do you need to plant all 9 pods at once or can you start with 3?
Do you mean if it’s ok to plant 3 pods out of a 9pack? That’s fine to do so. Just store the remaining pods in a dry and dark place so that seeds would remain viable. Usually, pods remain viable for a year ot two after purchase, depending on the storage conditions.
Or,
did you mean to ask whether to fill only 3 cups of a smart garden 9 first and leave other cups empty?