Mary, Mary, quite contrary, how does your garden grow? With 6 packs of seeds, 5 pounds of fertilizer, and 8 plants in every row. You may not have noticed, but numners are a part of every well-planned garden. We use numbers to figure out how many seeds to buy, how much space each plant needs, how much money we'll spend, and more. Learn how to grow a garden that looks good enough to eat.