Row Orientation & Capture the Most Light
Compares N–S vs E–W
Should your rows run North–South or East–West, and at what spacing, to capture the most light at your latitude? Enter latitude, season and canopy geometry to compare N–S vs E–W daily interception, the gain, the inter-row shading loss and the recommended spacing.
Set up your field
Runs entirely in your browser — nothing is uploaded. Solar geometry per Campbell & Norman; row-shading per Squire (1990).
Next: orient your rows North–South to gain about 24.9 percentage points of daily light (66.6% more than the other way). For a 1.6 m canopy, narrow the spacing toward 1.6 m to cut the 37.7% inter-row loss.
Geometric daily-integration model (Campbell & Norman solar geometry; row-shading per Squire 1990 and Loomis & Connor 1992). N–S is favoured at low latitudes / high sun; E–W at high latitudes and winter. Real interception also depends on diffuse light, leaf angle and canopy development — treat as a planning estimate.
Row orientation — key facts
- Cover fraction
- canopy width ÷ row spacing
- Interception floor
- always ≥ cover fraction
- Solar noon elevation
- 90° − |latitude − declination|
- Low latitude / high sun
- N–S rows usually win
- High latitude / winter
- E–W rows usually win
- Closed canopy
- orientation barely matters
- Recommended spacing
- ≈ canopy height (light wall)
- Equinox day length
- ≈ 12 h at every latitude
- Hemisphere
- symmetric — use |latitude|
- Privacy
- Runs in your browser; nothing uploaded
Canopy presets used by the model
Each preset sets a canopy band width, height and typical row spacing. Tall, wide-spaced canopies (vineyards, orchards) show the largest orientation effect; dense, narrow-row canopies converge. Geometry norms from Loomis & Connor (1992) and extension row-spacing guides.
| Crop / canopy | Canopy width (m) | Canopy height (m) | Row spacing (m) | Cover | Note |
|---|---|---|---|---|---|
| Maize, 75 cm rows | 0.45 | 2.2 | 0.75 | 60% | Tall, narrow band — orientation matters most. |
| Maize, 50 cm rows | 0.40 | 2.2 | 0.50 | 80% | Narrow rows close the canopy fast. |
| Soybean, 75 cm rows | 0.35 | 0.9 | 0.75 | 47% | Open early; slow to close. |
| Soybean, 38 cm rows | 0.32 | 0.9 | 0.38 | 84% | Narrow rows lift early interception. |
| Cotton, 1 m rows | 0.55 | 1.2 | 1.00 | 55% | Wide rows leave big light gaps. |
| Potato, 90 cm ridges | 0.60 | 0.6 | 0.90 | 67% | Ridged rows; mid canopy. |
| Grapevine VSP, 2.4 m rows | 0.50 | 1.6 | 2.40 | 21% | Tall, very narrow wall — strong orientation effect. |
| Orchard hedge, 4 m rows | 1.80 | 2.8 | 4.00 | 45% | Tree wall; inter-row shading is large. |
| Vegetable bed, 1.5 m beds | 0.90 | 0.5 | 1.50 | 60% | Wide beds, low canopy. |
Seasons modelled: Spring (equinox), Summer (solstice), Autumn (equinox), Winter (solstice) (declinations from the Cooper 1969 approximation).
Why row direction is a latitude decision, not a rule
Light is the raw material of yield, and a row crop only captures the light that lands on its canopy rather than the bare strip between rows. How much of the day's light the canopy catches depends on the cover fraction — the share of ground the canopy band covers — and on how the strip casts shadow across the gaps as the sun moves. The cover fraction sets a floor the canopy always meets; the moving sun lifts interception above it, and how much it lifts depends on whether the rows run with or across the sun's daily arc.
Near the equator the sun rides high and sweeps a broad east-to-west path, so North–South rows — whose inter-row gaps run east–west — are shaded efficiently through the morning and evening, intercepting more light over the day. At high latitudes the sun stays low in the south, and an East–West wall that turns its broad south face to that low sun captures more. Between the two, and once a canopy closes, the difference shrinks toward nothing. That is why "always plant North–South" is a myth: the right answer flips with latitude, season and canopy size, which is exactly what this calculator resolves.
This tool reports the daily light intercepted for N–S and E–W rows, the percentage-point gain, the inter-row shading loss and a recommended spacing from your latitude, season and canopy geometry. Use it to set row direction and spacing at planting. Pair it with the Cereal Lodging Risk Index, Photothermal Quotient Yield Potential and Chill Portions Dynamic Model tools for a full crop-planning workup.
How to use it — five steps
- 1
Enter your latitude
Type your latitude in degrees; use its absolute value for either hemisphere (0–66°).
- 2
Pick the season
Choose spring, summer, autumn or winter so the model uses the right solar declination and day length.
