10 seed slots is the max on the PC version, at least. 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. Reply. Message 9 of 11 (1, Views). They are unlocked in order; the next one is. But one thing I refuse to do is buy more seed slots. Zombies on the DS, a GameFAQs Q&A question titled "How can I get 10 seed slots in the ds version?". 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. It's quite expensive - $80, However, you will probably want it if you replay the. . For Plants vs.