It's quite expensive - $80, However, you will probably want it if you replay the. . I've bought a lot of plants with REAL money. At the beginning of the game, the player has six slots and can buy more from Crazy Dave's Twiddydinkies. It's where you get to be Zomboss and pick which zombies you would use to defeat a given lawn. But one thing I refuse to do is buy more seed slots. Reply. For Plants vs. 10 seed slots is the max on the PC version, at least. They are unlocked in order; the next one is. Message 9 of 11 (1, Views). The player can purchase more seed slots, plant upgrades, new defenses for the Pool and the Roof, Zen Garden items, upgrades, various House Blueprints (Xbox Live. It alters the game dramatically and I. Zombies on the DS, a GameFAQs Q&A question titled "How can I get 10 seed slots in the ds version?".