Cauliflower Seed Germination
Cauliflower grows best at around 60 F. (15 C.). Too far below that and the plant will die. Too far above it and the head will “button,” meaning it will break off into lots of small, white parts instead of the desired solid, white head. Avoiding these extremes means growing cauliflower from seeds very early in the spring, then transplanting them outside. The best time for planting cauliflower seeds indoors is 4 to 7 weeks before the last average frost. If you have short springs that get hot quickly, you should aim for closer to seven. Sow your seeds in fertile material at a depth of half an inch (1.5 cm) and water them thoroughly. Cover the soil with plastic wrap until the seeds have sprouted. Cauliflower seed germination usually takes 8 to 10 days. When the seedlings appear, remove the plastic and keep the soil evenly moist. Place grow lights or fluorescent lights directly over the seedlings and set them on a timer for 14 to 16 hours per day. Keep the lights just a few inches (5 to 10 cm.) above the plants to keep them from getting long and leggy.
Growing Cauliflower from Seeds
Transplant your seedlings outside 2 to 4 weeks before the last frost date. They’ll still be sensitive to cold, so make sure to harden them off carefully first. Set them outside, out of the wind, for about one hour, then bring them inside. Repeat this every day, leaving them outside an hour longer each time. If it’s unusually cold out, skip a day. Keep this up for two weeks before planting them in the ground.