Lettuce and Tilapia Aquaponics System [Simple Method]
Integration of lettuce and tilapia : The integration of Tilapia farming in intensive system and Lettuce production, called “aquaponics system” is practiced successfully growing in these countries [USA, Australia and Europe] and others. the residual water from intensive tilapia fish production provides sufficient qualitative characteristics for competitive production of lettuce without need adding commercial fertilizers.
Make money from Lettuce and Tilapia aquaponics
It’s quite possible to set up a commercial aquaponics business that is profitable from selling the Lettuce and Tilapia fish.
Many vegetables can be grown in water culture using nutrients either provided by chemical fertilizers (hydroponics) or produced by aquacultured fish.
- Aquaponics does not require soil.
- Can utilize marginal land.
- Supply both vegetable and fish.
- More room for local production!
- 89% of lettuce is imported
- 44% of fish is imported
The post describes an experimental setup to growing lettuce, shallow trays were constructed lined with plastic.
Lettuce plantlets were placed in small net pots inserted in holes in styrofoam panels suspended over the water by testing edges on the walls of the trays.
The lettuce roots took up nutrients in the trays from the water.
The nutrients were provided either by added chemical fertilizers or by effluent water taken from tanks in which fish were grown (plus some supplemental chemical nutrients added).
The water from the lettuce trays each time recycled to the fish tanks effluent water was added to the trays.
The only electrical component in the system was an air pump to aerate the fish tanks, providing the fish with oxygen and preventing denitrification.
Lettuce and Tilapia Aquaponics Setup:
- Lettuce tray corner, (2×6 side walls shown; 2x4s recommended). without plastic liner
- Lettuce tray with liner stapled in place, leveled with shims on hollow-tile support.
3. Spacing of holes in polystyrene panel
- Lettuce trays stocked with 2 week old lettuce seedlings
- Lettuce plants grow in net pots supported by poly- styrene panels. Roots extend down through an air space below the panels and into the water.
- Lettuce plants under a PVC frame covered with 50% shade cloth
- Developing Red Sails lettuce
- Lettuce seeds are sprouted in foam Oasis cubes and one cube is transferred to each net pot two weeks after sprouting.
- A cattle watering pan with biofilter.
Shade structure construction
Lettuce plants require partial shade to grow well in the warm climates found in Hawai‘i and other Pacific Islands, especially in the sunnier leeward areas.
In our experiment, lettuce grew well shade cloth under 50% .
Cross-section (width) showing elements of a lettuce tray
Read more about: Sizing and Placing Aquaponics System
Aquaponics Study in Hawaii:
- Hawaii is the leader in the field of aquaponics – 5 commercial farms
- For aquaponics to be an viable industry, we need to evaluate its economic feasibility
- Is aquaponics here to stay or is it just a fad?
Individual Farm Analysis
|Farm A||Farm B||Farm C|
|Location||Waianae, Oahu||Kunia, Oahu||Mililani, Oahu|
|Total raceway surface area (m2)||1070||1142||2657|
|Total fish production capacity (m3)||57||23||284|
|Types of vegetables||Lettuce||Lettuce||Lettuce, Tomatoes, Cucumbers, Beets|
|Types of fish||Tilapia||Tilapia, Chinese Catfish||Tilapia, Chinese Catfish|
Case Analysis: System Setup
- 4 independent aquaponic systems.
- Each system contain 8 vegetables.
- Raceways (35.67 m2) and one fish tank (18.93 m3).
|Number of days in nursery||14 days|
|Number of days in aquaponics raceways||31.5 days|
|Weight of a head when harvested||181 g|
|Harvest and delivery timing||2 per week|
|Number of days in breeding/nursery tank||105 days|
|Number of days in aquaponics tank||395 days|
|Weight of a fish when harvested||567 g|
|Harvest timing||1 per week|
Case Analysis: Baseline Results
|Annual production per unit area or volume||14.25 kg/m2||25.16 g/L|
|Annual production (kg)||16,248 kg||1,905 kg|
|Annual production (heads, fish)||89,549 heads||3,360|
|Cost and Revenue||Lettuce||Tilapia||Total|
|Initial Investment cost||$173,616||$43,462||$217,078|
|Annual operational cost||$52,406 ($3.23/kg)||$13,777 ($7.23/kg)||$66,183|
Case Analysis: Decision Reversal Analysis
|Lettuce Price ($/kg)||4.74 ( = $2.15/lb)||4.10 (=$1.86/lb)||-14.26%|
|Tilapia Price ($/kg)||11.02 (= $5/lb)||5.53 (=$2.51/lb)||-66.20%|
|Feed Cost ($/kg)||2.03||4.94||+83.65%|
|Feed Conversion Ratio||1.87||4.56||+83.65%|
- Small-scale commercial aquaponics is economically feasible.
- Economic outcomes are sensitive to the changes in output prices.
- Organic certification can double the price.
Lettuce and Tilapia ( Conditions, Growing, Production, Selling )
Aquaponics Lettuce Conditions:
- pH: 0–7.0
- Plant spacing: 18–30 cm (20–25 heads/m2 )
- Germination time and temperature: 3–7 days; 13–21 °C
- Temperature:15–22 °C (flowering over 24 °C)
- Light exposure: full sun (light shading)
- Recommended aquaponic method: media bed, NFT and DWC
Aquaponics Lettuce Growing (Harvest)
- Plant height and width:20–30 cm; 25–35 cm
- Growth time: 14–32 days (longer for some varieties)
- Number of days in nursery: 14 days
- Number of days in aquaponics raceways: 32 days
- Weight of a head when harvested: 181g
- Harvest and delivery timing: 2 per week
Aquaponics Lettuce production:
- Annual production: 25 kg/m2
- Annual operational cost: 23/kg
- Lettuce Price: 74 $/kg
Aquaponics Tilapia Conditions:
Tilapia fish are able to withstand a wide range of environmental conditions and high temperatures.
Including high salinity, high ammonia concentrations and low oxygen levels. This makes tilapia fish very suitable for aquafarming.
- Temperature: 17-25 °C
- Oxygen levels: 4 mg/L
- Optimal pH: between 6 to 9.
Tilapia can survive in pH ranging from 5 to 10
Ammonia: Must be less than 0.08 mg/L
The tilapia can tolerate high ammonia. Increasing ammonia concentrations increases the stress on the tilapia.
Nitrate: 27 mg/L
Nitrate concentrations should be below 27 mg/L for optimal cultivation.
Aquaponics Tilapia Growing (Harvest)
- Number of days in breeding/nursery tank: 105 days
- Number of days in aquaponics tank: 395 days
- Fish weight when harvested: 567 gram
- Harvest timing: 1 per week
Aquaponics Tilapia production:
- production: 25.16 g/L
- operational cost: $7.23/kg
- Tilapia Price: $11.02 /kg