A Google search produced the following schedule for sowing of seeds for the Veggie Garden. From my experiences over the years, I think some of these dates are a bit earlier, in particular, the warm weather plants, such as tomatoes and peppers.
Now, if I want to grow some tomatoes and peppers in a bucket, I think those dates will work fine. I will probably try a couple of plants to see how things would go, as I grew tomato plants in Florida in buckets with decent success.
Below are images of seedlings I started already, the latest ones being broccoli, cabbage and a cross section of flowers. I am also in the process of transplanting onions into larger cups, first using yogurt cups and now the red plastic Solo cups.
Transplanting the different varieties of onions went well, and they seem to have handled the move nicely. I did not separate the onions, thus there are bunches close together. When eventually planting them outside, it is relatively easy to separate them as the roots are quite resilient.