What is plant population?
Plant population is the number of plants growing on a given area, usually quoted per acre or per hectare. Growers use it to compare yields, order seed and decide how far apart to set the rows.
Planning the rest of the job? Use the Seed calculator and the Plant spacing calculator too.
How does the calculation work?
Plants = area ÷ (row spacing × in-row spacing)
Sweet corn in 30 in rows with 8 in between plants: one plant takes 2.5 ft × 0.67 ft = 1.67 ft². An acre (43,560 ft²) holds about 26,100 plants.
Not every seed comes up. If you expect 90% to survive, divide the plant count by 0.9 to get the number of seeds to sow.
What are typical spacings?
Sweet corn
30 in rows, 8 in apart (75 × 20 cm)
Potatoes
36 in rows, 12 in apart (75 × 30 cm)
Tomatoes
48 in rows, 24 in apart (120 × 60 cm)
Lettuce
18 in rows, 10 in apart (45 × 25 cm)
Bush beans
18 in rows, 4 in apart (45 × 10 cm)