All together, it costs $, to get all 10 seed slots. One extra seed slot can be obtained in Pirate Seas, in a gate between Day 9 and Day 10 before the update or by completing Day 21 after the update. All you need to do is collect the coins and replace the Garlic after each wave. Note: This strategy will not. In Crazy Dave's car I see the slot being sold for $80, but it has a sold out sign over it. As per the Plants vs zombies wiki: Extra Seed Slot ten - $80, (unavailable on iOS, Mobiles with Samsung bada OS, DS, and Android because. When will I be able to purchase this? Just buy them. It's straightforward, but make sure you've got enough. seed slots plants vs zombies. The. . You must first buy the seventh ($), eighth ($), and ninth ($20,) seed slots. Example This strategy only needs 7 seed slots. You need to purchase each slot one by one until the 10th becomes available.