HOW TO GROW FROM SEED
Celosias are warm weather plants and take about 90 days to flower after planting. Like beans, they are not happy unless the soil temperature is at least 60 degrees Fahrenheit. In cold winter areas, get a jump-start on the season by starting the seeds indoors four to six weeks before the last frost date. Celosias do not like to have their roots disturbed, so sow three or four seeds 1/4-inch deep in lightly moistened, sterile seed-starting mix in earth-friendly peat pots. Cover the pots with plastic wrap and put in a warm (70 to 80 degrees Fahrenheit) place until the seeds germinate – 10 to 15 days. Remove the plastic daily to let the plants breathe. Spritz with room temperature (not ice-cold out of the faucet) water to keep the potting mix uniformly lightly moist.
Once the seeds have germinated, move the plants into the light. A sunny south facing window will do, but fluorescent lights are best. As the plants grow, move the lights so they remain about six inches above the tops of the plants. When the plants have two sets of true leaves (not the initial seed or cotyledon leaves), pinch out all but the strongest looking plant.
When the nighttime temperatures are above 55 degrees Fahrenheit, start hardening off the plants. Gradually introduce them to the outdoors, leaving them outside – in a protected area – for part of each day. Start out with four hours and increase the time outdoors by two hours each day. By the eighth day, they should be able to remain out overnight.
Unless you plan to grow celosias in a cutting garden, avoid planting them in soldierly rows. Tear or cut off any part of the peat pot that is above the level of the potting mix. Plant the pot so the peat pot is completely covered with garden soil. Follow the directions on the seed packet for spacing the plants, ten inches apart for small varieties – 16 inches for taller ones – is ample space for air circulation around the plants. Planted too closely, the plants may be stunted, with poor growth and smaller flowers. Water well.
In areas with longer summers, sow the seeds directly in the garden after all danger of frost has passed. Follow the directions on the seed packet for spacing. For best germination, wait until the soil temperature is at least 60 degrees Fahrenheit. Sow the seeds 1/2-inch deep and cover loosely with soil. Keep the soil lightly moist until the seeds germinate. Covering loosely with Reemay� or other spun polyfiber fabric can help maintain soil moisture. Remove fabric immediately after germination. Once the plants have two sets of true leaves, thin the seedlings to the recommended spacing on the seed packet, leaving the largest and strongest plants.