Quick Reference

Type of Harvest: Continuous harvest

Transplant/Direct Sow: Direct sow or transplant in degradable pots. They do not transplant well.

When to Plant: Start seeds indoors 8 weeks before the average last frost date for spring. Zinnia do not like cold weather. Direct sow outdoors when the soil temperature is around 70-80°F.

Days to Germinate: 5-25 days - faster in warm weather, slower in cooler weather.

Days to Maturity: 60-70 days

Planting Depth: 1/4 ” deep

Germination Temp: 60-70°F

Seed Spacing: Plant 2” apart. Thin to 10-12” apart.

Row Spacing: 4" to 24" apart - Crowd them together for support.

Light: Full sun

Soil pH: 5.5-7.5 pH

Water: 1- 1 ½” of water per week

Soil Temperature: Minimum 60°F. These are warm weather loving plants.

Fertilizer: 10-10-10 N-P-K ratio One pound per a 10x10 foot block.

Rotation: Not needed for Zinnia if you amend the soil.


Harvest Type

Zinnia plants are a continuous harvest throughout the summer and into fall. They will die at the first frost.

Transplant / Direct Sow

In the spring, start seeds indoors about six to eight weeks before the average last frost date. Direct sow zinnia seeds in late spring when the soil temperature is warm at 60-70°F. Transplant seedlings when they are 3-4 inches tall, have 4-5 sets of leaves, and when the soil temperature is above 60°F.


Full Sun

When to Plant:

Transplant or direct sow seeds when the soil temperature is 60°F and all danger of frost is past.

Days to germinate

It takes most Zinnia cultivars 5-25 days to sprout. If the weather is warmer and the seed are kept moist, zinnia seeds will germinate quicker.

Days to maturity

It takes about 60-70 days Zinnia to start blooming. Once they begin to bloom they will do so all summer long until the first frost.

Planting Depth

Plant seeds 1/4" deep.

Germination Temperature Range

Germination is best when the soil is 60°F.

Spacing Between Plants

Plant seeds 1-2" apart and thin to 10-12". Zinnias have a short root zone but a wide stance. Place them 12" apart to achieve more prolific blooming.

TIP: Zinnia plants are excellent for attracting pollinators to your garden. They will help improve crop yields if you spread a few zinnia plants around your garden.

Companion Plants

Most vegetables, especially flowering veg such as zucchini. They do well with Cosmos through cosmos do not like as much water as zinnias do. Dahlia and ornamental grasses are also good companion plants.

Growing conditions

Zinnia like nutrient rich soil that is moist. Water to keep the top eight inches of the bed moist but not soggy. Plant zinnias in full sun a balanced fertilizers such as 10-10-10 is good to start with and then again lightly when the blooms start.

Tip: Wind can be a problem for zinnia which are easy to blow over. Plant them along a fence or provide them with a low trellis. You can also twine them into smaller groups to add support.


It is not necessary to rotate zinnia. Start the next year off with fresh compost.

Anticipated yields

Plan your garden yield at 1-2 Zinnia plants per person. A single Zinnia in good healthy will produce 40 or more blooms over the growing season.