Xerces Society, the foremost organization for promoting pollinator conservation, has these recommendations for sizing a pollinator garden with the goal of providing efficient foraging for the greatest diversity of pollinators:
Plant at least 8 plants each of 9 carefully selected native perennial species with 3 flowering early, 3 flowering mid-season and 3 flowering late, offering a variety of flower shapes, sizes and color with purple, white and yellow being most attractive to bees, our most important pollinators, plus 4 plants of 1 native grass species. If you figure 4 s.f. per plant that is 76 plants x 4 s.f. = 304 s.f..
Of course every little bit can help, even a window box or hanging basket! Don't be dismayed if you don't have room or budget for that many plants. Planting for pollinators does not have to be an independent effort - you don't have to save them all by yourself!
If you do have room and budget, our 84 plant Pollinator Garden collections option most closely meets these guidelines. The collections are offered in multiples of 21, the number of plants in our trays. The 84 plant option provides 8 plants of 10 carefully selected flowering native species plus 4 plants of 1 native grass species, offering constant and overlapping flowering throughout the pollinator foraging season with thoughtful attention to flower color, shape and size. For our 84 plant pollinator garden collection, you should allow 84 x 4 s.f. = 336 s.f..