Garlic/Marigold Strategy is a very nice strategy that inolves the use of, well, Marigolds and Garlics.
With the awesome power of the Garlics, essentially any row that Garlics are in is free for planting. When we make use of that space by planting Marigolds, we can get massive amounts of Gold. Do that with 3 lanes, you get double the cash. Just be sure to plant it in alternate lanes.
However, one Garlic will not be enough. Pole Vaulters can get over to your defenceless rows, and your Money-makers. Thus, it is wise to Pumpkin the first Marigold and put an attacker in that row, or plant Double garlics.