I have read a lot of books that recommend starting broccoli seeds indoors. Why would I want do this instead of just planting them in the directly in the ground? Broccoli is a cool season crop. You can start it before the final frost free day. Although since the soil is cold, germination will take longer. Broccoli does not like really warm temperatures. If it experiences them for too long a time, then the plant will bolt or go to seed. If you want to grow broccoli in the spring, you are best off starting them indoors, that way you can get a head start, to be sure the harvest comes before the summer.
Here is my plan for growing the seeds indoors:
1. First I plant each seed into a peat pellet. Place them into a container and water the bottom, so the pellets soak up the water, without distributing the seeds.
2. Once the seeds begin to sprout in 7-10 days, I will place them under a grow light. Light from your window probably won't be good enough. And if your light source is too far away, the plants will grow tall and leggy and they probably won't make it. That is why I will try to keep my plants only a couple inches from the glow light.
3. To help strengthen the stems, I will occasionally turn a fan onto the seeds, in order to simulate wind. Keep the fan on low, so you won't damage your seedlings.
4. Once they develop their first true leaves (these are the leaves that come after the first "leaves" show up) then I will transfer the pellets into a large peet container that has seed starting soil in it. Seed starting soil will give your seeds the best chance to grow.
5. I will try to keep my plants as the same distance from the light as they grow.
6. Once it's time to plant my broccoli outdoors, I will need to harden them off. This means taking them outside for 1 hour the first day and increasing it by an hour a day until they are staying out overnight. This way the plant has a chance to adapt to outdoor conditions without going into shock. Once I reach the overnight point, it will be time to plant, my plant into the ground.
Read my earlier post on choosing broccoli varieties.