Passion for pumpkins
Some people passionately collect stamps, while others throw themselves enthusiastically into growing pumpkins. The same goes for the two British brothers, Ian and Stuart Paton. They grew a pumpkin weighing 660 kilos, breaking the European record in the process. The pumpkin variety used in competitions is the Atlantic Giant. And this pumpkin is indeed gigantic. For comparison, 660 kilos of pumpkin is approximately 4300 apples.
The fanatical brothers cultivated the pumpkin in a greenhouse. For this giant, they used 1,5 tons of fertilizer. The pumpkin sometimes grew as much as 22,5 kilos per day and weighed 660 kilos after 129 days. Next year, Ian and Stuart will attempt the world record of 766 kilos. The pumpkin belongs to the same family as the cucumber and the melon. Pumpkins were already being cultivated 7000 years before Christ. There are many varieties. A number of them are used in dishes such as pumpkin bread and pumpkin pie. The seeds can be eaten roasted. Now you might think, “such a special fruit must surely be found on many stamps.”
Nothing could be further from the truth. Not counting the Halloween stamps, I found exactly 2. Could there be more? Which passionate collector will take on the challenge? 
For the pumpkins, you can search for Halloween stamps. Belgium, Austria 2005, there are surely many more.
Oh sorry, I see it says you didn't count the Halloween stamps.
Booklet VS 2006, only they aren't the giant orange pumpkins, but the smaller ones.
Jacqueline:
As far as I can tell, the 4559/62 series from Bulgaria from 2002 is a series of watermelons and pumpkins.
And in 1997 I found the following reference to North Korea:
Vegetables FDC S/S Food Pumpkins Insects. I lack further details. Maybe this is of use to you.
Dolores and Willem, how nice that you have started searching. Being enthusiastic about stamps is one thing, but actually finding the right ones is harder than I thought. Where did you spot the stamps? I could really use some help and tips.
Haha Jacqueline, it wasn't easy this time, you know. Usually I type keywords into the search bar: like this time, pumpins (on)(post)stamps, or pumpkins philately stamps, or ebay after it, or vegetables (on)(post) stamps. Or the Dutch keywords. Thematische Verzamelgids has many links. Freestampcatalogue has a huge number of stamps from all over the world. Last week I discovered that there are also some stamps on wikimedia.commons, and a search engine. Sometimes I know about them from previous searches or because I have the stamp in my collection. The more often you do it, the better you get at it. Just watch out for too many small Arab states, and also Russian ones and exotic islands; some people do collect them—I've had them from the beginning too—but for others they are just stickers because they will probably never see a letter. By the way, I couldn't find the stamps you showed anywhere!
Oh, see, I did overlook one. The beautiful stamp of Sweden on Filahome:
http://www.filahome.com/postzegels/0308oogsttijd.htm
Harvest + art + stamps + philately also yields nice things.
Hahaha, this is me for the last time, this one of course:
http://www.posten.se/img/cmt/FriStorlek/kund_bulletin4_08_eng.pdf
Dolores, thanks for the tips! Very useful for my next searches. And so my arsenal of search options continues to expand.