Ask a Gardener: How to grow nutrient-dense fruits and vegetables

Question: I’ve heard that there are nutritional differences in the varieties of fruit or vegetable you buy/grow/eat. Seems silly not to get the best. As a gardener, how do I find the nutritionally best vegetables and fruit plants and seeds?

Answer: You are absolutely correct. There are large differences in the nutritional value of various types of the same vegetable or fruit. Much of it, of course, is due to the way in which those plants are grown. Rich soil contributes to better plant nutrition. Poor soil produces less nutrition in plants. It’s common sense, and the reason why veteran vegetable growers pay so much attention to their soil quality.

However, there is also the issue of the vegetable and fruit varieties themselves. Studies have been done that show that the nutritional quality of the varieties matters a lot. A study published in the Journal of Nutrition in 2013 found that participants age 65 and older who consumed highly nutritious fruit and vegetable varieties for a 12-year period had a 30 percent lower mortality rate compared with those who consumed less nutritious varieties.

So how do these plants work to benefit those who eat them? Through their rich supply of “phytonutrients.” These are compounds that protect the plants from diseases, fungi, insects, harmful ultraviolet light, drought and many other problems. When we eat the plants, we also derive protection from many of the same problems. The plants’ protection becomes our own.

Scientists studying plant nutrition at Cornell University are beginning to believe that the benefits we humans derive from plants are not only due to vitamins, minerals and fibers, but also from the phytonutrients they contain. Much research is being done on phytonutrients, and results so far are astounding. A number of phytonutrients have been shown to reduce the risk of cancer, heart disease, stroke, Alzheimer’s and Parkinson’s diseases. They may also have a positive effect on the immune system and hormones. Research is showing that they act as antibacterial or antiviral agents. And all those beautiful colors adorning fruits and vegetables? phytonutrients are responsible for those.

As we wait for more research and results, it seems smart for those of us who grow our own vegetables and fruits to begin to consider using seeds that will produce highly nutritious plants. Seriously. If you’re growing any plants, doesn’t it make sense to plant the varieties that are the best nutritionally? After all, it’s no more work.

These aren’t necessarily new varieties, either. Some crops that have been grown for many years are much more nutritious than many newer types. A good example is the Liberty apple. It was developed by the New York State Agricultural Experiment Station, and contains two to three times more phytonutrients than most supermarket varieties. It is also highly resistant to apple scab and fire blight, nasty destructive apple diseases.

Yet, as compelling as all this is, it can be overwhelming. So here are a few guidelines to help you increase the nutrition of the foods you grow.

• Know that heirloom plants, that current craze among some gardeners, are not necessarily better. A good example is the commonly planted Thompson Seedless grape that’s become one of the most popular in the United States. But studies have shown that there are several newer varieties that contain many more phytonutrients, varieties that grow as well, and taste as good, but are more nutritious. What’s not to like?

• Bigger is not better when it comes to phytonutrients. Reasons why? Large varieties of fruits and vegetables contain much more water, which dilutes the nutritional content as well as the flavor. And they have less skin per ounce. Many of the phytonutrients are concentrated in the skin of fruits and vegetables.

• Some of the most beneficial phytonutrients have a bitter, spicy, tart or astringent flavor. The American public has shown its preference for milder flavored foods — take iceberg lettuce, for example. Sharper flavored greens, such as radicchio and arugula, have many more phytonutrients. Red lettuce trumps green lettuce nutritionally.

• Choose vibrant fruits and vegetables colored red, orange, yellow and purple. Here are examples: berries, red and black grapes, red-skinned apples, red onions, red cabbage, purple broccoli and cauliflower.

And, though you can’t grow them here, be sure to include dark chocolate and coffee in your diet. They’re good for you, in moderation, of course!


• Birchwood Garden Club Plant Sale: 9 a.m.-noon. Saturday, May 2, at Bellingham Public Library, 210 Central Ave. Visit this annual favorite for some great plant deals and support the group that maintains the Bellingham Public Library’s beautiful flower beds.

•  Birchwood Garden Club’s May meeting: 7 p.m., Wednesday, May 6, Whatcom Museum, Old City Hall, 121 Prospect St.. Call 360-778-8930 for information. The topic of this month’s meeting will be “Rain Gardens with Janaki Kilgore.” Rain gardens offer stormwater management and water conservation in a highly adaptable format. Janaki’s company, Wonder-Flora, specializes in the field for both commercial and residential clients. She will be presenting the full rain garden package, including advantages, requirements, spectacular examples, setup and maintenance. Birchwood Garden Club’s membership is open to anyone in Whatcom or Skagit counties.

•  Using tunnels and hoop houses for productive gardening: 10:30 a.m.-noon, Saturday, May 9, Cloud Mountain Farm Center, 6906 Goodwin Road, Everson. Free. Call 360-966-5859 for information. You can grow great tomatoes and peppers in the Pacific Northwest. Use of high tunnels and hoop houses can bring you success in crops that often fail out in the open. We’ll discuss hoop house construction, planting, pruning and training, and management issues. No registration required. Be prepared to be outside.