Survival: Roof (Hard) - Melons and Cobs

This strategy uses Winter Melons and Cob Cannons.

1st round (flags 1-2)
Start planting Sunflowers and use Potato Mine for the first zombie. Everytime a zombie comes, plant a Kernel-pult in the 3rd column in that lane and later Melon-pults in the 4th column. Upgrade some melons to Winter Melons and some Sunflowers to Twin Sunflowers.

S - Sunflower

T - Twin Sunflower

K - Kernel-pult

M - Melon-pult

W - Winter Melon

U - Umbrella Leaf

- Pumpkin

2nd round (flags 3-4)
Have 2-3 Cob Cannons and Umbrella Leaf at the back for Bungees and Catapults. Have melons in columns 4, 5, 6 and upgrade one in each lane to Winter Melon. Use those cobs in huge waves.

C-C - Cob Cannon

3rd round (flags 5-6)
Finish having 5 Cob Cannons. Use them during huge waves and against Zombonies and Gargantuars.

4th-5th round (flags 7-10)
Use the cobs during huge waves and against Zombonies and Gargantuars since there are no Spikerocks to stop them. Replace Umbrella Leaves at the back with melons if there are no catapults.