Seeds Outdoors

Sowing zinnia seeds directly into your garden should be done when the temperatures are above 50 degrees Fahrenheit, both during the daytime and nighttime hours. Keep in mind that zinnias are hot weather plants and some varieties can reach heights of 3 feet. So take these factors into consideration when deciding where you want to plant your zinnia seeds.

Turn over the soil with your shovel or garden fork in the area we want to plant your zinnias. Work in 2 or 3 inches of compost or peat moss as directed in step 8 above.

Make sure to remove any rocks, weeds or sticks as you turn over the soil.

Dig rows which are set at 12 inches apart. Place two to three zinnia seeds approximately 3 inches apart, and cover with no more than a 1/2 inch of garden soil. Mist the seeded area until the soil is well watered. Place planting stakes around the perimeter of the area you seeded, so you will know where you should water.

Check on the seeded area every day or two. Keep the area lightly moistened.

Once your zinnias have sprouted (in approximately seven to 10 days) and grown to about 3 inches in height, thin the plants out to 10 to 12 inches apart.


Dr. Leonard Perry, Extension professor of the University of Vermont, suggests using 20-20-20 fertilizer (20 percent nitrogen, 20 percent phosphorus, 20 percent potassium) least twice during the growing season.

Garden Guides