Plant a Rainbow of Colors in Your Garden

When planting a vegetable garden, let color be your guide to healthy eating.  For a number of years, scientists have been discovering the health benefits of the color pigments in food.  For some gardeners, a vegetable garden is lettuce, collard, mustard greens and kale- all healthy, leafy green vegetables.   But for health sake, add some color such as red tomatoes, yellow squash and purple eggplant.  Grow a rainbow of colors to the garden for good health.

Red colored fruits and vegetables contain natural plant pigments called lycopenes or anthocyanins. These compounds may help reduce the risk of several types of cancer, especially prostate cancer. By the way, the lycopenes in cooked tomatoes with a small amount of fat are absorbed better than lycopene from raw tomatoes.  Sun dried tomatoes are reported to have twelve times the lycopenes as raw ones. So plant plenty of tomatoes, beets, watermelon and red peppers. If there is room in the garden, include a pigmented citrus tree like pink grapefruit. 

Orange and yellow colors come from natural plant pigments called carotenoids.  Beta-carotene is converted to vitamin A which helps maintain healthy eyes.  Carotenoid-rich foods can reduce the risk of cancer, heart disease and improve the immune system function.  Plant plenty of yellow sweet potatoes, squash, pumpkins and carrots.  Citrus contains hesperidin, also found in the skin of tomatoes, and naringenin, which are anti-inflammatory and antioxidant. Curcumin, found in turmeric, known in Hawaiian as olena, has antioxidant properties. Turmeric is a popular Indian spice used in curries and other dishes.  Anecdotal evidence suggests that turmeric can be used to deter ants in the garden.

Other yellow and orange fruits grown in Hawai`i are pineapples, papayas and mangos. Pineapples contain bromelain, an enzyme which aids digestion.  Papaya and tangerines contain beta-cryptoxanthin, another carotenoid, playing an important role in vision and in bone growth. Papayas can easily be grown from seeds or purchased in abundance at local markets.

 Greens are colored by a natural plant pigment called chlorophyll.  Some greens contain lutein which helps keep eyes healthy. Here is a familiar list of green vegetables: green peppers, peas, parsley, watercress, arugula, spinach and kale.  Crucifers like broccoli and cabbage contain chemicals which may help protect against some types of cancer.  Leafy greens such as spinach and broccoli are excellent sources of folate, which is a B vitamin. 

The blue and purple colored fruits and vegetables also contain pigments called anthocyanins, powerful anti-oxidants which improve brain function and help to reduce the risk of cancer, stroke and heart disease.  Fig trees grow well in tropical and sub-tropical climates and should yield delicious, healthy fruit.  Anthocyanins, also found in strawberries and raspberries, act as powerful antioxidants that protect cells from damage. 

The whites contain pigments called anthoxanthins which are shades of white or yellow.   This group consists of onions, garlic, cauliflower, turnips, mushrooms, potatoes and bananas.  At least one of the group, garlic, contains a health-promoting chemical called allicin. This compound may help lower cholesterol and blood pressure and help reduce the risk of stomach cancer and heart disease. Potatoes, as well as bananas, are good sources of potassium. 

Raised Bed Gardening - Pros and Cons

Many people are drawn to raised bed gardening for several reasons.  In addition to the fact some areas do not have sufficient soil, raised bed gardens generally look nice and appear easy to maintain. In many parts of the United States, reasons for building raised beds are to keep gophers out or to have warmer soils in the early spring after the winter thaw. For portions of the Hawaiian Islands, gardening in raised beds or containers is necessary because of a lack of soil on lava hardened  terrain.  

Other reasons for building raised beds are 
 (1.) the soil may be extremely alkaline (a high pH) or acidic (low pH), 
 (2.) the soil is too compacted,  
 (3.)  the gardener needs wheelchair access and
 (4.)  the gardener prefers less stooping.

On the other hand something to consider is the maintenance of raised beds. If the frame is made of wood, it will eventually rot. If metal is used, it may rust. Actual construction of the bed can be time consuming and costly. In addition to wood, rock and plastic can also be used.

Two questions often arise. First, how deep to make the beds?  The literature gives a range of 6” to 18”.  Crops like lettuce, onion and bok choy will do fine in a shallow bed. Yet deeper beds are needed for carrots, parsnips, corn and tomatoes.  

Secondly, where to get good soil? You can buy bagged potting mix at the garden store, which can be very expensive. Or you can buy a truck load of soil but be cautious. Soil may look good, but you can’t see N-P-K deficiencies or excesses, pathogenic fungi, bacteria, nematodes or pesticide residues including persistent herbicides. Bringing in soil can be risky.

Installing raised beds can be a satisfying project. But first, find out what your particular problem is and why you are considering a raised bed. Perhaps correcting the problem could be a better solution, possibly cheaper and less time consuming.

Photos from University of Missouri.