- 3
Describe the canopy
Select a crop preset or set the canopy band width, height and row spacing directly.
- 4
Read the comparison
See the daily light intercepted for N–S vs E–W rows, the verdict and the percentage-point gain.
- 5
Tune the spacing
Use the recommended spacing and the inter-row loss figure to narrow rows where light is being wasted.
Frequently Asked Questions
Should my crop rows run North–South or East–West?+
It depends on your latitude and season. At low latitudes and in high-sun seasons, North–South rows usually intercept slightly more daily light, because the high sun arcs across the sky and its low morning and evening east–west angle sweeps shadow across the inter-row strips. At high latitudes and in winter, East–West rows often win, because a persistently low southern sun strikes the south face of an east–west canopy wall all day. Enter your latitude, season and canopy geometry to see the exact comparison and the percentage-point gain.
How is daily light interception calculated?+
The tool integrates the sun's real path across the day. For your latitude and the season's solar declination it computes the sunrise-to-sunset hour angles, then the sun's elevation and azimuth each step (Campbell & Norman solar geometry). At each step the canopy intercepts the beam over its own footprint plus the shadow the strip casts across the inter-row, capped at full cover, weighted by beam irradiance. Summed over the day this gives the fraction of daily light intercepted for North–South and for East–West rows.
How much difference does row orientation actually make?+
Usually a few percentage points of intercepted light, sometimes more for tall, wide-spaced canopies like vineyards and orchards where the inter-row gaps are large. For a closed canopy with narrow rows the two orientations converge, because the ground is fully covered either way. The tool reports the percentage-point gain of the better orientation so you can judge whether it is worth committing to.
Why does latitude change the best orientation?+
Latitude sets how high the sun rides. Near the equator the sun passes almost overhead and tracks a wide east-to-west arc, so North–South rows — whose gaps run east–west — are swept by shadow through the morning and evening. At high latitudes the sun stays low in the south, so an East–West wall presenting its broad south face captures more. That is why no single rule fits every field; orientation is a latitude × season decision.
What row spacing should I use?+
A useful rule of thumb is to set spacing close to the canopy height so the rows form a balanced light wall that closes without excessive mutual shading. Tall crops therefore benefit from narrower rows. The tool reports a recommended spacing equal to the canopy height and shows the inter-row light loss at your current spacing, so you can see how much light a tighter spacing would recover.
What is the cover fraction?+
Cover fraction is the share of the ground the canopy band covers, calculated as canopy width divided by row spacing, capped at one. A 0.5 m canopy band in 2.4 m rows covers about 21% of the ground. Daily interception can never fall below the cover fraction — the canopy always intercepts at least its own footprint — and rises above it as the moving sun casts shadow across the gaps.
Does this work in the Southern Hemisphere?+
Yes. The geometry is symmetric about the equator, so enter your latitude as a positive number (its absolute value). In the Southern Hemisphere the low-sun wall faces north rather than south, but the orientation that wins — North–South versus East–West — is the same as the mirror-image northern latitude. The season labels follow the sun, so pick the season by whether the sun is high (summer) or low (winter) where you are.
Is North–South always better?+
No — that is a common myth. North–South rows win at low latitudes and high-sun seasons, but East–West rows can intercept more at high latitudes and in winter when the sun stays low in the south. The advantage also shrinks to nothing once a canopy closes. This calculator exists precisely because the answer flips with latitude, season and canopy geometry.
Does row orientation affect yield?+
Light interception drives biomass and, through it, yield potential, so an orientation that captures a few percent more light over the season can lift yield where light is limiting. The effect is largest for wide-spaced, tall canopies and smallest for dense, fully-closed canopies. Orientation is one lever among many — spacing, plant population and canopy management usually matter more — but it is essentially free to choose at planting.
How does season change the result?+
Season sets the solar declination, which moves the sun higher (summer) or lower (winter) and changes day length. A higher summer sun favours North–South rows; a low winter sun favours East–West. Day length also changes the total light available. Switch the season in the tool to see how the orientation advantage shifts across the year for your latitude.
What does inter-row shading loss mean?+
It is the share of daily light that falls on the bare ground between rows rather than on the canopy — light the crop does not capture. The tool reports it as one minus the best orientation's interception. High inter-row loss signals that the rows are too widely spaced for the canopy size, and that narrowing the spacing or speeding canopy closure would recover yield-driving light.
Is the calculator a substitute for a full radiation model?+
It is a sound planning model for the beam (direct) component using real solar geometry, but it simplifies diffuse light, leaf angle distribution and day-to-day canopy growth. Use it to decide orientation and spacing at planting and to compare scenarios, then validate with on-farm light measurements or a detailed canopy model where the margin is tight.