I think buying a few spring onion seedlings may be worth my while too. I love spring onions, love.
This gardener suggests wheat grass in her mix. Wheat grass on it's own, in a salad may well be tasty. I know that I used to eat the sprouts as a child and in some strange hippy food my parents made (was not diagnosed as Coeliac then) and they were sweet.
As someone who had a family member acutely obsessed with wheat grass, who smelt the resulting gourmet product, I am yet to get so sick that wheat grass juice is even remotely tempting. I always go to hospital first. Then again, I'm a coeliac so it's not recommended anyway.
Mercola's horticultural experts have some good tips too. Alas, another recommending wheat grass among other things(oh the smell of the juice, it's enough to make one rail about alternative therapies [blech]).
There's this, and the reminder in the comments to remember that sprouts can grow within days, are high in nutrients and frugal.
In summary, for quick growing greens, consider:
- transplanting seedlings for faster growth outside
- pots and container gardening for people without much land, or who are transient/ renting