Greens and alliums go together like a perfect pair. Greens like lettuce come on for a few weeks, then you harvest the head and they're gone! Plant the shallots (in sets of 3) in between the lettuce. So when the lettuce is done growing, it's the onions turn to take over and grow in that space. They'll take over and you'll have 2 crops for the space of one!
 
This 4-pack include:
1 Green Butterhead
1 Mini Little Gem Lettuce head
2 Shallot sets