How to Grow Celosias

Fill several peat seedling pots with seed-starting soil and place them in a warm location. Celosias prefer a soil temperature of 60 degrees Fahrenheit or more so place the pots in a room that is at least 70 degrees Fahrenheit.

Slightly moisten the soil in the peat pots with water then sow three or four celosia seeds at a depth of 1/4 inch in each pot. Cover the pots with plastic film and allow them to sit in a warm location for 10 to 15 days until they have germinated. It is best to sow your celosia seeds indoors four to six weeks before the last frost.

Move the peat pots into a location that gets plenty of bright light -- such as a south-facing windowsill -- or place them under a fluorescent light fixture. If you are using fluorescent lighting you may need to move the fixture as the plants grow to maintain a 6-inch space between the plants and the light.

Allow the celosias to grow undisturbed, spritzing them with room-temperature water to keep the soil moist, until the plants in all of the peat pots have grown two sets of leaves.

Pinch off the stems of all but the strongest-looking celosia seedling in each of the pots. To pinch off the weaker plants, simply break the stem between the fingernails of your thumb and forefinger at the soil level.

Harden off your celosia plants by slowly assimilating them into an outdoor environment. Begin by placing the peat pots outside for about four hours once the overnight temperature has reached 55 degrees Fahrenheit. Increase the amount of time you leave your celosias outside by two hours each day until, by the eighth day, they are ready to remain outside overnight.

Plant your celosias in the garden by cutting away the portion of the peat pot above the soil line and bury the peat pot in the soil to the depth of the pot. Review the planting directions on the seed packet to determine how far apart to space your particular variety of celosia. Smaller celosias should be spaced about 10 inches apart while larger varieties may need 16 inches or more.

Plant juvenile celosias purchased from a garden center or nursery directly in the ground, following the spacing instructions on the plant tag. When planting your celosias, dig a hole only deep enough that the soil level at the top of the hole is the same as the soil level in the cell pack your flowers came in. Water the flowers well after planting.

Grow celosias in a container, if you prefer this method. Select a large pot or container and fill it with several of the smaller varieties of celosia such as the Coral Garden and Castle Pink varieties. Follow the spacing instructions on the plant tag and keep the soil in the container uniformly moist.

Grow celosias indoors by sowing seeds thickly in a large pot. Rather than sowing three or four seeds, sow 12 to 16 seeds to a depth of 1/4 inch in a round pot and thin out the weaker seedlings after they've grown their second set of leaves. Allow eight to 12 seedlings to grow to maturity and keep the soil uniformly moist.