Photo Credit: Wikimedia Commons

Editor’s note: With this issue, we welcome H. Dale Sato to the pages of the Herald with a column titled, “From My Yard.” Anyone who raises fruit trees or vegetables in their own yard takes special pride in sharing their bounty with friends and family, usually making a point of emphasizing that the goodies are “From my yard . . .” And so we decided to name this column after that popular phrase, with the hope that the information contained in Dale’s columns will aid you in your own “yard-to-table” endeavors.

Dale has worked in the field of horticulture for over 50 years. As a teenager, he operated his family farm on the Big Island. He retired from a 30-year career as an extension educator with the University of Hawai‘i’s College of Tropical Agriculture and Human Resources, but remains involved in horticultural research and educational activities. We’re pleased to welcome Dale to our ‘ohana of Hawai‘i Herald contributors.

The warm days of summer have arrived, and I’ve been thinking about the sweet, juicy navel oranges and tangerines that my family grew commercially when I was growing up in Pähoa on the Big Island. I can even smell the sweet fragrance of the flowers that bloomed on the orange trees in the late winter and early spring months.

The cool night temperatures and volcanic soils of Puna produce the sweetest navel oranges in the state of Hawai‘i. These environmental and soil conditions make the fruits sweet and juicy.

Back in the 1950s, ’60s and ’70s, growing navel oranges was a lucrative business for farmers in Pähoa and other communities in the Puna District. Washington navel oranges were the main variety grown by the Issei and Nisei farmers, many of whom referred to the fruits as heso (Japanese for “navel”) mikan (orange fruit) —navel oranges.

Washington navel oranges were grafted onto rough lemon rootstock, producing fruits in three to five years. The trees were fertilized with 10-10-5 for vegetative growth. Later, as they were maturing, a fertilizer such as 5-10-10 was applied. In the 1960s, trees were fertilized with 10-20-20 or 7-14-14 a month or two months before maturity. Calcium carbonate or lime from Kawaihae, obtained through Ultramar — now fertilizer distributor BEI Hawaii, was applied every three to four years to correct acidic soil conditions. These days, fertilizers such as 16-16-16, or 8-8-8, which is an organic fertilizer, are applied twice during the growing season. Later, a fertilizer like 10-20-20 or 10-5-20 is applied about four to six weeks before the fruit matures, or in late September or October. As a rule of thumb, fertilizer should be applied at a rate of 1 pound for every 1 inch in tree trunk diameter per year.

I advise people to plant their navel orange trees about 15 to 20 feet apart and select grafted trees that are not root-bound. If it is root-bound, carefully spread the roots outward. It’s also important to replant the tree at the same soil level as its original container.

There are a few commonly made mistakes when planting citrus trees: Make sure that the tree isn’t planted too deep and that the roots are spread out if it is a root-bound plant. If not planted properly, citrus trees can remain dormant and not show any sign of vegetative growth for three to five years.

If your tree is planted in a hot, dry area, water it regularly two to three times per week. However, make sure that you don’t over-water it, especially if it’s planted in heavy clay soils.

Mulching the trees with well-rotted organic matter reduces weed growth and conserves moisture. Apply 2 to 3 inches of mulch around the drip line of the tree and about a foot away from the trunk.

We pruned our trees lightly every year after the last crop of the season was harvested, usually in late December and January, trimming away dead and excessive branches. Citrus trees can grow to be 20 feet tall and pruning kept them smaller and easier to harvest. Around February-March, sweet-smelling flowers that were white-orange in color covered the trees, attracting swarms of honeybees.

By mid-September, the fruits slowly began to turn color. Those appearing at least a quarter ripe were harvested by twisting the fruit slightly. The fruits were then placed in denim bags and later transferred to burlap bags, filling them until they held about 50 pounds.

