Tropical Gardening Helpline: 9-17-17


Lorraine asks: I have heard that growing veggies aquaponically is actually a good way to reduce water consumption. Is that true? If so, how can I get an aquaponics system started?


Lorraine asks: I have heard that growing veggies aquaponically is actually a good way to reduce water consumption. Is that true? If so, how can I get an aquaponics system started?

Tropical Gardener answer: It is true that an established aquaponics system requires very little additional water. Once you have the fish tanks and growing tables set up and filled with water, you should only need to add a small amount of water periodically to replace what has evaporated or been lost in plant transpiration. Most aquaponics systems use about 10 percent of the water that would be required for a similar sized garden grown in soil.

An aquaponics system is made up of a tank containing fish and growing beds for vegetable plants. The water from the fish tank enters the growing beds that are filled with gravel or clay pebbles or with floating rafts to hold the plants. The plants take up the nutrients and whatever water they need as the water is recirculated through the system. The fish supply nutrients to fertilize the plants and the plants clean the water of the nutrients before it returns to the fish tank.

The concept is simple and small do-it-yourself systems can be created by backyard gardeners. Some knowledge of aquaculture, horticulture and plumbing can help you build a successful system. Several sources here on the Big Island can also help. Zac Hosler is currently expanding his Living Aquaponics farm in South Kona but is still available for classes and consultations. Contact him at to find out how he can help. Friendly Aquaponics in Honokaa also offers classes and instructions. Their book “Aquaponics: The Easy Way” is available as a free download at

This Saturday, Friends of the Library in Kona (F.O.L.K.) are sponsoring a talk on aquaponics by Vernon Byrd as part of the series of monthly events presented in conjunction with their Community Seed Library. The talk will begin at 10 a.m. at the library at 75-138 Hualalai Road in Kailua-Kona. You can contact the library at 327-4327 if you have questions about the presentation.

Vernon is currently the leader of the technology and science group at the University of the Nations in Kona. Aquaponics is one of the technologies they demonstrate and teach on their campus. In his presentation, Vernon will explain the basic concepts of aquaponics and discuss the different types of beds, the selection of plants and fish as well as management issues. He will also cover outcome expectations and operational costs. Anyone interested in aquaponics or with aquaponics systems in place may want to take advantage of this opportunity for free information and the chance to ask questions and get answers.

Email plant questions to for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.

Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.

Gardening Events

Friday-Monday: “Facing Challenges: 27th Annual Hawaii Tropical Fruit Growers Conference” at the Kaikodo Building at 60 Keawe Street in Hilo from 5 p.m. dinner on Friday and talks starting at 7:30 a.m. through 6 p.m. dinner on Saturday. Tour of OK Farms in Hilo from 9 a.m. to noon on Sunday. Tour of Ken Love’s farm from 9 a.m. to noon on Monday and HTFG meeting with speakers from 6 to 9 p.m. Monday evening at the HTFG Kona office 81-6393 Mamalahoa Highway in Kealakekua. Conference continues on other islands during the following week. For information or to register go to Contact Ken Love at or 323-2417 with questions.

Saturday: “Hawaii Seed Fest: Local Seeds for Local Needs” from 9 a.m. to noon at Kawanui Farm in Honalo. Meet seed savers and learn about conducting local seed trials. This is a free event sponsored by the Hawaii Seed Growers Network. Space is limited. Register by Sept. 21 at or call The Kohala Center at 887-6411 or go to and follow the link to Eventbrite. Directions to the farm will be given upon registration. For more information, contact or 322-2801.

“Friends of Amy B. H. Greenwell Ethnobotanical Garden Annual Meeting” from noon to 4 p.m. at Amy Greenwell Garden in Captain Cook. Free tours of the garden starting at noon. Pupus and a short member meeting at 2 p.m. and a 2:30 p.m. talk by world renowned coffee and tropical horticulture specialist, Dr. Krishnan of the Denver Botanic Gardens. For more information email or call Peter Van Dyke, garden manager, at 323-3318.

Farmer Direct Markets

Wednesday: “Sunset Farmers Market” 2 to 6 p.m. in the HPM parking lot at 74-5511 Luhia Street in Kailua-Kona (across from Target)

Wednesday &Friday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Friday: “Pure Kona Market” 9 a.m. to 5 p.m. at Amy Greenwell Garden in Captain Cook

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

Sunday: “Pure Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook

Tuesday–Saturday: “U-Pick greens and produce” 10 a.m. to 4 p.m. Tropical Edibles Nursery, Captain Cook.

Plant Advice Lines


Anytime: Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892

Mon., Tues. &Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or