The player should plant the Peashooters and Wall-nuts as soon as possible. The reason for this is not to make an early setup, but to create a situation where only Tangle Kelp will arrive on the conveyor belt, which will be vital.
As hinted before, Peashooters and Wall-nuts are not very important for this level. A situation where they prove to be worthwhile is when the first Low Tide occurs. There is almost no chance that the player will have killed every zombie with Tangle Kelps by then, so finishing them off with Peashooters is important.
However, the player need not worry too much about this as a high tide will occur relatively soon after that.
Tangle Kelps are the key for this level. They should be planted quickly so that new ones are always coming in on the conveyor belt. Feeding them with Plant Food is not necessary, but it can be done on the final wave. Leftmost zombies that are not basic Pompadour and Bikini Zombies should always be the priority.
The small number next to the zombie icon means that zombie will always appear in that lane, with 1 being the topmost lane and 5 being the bottommost one.