Plan · study glasshouse (greenhouse · 13 periods)
Profit-optimal planting calendar, six crops
10,000 m² and 7 FTE, allocated over thirteen 4-week periods. Each scenario below is a data override on the same ledger; the published source solved the same six cases.
Optimal profit
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EUR / year
Published
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source result
Δ vs base plan
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EUR / year
Ground use
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mean of 13 periods
Labor use
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mean of 13 periods
Binding periods
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of 26 resource-periods
Cultivation plan — m² per crop per period
Darker cell = more area. Hover a cell for the exact value.
Ground — % of 10,000 m² used
Gold number = shadow price: extra annual profit per additional m² in that period. A full bar without a number means the ground is used up, but more ground there would not earn more.
Labor — % of 67,200 min used
Same reading: a shadow price marks the periods where extra hours pay; a full bar without one means the hours are spent, but more hours would not earn more.
Scenario comparison
Optimal annual profit per scenario, model vs published. Click a scenario above to inspect its plan.
| Scenario | This model | Published | Match |
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Planning under price uncertainty · Women's Day (harvest period 3)
The Women's-Day spike is certain — how high it goes is not
Tulips, freesia and lilium harvested in period 3 catch the Women's-Day demand spike — and planting is committed months earlier, so the plan cannot wait for the price. Every candidate plan is tested against three futures for that period: the spike comes in strong (three times the usual period price), elevated (×1.8), or fails (×0.9 — export or currency trouble). The tabs below compare how each plan holds up.
How this plan holds up in each future
Annual profit under each price future, and what it averages out to.
Strong spike
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35% likely
Elevated
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40% likely
Spike fails
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25% likely
Average outcome
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weighted by likelihood
If prices disappoint
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average of the worst outcomes
Spike crops in period 3
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m² harvested into the peak
What this plan changes on the ground
Period-3 harvest area per spike crop. Gray bars: the base plan, for comparison.
All plans side by side
The selected plan's row is highlighted. Click a tab above to inspect a plan.
| Plan | Strong spike (35% likely) | Elevated (40%) | Spike fails (25%) | Average outcome | If prices disappoint |
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The percentages are the assumed chances of each future — a strong spike in roughly 1 year in 3, an elevated one in 4 of 10, a failed one in 1 of 4. Average outcome weighs the three profits by those chances. If prices disappoint is the average of the worst quarter of outcomes — the number a cautious planner watches. The period prices themselves are real auction data (2004–2006 averages); the chances are still working assumptions — per-year weekly auction prices would turn them into measured frequencies.
Planning answer
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Source: Kromhout, R.M. (2007), Cultivation planning for flower production: a model in linear programming, TU Delft MSc thesis — model, scenarios, and reference results. Prices: FloraHolland 2004–2006 period averages, as published. Solver: HiGHS (SciPy) on a crop-period ledger; “faster tulips” differs −0.03% from coefficient rounding in the source. Shadow prices reproduce the published tables. Uncertainty block: mean-CVaR extension of the same LP; scenario probabilities are working assumptions, not fitted.