Buying seeds by guess usually ends with too many packets or a half-empty bed. Enter your bed size and pick a crop, and this calculator works out how many rows fit, how many plants you’ll get, and how many seeds to buy — with a margin for germination and thinning. Pair it with our seed-starting calendar to time your sowing right.
Enter your bed size and pick a crop. Get the number of rows, plants per row, total plants, and how many seeds to buy (with a margin for germination and thinning).
How it’s figured
Rows = bed width ÷ row spacing; plants per row = bed length ÷ in-row spacing (both rounded down). Seeds to buy = plants × 1.5, covering imperfect germination and thinning. Spacing follows standard row-planting guidelines — wide rows suit mechanical cultivation, so home gardeners can often plant a little tighter.