Planting Density by Crop in cm

Planting density by crop: how to convert row × plant spacing into plants per hectare

To find how many plants fit in a hectare, you take both your spacings into account: plants/ha = 10,000 m² ÷ (row spacing in metres × in-row spacing in metres). Every crop sits in a different agronomic window. Maize usually runs 70 cm between rows and 20 cm between plants, which lands around 71,000 plants/ha. Soybean packs in tighter, closer to 50 × 5 cm. Staked tomato goes wider at 50 × 80 cm, while head lettuce sits at 25 × 25 cm. Run the maize numbers and 70 cm × 20 cm becomes 0.70 × 0.20 = 0.14 m² per plant, so 10,000 ÷ 0.14 works out to roughly 71,400 plants/ha. What you actually settle on depends on the soil, how much water you have, and the architecture (porte) of the cultivar.

Applications

Planning a precision-agriculture operation, calibrating seeders and planters (plantadeiras pneumáticas), setting up GPS guidance and variable-rate seeding, budgeting a seed purchase, working out fertilizer dose per linear metre, and checking your numbers against EMBRAPA and university trials.

FAQ

Why does soybean tolerate such tight spacing? The plant makes up for crowding by branching out, so tight rows close the canopy faster, choke out weeds and stretch the available water further.

When should I reduce density? Sandy soils, low rainfall and short-cycle cultivars usually call for fewer plants, both to dodge water stress and to keep the crop from lodging.

How do I calibrate a pneumatic planter? Take your target plants/ha and use the row spacing to turn it into seeds per linear metre. Then verify the spread with the trapezoid or static method before you head into the field.

Does narrow row spacing always increase yield? Not really. Past a certain point the plants start fighting over light and nutrients, and yield flattens out or even falls back, particularly in dryland fields.