The oranges were sorted by size — small, medium and large. Those fruit damaged by Oriental fruit flies were separated and shared with friends. Since most of the fruits had a bronze casting on the rind caused by mites feeding on the rind, the fruits were labeled as “Hawaii Number 1 Bronze.” In Hawai‘i, the fruit rarely has a deep orange color to the rind.

The navel oranges were finally placed in onion bags that had been turned inside-out so that the onion brand could not be seen. Each bag weighed 50 pounds. The top of the bag was sewn with sisal cord and later, with poly cord, using a curved needle. The fruits were then delivered to Hawaii Produce, Farmers Exchange or Mukai Store. In Pähoa, Isamu (Ikali) Iwata of Big Island Produce picked up the bagged navel oranges from the growers and shipped them to produce wholesalers like Fukunaga Brothers on O‘ahu.

Growing navel oranges became a challenge in the late ’60s when an infestation of greenhouse whiteflies was discovered. The whiteflies left the tree leaves and fruits covered with a sooty mold that even spraying with dormant oil sprays didn’t help. The fruits needed to be wiped or scrubbed to remove the black soot-like substances before sending them to market.

Another problem was the Oriental fruit flies. Female flies oviposited into the fruit rind, causing the fruits to ripen prematurely and rot. To minimize the fruit fly damage, growers used Staley’s protein yeast bait as well as methyl eugenol as a male attractant. Nowadays, GF 120, methyl eugenol, and good old sanitation and education are employed to minimize Oriental fruit fly damage.

In the past decade, pests such as citrus black fly, citrus leaf miner and Asian citrus psyllid have been detected. Most of these pests can be kept in check with parasitic wasps. Also, keeping the plants fertilized and watered on a regular basis helps strengthens the plants’ ability to cope with pest problems. Insecticides containing imidacloprid will control most of the insects attacking citrus trees.

There are many different varieties of navel oranges available these days, including the standard Washington navel and many sports of this variety, including Frost navel, Robertson Navel, Thompson Navel, Fisher and Lane Late. Varieties are grafted onto rootstocks such as Heenaran mandarin, Cleopatra mandarin and Troyer citrange and dwarf root stock such as C 35. Another navel orange is the Rico #3, which is a sport of Washington navel. It has very good qualities. Texas Joppa, Shuekhan and Rarotonga Seedless, which is a good juice orange, are harder to find, but good citrus trees, nevertheless. If you want a less acidic orange, try the Tabata navel orange. There’s also Cara Cara, a reddish-purplish-fleshed navel orange.

Some of the harder to find citrus varieties are available on O‘ahu at Frankie’s Nursery in Waimänalo and at Da Garden Shop in Waipahu. Plant It Hawaii, a wholesale fruit tree nursery in Kurtistown on the Big Island of Hawai‘i, also has a good selection of citrus trees that are available at many garden centers. Additionally, multiple grafts of citrus with navel oranges and other species are available at plant sales held at the University of Hawai‘i’s Urban Garden Center in Pearl City.

Nowadays, you can often find Kä‘u oranges, which is a Washington navel orange, in supermarkets. They have qualities similar to Puna oranges. Kapoho oranges, another navel orange, is available at farmers markets.

Next time you are shopping for fruits, consider buying our locally grown navel oranges. They might not win a beauty contest, but they’ll take the prize for juicy and sweet-tasting. And if you love fresh-squeezed orange juice, nothing is better than Hawai‘i’s navels. Mmmmm . . .



  1. Hi. I have a healthy dwarf Washington Navel Orange tree about 8 years old. The fruit are large and yellow, but when I cut them open, the inside is pure white, dry, and have no taste. Occasionally, I would get one that has orange, sweet flesh. Some have flesh that is ripe on the bottom, but white at the top. I leave all my fruit on the tree till they fall off on their own.
    I have a problem with birds eating the fruit, so I wrap each fruit in a clear plastic bag. Do you think this is affecting the fruit? I would appreciate any advice you may have. Oh, I live in Niu Valley.


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