Harvest Timing & Harvest Now or Wait to Dry Down?
Weighs drying cost
A days-to-harvest tool gives a calendar date — it doesn't weigh the money. Enter your crop, weather and costs to get the economically optimal harvest day, the cost of harvesting now wet vs waiting for in-field dry-down, the dollars saved and the break-even wait window — where the falling drying-cost curve crosses the rising field-loss curve.
Enter your crop & costs
Dry-down ≈ 0.4 pts/day in average weather
Next: harvest now and dry — every extra day standing adds ear drop, stalk lodging & ear rot faster than the field dries, so waiting only burns money. Get the wet grain off and into the dryer.
Dry-down 0.4 pts/day is a weather-driven planning figure (corn ~0.4–0.8 pts/day warm, far slower late/cool); field loss bundles shatter, lodging, bird and quality discount. Values are from extension harvest-timing / dry-down / field-loss studies — calibrate to your dryer, weather and crop, and let grain quality and the forecast override a marginal call.
Harvest timing & field loss — key facts
- Total cost
- drying $ + field-loss $ (U-shaped)
- Optimal day
- the minimum of the total-cost curve
- Corn dry-down
- ≈ 0.4–0.8 pts/day warm, 0.1–0.3 cool
- Drying cost
- ≈ $0.02–0.05 / point / bushel
- Highest-loss crop
- canola (pod shatter) — short window
- Break-even day
- last day no costlier than harvesting now
- Wait pays when
- drying dear + loss slow + fast dry-down
- Override
- let weather forecast & quality decide close calls
Crop dry-down, loss & moisture presets
Typical standing & target moisture, base field-loss rate, dry-down responsiveness and dominant in-field loss by crop, used by the calculator. The dry-down rate also scales with the weather setting (warm & dry 0.7 pts/day base → cool & damp 0.2). Representative planning values from extension harvest-timing, dry-down and field-loss studies.
| Crop | Standing % | Target % | Floor % | Loss %/day | Dry-down × | Main field loss |
|---|---|---|---|---|---|---|
| Corn (maize) | 25 | 15.5 | 15 | 0.4 | 1 | ear drop, stalk lodging & ear rot |
| Wheat | 18 | 13.5 | 11 | 0.5 | 0.8 | head shatter, sprouting & test-weight loss |
| Soybean | 16 | 13 | 9 | 0.6 | 1.1 | pod shatter & splits |
| Canola | 12 | 8 | 6 | 0.9 | 1.2 | pod shatter (very high) — the classic timing crop |
| Rice (paddy) | 22 | 14 | 13 | 0.5 | 0.7 | shatter, lodging & head-rice (fissuring) loss |
| Grain sorghum | 20 | 13.5 | 12 | 0.6 | 0.9 | bird damage, lodging & head loss |
| Sunflower | 18 | 9.5 | 8 | 0.7 | 1 | head drop, bird & blackbird damage, shatter |
Two costs that cross — the economic harvest day
Leaving a ripe crop standing is a wager. Every day it dries a little in the field, so you pay less at the dryer — but every day it also sheds yield to shatter, lodging, birds and weathering, and may slide down the quality grid. Drying cost falls and field loss rises; plotted over days, the two lines cross and their sum dips to a minimum. That minimum is the day that puts the most money in your pocket, and it is rarely the calendar date a days-to-harvest tool returns.
This calculator turns your crop, weather, moisture, yield, price, drying cost and field-loss rate into the optimal harvest day, the cost of harvesting now versus waiting, the dollars saved and the break-even wait window. Use it to decide whether to run the dryer or let the field do the work, to see how a dry spell versus a wet one shifts the call, and to know how long you can defensibly wait. Pair it with the Cardinal Temperature Emergence and GDD-to-Maturity tools to plan the whole season around the right harvest day.
How to use it — five steps
- 1Select your crop and the drying weather — this sets the in-field dry-down rate.
- 2Enter your standing moisture and the storage-moisture target you must reach.
- 3Enter yield, grain price, drying cost per point and the field-loss rate per day.
