Best case is 8 seeds, you can plant before the glazenuts/sun lemon/apricots are done. So when you harvest the apricots and get seeds, you then plant the sun lemon before the glazenuts are ready. Then pick the glazenuts and plant them while the sun lemon is growing, then pick the sun lemons and plant apricots and so on.
You don't wait for everything in the garden to finish, you just keep planting as soon as you harvest one. This makes 8 seeds possible from the garden each step.
Also, if you get short on glazenut seeds than just plant 4 glazenuts, 3 sun lemon and an apricot one go around to get that extra glazenut seed since your apricot stash keeps going up.
A good Gardener can plant that 1 seed different that will get them what they need as well as plant in the correct order to ensure the crosses they need. Remember that it will cross with whatever is next to it when its planted, then you can put something else next to it and they won't cross. So you can totally control what you get.
