Why do some varieties of vegetables cost so much more?

Factual Questions
1

I can get a 10-lb sack of potatoes for $5
Other potatoes are $3/lb.
Same deal with onions yellow can be 10 times less than white.
Green peppers are 1/6 the price of red and 1/8 the price of orange.

Where is the “market” here? Since these things are not “apples and oranges” but the same basic plant, shouldn’t they be nearly the same trouble to grow? So if people pay more for white onions or red potatoes, why not just grow those?

I assume most end up sold or the store wouldn’t stock them. Seems to me if the demand has that much variance then why hasn’t the supply caught up to the point of parity?

I’m guessing it would take about 2 years for the shift and then all potatoes would be about the same price.

2

Here’s an earlier thread about bell peppers:

http://boards.straightdope.com/sdmb/showthread.php?threadid=109634

3

Supply and demand determines the price.

4

Not really. Some varieties/cultivars of the same basic plant are notoriously poor yielders, but have a far better flavor, or have low resistance to certain diseases/pests/conditions. Some varieties are far more prone to bruising and ripening after being picked to be really cheap. Tomatoes grown for supermarkets generally are bred for keeping their shape and not going rotten too quickly. Flavor takes a back seat to appearance. This is one of the reasons why I rarely eat supermarket tomatoes. I prefer to try to barter with a neighborhood gardener for her excess. I’d grow them myself, but I cannot grow plants. Well, I can’t grow plants unless you count those green fuzzy things in my fridge as plants…

5

Another thing is what you are buying is not just potatoes. You are buying margin services. Handling costs are partly down to weight, partly down to number of items sold, partly down to popularity, partly how spoiled they can get and how fast.

So if you are buying an easily-spoiled unpopular type of potato the wholesale costs (of organising the distribution and quality control system) the retail costs (ordering, stocking, turnover and checking the thing out of the store) are going to be higher per potato.

Plus a 10kg bag of potatoes is less convenient to carry about, whereas I can keep shopping carrying a couple of kilos of sebagoes.