Ask Professor Produce

Why do organic lemons sometimes look more like limes? Commercial lemons are always bright yellow. (Gerry, Minneapolis)

Are green oranges ripe? (Hy, St. Paul)

Color is rarely a reliable indicator of ripeness for citrus fruit, since a number of factors might be at work in a slightly green lemon or orange, none of them traceable to its relative maturity. Excessive nitrogen content in the soil can increase chlorophyll in the fruit, and high ascorbic acid can retard ethylene, which helps all fruit attain its hue. But the most common cause of citrus failing to reach stereotypical color is its blossom's location on the tree. A citrus tree require a great deal of direct sunlight throughout its season, and its fruit needs that direct light for "proper&quot color. Pomologist Edward Heinicke conducted a series of experiments on fruit while still on the tree and in 1966 concluded that "in orchard conditions, fruit grown in the shaded portions of the tree have poorer color and are smaller than those born on the periphery."

But "poorer" is an unfortunate word choice, in the Professor's humble opinion, since color is merely cosmetic when it comes to citrus quality. Heinicke's commercial fruit-industry mentality precludes the idea that consumers might be more interested in the taste of the fruit itself than how bright and shiny its skin is. Heinicke's industry mentality, of course, leads to bizarre behavior, such as injecting green citrus with chemicals (tri- and dichlorophenoxyacetic acid) to both hasten the fruit's harvest and decrease the chlorophyll (the color green) in the rind.

The Professor prefers the mentality of the organic grower. In Growing Fruits and Vegetables Organically, produce gurus Nick and Bradley assert that "some gardeners never bother to guess [citrus] ripeness by color; they just wait until the perfectly ripe fruit falls to the ground." We in Minnesota don't have that luxury, but we can get good organic citrus that has not been chemically treated for the sake of "proper" color.

But don't just take my word for it. See for yourself. Have a Wedge produce worker cut a green orange/lemon for you and you'll see that the fruit under that green skin is ripe and ready to eat or juice.

Everyone says the apple crop is going to be very limited this year. What happened?? I want my cider and Haralsons!! (Yolanda, St. Louis Park)

Professor Produce feels your pain. By the time you read this Yolanda, the apple season will be on wane, but here is my take on what happened anyway.

Apple pollination depends on bees, you see, and bees depend on fairly decent weather to pollinate. A bee can find a good source of nectar and pollen (in, say, a big Haralson orchard) and tell the hive about it with incredible accuracy. They do that little dance that conveys the nectar source by using the sun as a reference point. Even cloudy days and tricky scientists can't deter those willful bees from their appointed pollination rounds, but if wind is routinely over 10 mph, and the temperature drops below 55 degrees Fahrenheit, pollination by bees simply won't happen. So apart from the fact that the brutal winter devastated the midwest's bee population, this past spring proved too cold and windy for those that survived.

Furthermore, "fruit set," when the last of the apple blossom falls away and the fruit begins to grow, requires a great deal of water. This summer, which brought droughts to the southwest, was drier than normal for the midwest. As a result, the reduced number of pollinated apple trees produced undersized apples and a great deal fewer than in years past.

So pray for a warm spring and a wetter summer, Yolanda, if you want your Haralsons to last til Thanksgiving next year.

Are cranberries ever grown organically? (Patty, Powderhorn Park)

The Wedge did not carry organic cranberries last year, and the conventional wisdom in the produce aisle was that cranberries, which grow in a bog, could not realistically be certified. After all, how can a certifier be certain of the water's quality leaching into the bog from the water table below and from surrounding sources? Word is out now, however, that organic cranberries might be on the way, so the Professor did a little research on the matter. There are varieties of "highbush" cranberries, called Phillips and Wentworths, that grow, not in bogs, but on 6' -10' bushes. These berries are very hardy and can remain ripe and ready on the bush throughout the winter. Just a guess, but any organic cranberries you buy will probably be one of these highbush varieties.