Resources from the Introduction to Aquaponics and Aquaculture course taught by Dr. Robert Howerton
Water Quality Publications
Nitrite in Fish Ponds
Ammonia in Fish Ponds
Interactions of pH, Carbon Dioxide, Alkalinity and Hardness in Fish Ponds
Measuring Dissolved Oxygen Concentration in Aquaculture
Carbon Dioxide in Fish Ponds
Managing High pH in Freshwater Ponds
Managing Ammonia in Fish Ponds
Seeds for Aquaponics
You may trial different varieties in your aquaponics system to see what does best in your system and then let selected plants go to seed and save and replant. The 2 main plants which are easier to try are lettuce and tomato (sometimes peppers). These vegetables have “perfect flowers” which means they are self pollinating (hot peppers however are out-crossers and will cross pollinate with sweet peppers. Therefore, do not grow them without proper isolation). You can save seed from 5 to 10 plants of open pollinated varieties to maintain genetic diversity. Where you are located will affect how your plants grow. Temperature and day-length can play a large factor on success or failure. Although we have a relatively stable day-length in Hawaii we do get enough variation from summer to winter to pay attention to day-length sensitive plants and grow them in the proper season. When growing lettuce in warm areas or in summer you may want to choose varieties that are slow bolting.
Recommended varieties include:
Lettuce (these are all open pollinated varieties)
Nevada – best heat tolerant, slow bolting, has a thicker leaf.
Little Gem – small compact head, slow bolting except in the warmest areas, then grow in winter).
Merlot – red leaf color with open leaf
There are many other varieties that are worth trying to determine what grows well for you.
Tomato – (these are all open pollinated varieties)
Healani – determinate – a medium sized tomato
Komohana – indeterminate – a quarter sized cherry, thicker skin good flavor
(Source: UH seed lab; both open pollinated and best grown under cover out of rain to avoid disease but these are the best disease resistant for the tropics)
Diva – Johnny’s seeds. Hybrid – Self pollinating. Good for covered areas where pollinators have no access so there is no need to hand pollinate.
#9 – UH Seed Lab CTAHR. Open pollinated. Grow in summer in gravel beds. Must be staked to keep from toppling over.
Lemon basils do very well in the tropics and can withstand wetter conditions.
Genovese – Tends to get black spot when exposed to wet or humid weather
Thai Basil – Tends to get black spot when exposed to wet or humid weather
Kala – UH CTAHR Seed Lab – open pollinated – Pimento type, sweet and meaty.
Banana – small yellow pepper, prolific and long producing – look for open pollinated varieties if you want to save seed.
Both have good disease resistance but do not like to be exposed to wet conditions.
Celery – Tango is a good variety. It will not go to seed in the tropics without a winter chill period (vernalization). Best grown in cooler months.
Others to try in gravel beds
Taro (in gravel beds), peas (in winter months) mint, parsley, green onion, garlic chives, cilantro (best in winter, bolts in summer), arugula (best in winter, better in gravel beds, bolts in summer).
Broccoli, cabbage, kale (Red Russian) – best in gravel beds
Cabbage will not go to seed in the tropics without a winter chill period (vernalization).
Shiso will grow very well in raft beds and gravel beds – if grown in winter it will put its growth into going to seed. Grow in summer for good leaf production and ability to pinch back and re-grow. It could be a good specialty crop and is easy to grow,
You may purchase seeds from UH Seed Lab CTHAR. You can download a seed order form at http://www.ctahr.hawaii.edu/seed/Downloads/Seed Order Form.pdf . Most varieties are adapted for tropical environments and disease resistance.
When ordering from mainland seed companies, look for seeds that are from warmer climates or from the South as they may perform better in our tropical environment.
Do not save seed from Hybrid varieties, they will not grow true to type. Save seed only from open pollinated or heirloom varieties. By saving seed from your aquaponics system you may select for those plants that do well. As you save seed generation after generation the variety will become better adapted to your aquaponics system and over time can improves with seed generations.
The Hawai‘i Public Seed Initiative, a program of The Kohala Center, is currently developing an online variety selection tool using data from growers across the islands on what does best in their locales. This tool will be online soon.
Lyn Howe, Coordinator
Hawai‘i Public Seed Initiative, A program of The Kohala Center