This depends on what type of bulbs you plan on planting. For daffodils, we recommend planting the bulbs 5-6 inches apart, or plant 4 bulbs per sq ft. For smaller spring blooming bulbs such as, galanthus & spanish blue bells, etc. we recommend planting those bulbs 3 inches and 4 inches apart.
Being a gardener, this is what I would do... make groups of 9 so you have 11 groups plus 1. Plant the 9 in a close circle. I find clusters look more impactful and always plant in odd numbers.
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