- 4Read the optimal harvest day, its moisture and the lowest total cost per acre.
- 5Compare harvesting now with waiting, see the dollars saved and the break-even wait window.
Frequently Asked Questions
Should I harvest now and dry, or wait for the field to dry the crop?+
It depends on two costs that move in opposite directions. Waiting lets the crop dry in the field, cutting your drying bill, but each day standing adds field loss from shatter, lodging, birds and quality discounts. The tool plots both as curves over the days you wait; the total cost is U-shaped, and its lowest point is the economically optimal harvest day. If drying is dear and loss is slow, waiting pays; if loss is fast and the crop barely dries, harvest now.
How does the calculator find the optimal harvest day?+
For each day d it estimates field moisture (start moisture minus the weather-driven dry-down rate, floored at the crop's equilibrium), the points still to dry to your target, and the drying cost (points × $/point/tonne × yield). It adds the field-loss cost (loss %/day × days × yield × grain price). The optimal day is the one with the lowest total of drying plus field loss — where the falling drying curve and rising loss curve combine to a minimum.
How fast does corn dry down in the field?+
In-field corn dry-down runs roughly 0.4–0.8 moisture points per day in warm, dry weather and falls to 0.1–0.3 points per day in cool, damp, late-season conditions. The tool uses a weather setting to scale the rate per crop, so warm-and-dry shows a fast dry-down (waiting more attractive) and cool-and-damp a slow one (waiting buys little drying).
What is the break-even wait window?+
It is the last day on which standing in the field still costs no more than harvesting today. Up to that day, dry-down savings at least offset accumulating field loss; beyond it, waiting is a net loss. So the optimal day is the cheapest day, and the break-even day is the latest you can defensibly wait — useful when weather or logistics force a delay.
Which crop loses the most by waiting to harvest?+
Canola is the classic shatter-prone crop — pods split and drop seed quickly once ripe, so its field-loss rate is high and the window short. Wheat (head shatter, sprouting, test-weight), soybean (pod shatter, splits), sunflower and sorghum (head drop, birds) also lose fast. Corn loses more slowly to ear drop and lodging, which is why corn is more often left to dry down in the field.
How do I estimate my drying cost per point?+
Drying cost is commonly quoted per moisture point per unit of grain — removing one percentage point of moisture from the whole crop. As a rough planning figure it is about $0.02–0.05 per point per bushel, which the tool expresses as dollars per point per tonne. Multiply by the points you must remove (current minus target moisture) and your yield to get the drying bill per acre.
Does weather change the answer?+
Strongly. Warm, dry weather speeds dry-down (more reason to wait) but also tends to reduce per-day field loss, while cool, damp weather slows dry-down and accelerates weathering and lodging. The weather setting scales both the dry-down rate and the field-loss rate, so the optimal day can swing several days between a dry spell and a wet one.
What moisture should I aim to harvest at?+
Aim for the moisture at the optimal day the tool reports — typically a little above your storage target, because the last points are slow and expensive to gain in the field and risky to wait for. Harvesting slightly wet and finishing in the dryer often beats chasing the final points, especially in shatter-prone crops or unsettled weather.
Why is total cost U-shaped?+
Early on, the crop is wet so drying cost is high while field loss is near zero — total cost is dominated by drying. As you wait, drying cost falls but field loss climbs; eventually the rising loss outweighs the falling drying. The sum therefore dips to a minimum and then rises, and that dip is the day with the lowest combined cost.
Are these dry-down and loss rates exact for my field?+
No — they are representative planning values from extension harvest-timing, dry-down and field-loss studies, not a measurement of your field. Dry-down depends on hybrid, weather and canopy; field loss depends on variety, lodging and pest pressure. Use the tool to frame the decision and the dollars, then adjust the rates to your own experience and let the forecast and grain quality override a close call.
What if I can't harvest on the optimal day?+
Use the break-even wait window: any day up to it costs no more than harvesting today, so you have flexibility for weather and machinery. Past the break-even day, factor the rising loss into your scheduling — and remember that a real rain or wind event can wipe out the modelled savings, so when the call is close, take the grain off.