How we decide what's in season

Three states

The whole table

Every checked food, with the months it is in its Dutch season, its best months, and the months Dutch produce of it comes from store or from unheated glass. Any month not named is outside the Dutch season.

Open the interactive season guide →

Where the windows come from

Vegetables and fruit follow two published calendars from the same growing climate as the Netherlands, both of which separate the harvest season from the extended one: the Belgian consumer organisation's calendar with the Flemish agriculture department, and the Brussels environment agency's calendar, which marks storage months. Where a Dutch tradition or rule fixes a window, such as asparagus ending on 24 June or the first herring in June, the Dutch source wins and is cited. Game follows the legal hunting seasons published by the Dutch hunters' association. Mussels, oysters and honey follow the trade and beekeepers' own statements. Harvest-share windows and package rounds come from the producers' own pages.

Where sources disagree by a few weeks, the narrower Dutch open-field window is used and the note on the food's page says so. The sources are listed on every food page with the date they were read.

• Groenten- en fruitkalender (Belgische productie), Test-Aankoop with the Vlaams Departement Landbouw & Visserij, 2026: Separates the original season (open air or cold glass) from the extended season (heated glass or intensive cold storage). Belgium shares the Dutch growing climate; we read it for the growing months.
• Seizoensgroenten en fruit, Leefmilieu Brussel / Good Food, 2025 edition: Marks harvest months and storage months separately, per season.
• Seizoenskalender: seizoensgroenten en fruit, Jaimy's Kitchen: A Dutch month-by-month list of Dutch-grown produce.
• Aspergeseizoen begint met vliegende start, Akkerwijzer: The Dutch asparagus season traditionally opens on the second Thursday of April and ends on Sint-Jan, 24 June.
• Dit is waarom de asperges na 24 juni niet meer gestoken mogen worden, Omroep Brabant: The start moves with the weather; the end is fixed at 24 June so the plants can recover.
• Jachtseizoen, Koninklijke Nederlandse Jagersvereniging: Legal hunting seasons per species in the Netherlands; deer and wild boar are managed per province.
• Wanneer zijn mosselen op hun lekkerst?, MAX Vandaag: Dutch mussels are sold from July (on average from mid-July) until about April, and are at their best from September to November.
• Kom oesters proeven in Yerseke, DagjeWeg: Oysters are gathered in the months with an r; in summer the water warms and the oyster turns milky.
• Eerste Hollandse Nieuwe aangeboden, NOS, 11 June 2020: The first barrel of Hollandse Nieuwe comes ashore in the second week of June; the season opens on Vlaggetjesdag in Scheveningen.
• Voorjaarshoning, Beeffet (beekeeper): Spring honey is harvested in April and May; summer honey comes from June to August.
• Een heel seizoen stap-voor-stap, Imker Herman (beekeeper's log): Heather honey is harvested at the end of September.
• Graskaas, Wikipedia: Graskaas is made from the first milkings after the cows go out to grass in spring and is sold in early summer.
• The producers' own pages, as recorded in The Field Guide's notes: Harvest-share and pick-your-own windows as the producers state them on their own websites.
• NEVO-online, the Dutch food composition database (RIVM): Nutrient content per food. The nutrient notes on the food pages name what a food is notable for according to NEVO and comparable composition tables; they describe content, not effects.
• Regels rondom het plukken van paddenstoelen, Vroege Vogels (BNNVARA): Staatsbosbeheer tolerates small amounts for your own use, about a 250-gram punnet, from the paths; nature reserves such as Zuid-Kennemerland and Natuurmonumenten areas forbid picking; commercial picking is forbidden everywhere.
• Zeeuwse traditie om zeegroenten te snijden verdwijnt langzaam maar zeker, NOS: Wild samphire and sea aster in Zeeland may only be cut under licence, and from 2026 only after the breeding season, 15 July to the end of August.

How producers are matched

The Field Guide records what each producer sells per product group and, for animals and fish, per species. So lamb, beef, mussels, oysters, herring, raw milk, farm cheese, honey, eggs and game are matched to the producers who sell them. For vegetables and fruit we read each grower's own website and shop lists and recorded the crops they name, with the sentence it came from, so the pumpkin page lists the growers who say they have pumpkins. A grower whose site names no crops stays under "growers to ask": they may well have it, we just cannot say so.

Pick-your-own is taken from the producers' own buying channels. "Near you" counts use the same distance rule as the map: the nearest of the farm itself and its pickup points.

What this table is not

It is not an environmental score and not a nutrition claim. It says when a food is Dutch and from the field, nothing more. Weather moves every window by a week or two in either direction; the producers' own announcements beat the table.