Do take care of problems when you first notice them. If you see a leaf turning yellow, a white mildew starting to appear, black spots or you see pests, take care of the problem right away. because the longer you wait, the harder it will be to get it under control.
Growing onions can be done from seed, transplants or sets. When choosing seed to start your onions, you will have a larger choice of what you can plant, but can take five months for the seedlings to mature enough to be transplanted and they are more susceptible to disease.