Aquaponic - Microgreen and Sprouting System
Microgreens - Tiny edible plants that are older than a sprout, but younger than a full-grown plant. Microgreens are harvested after the first (true) leaves have developed.
Nutrients measured in Microgreens, are as follows -
· Ascorbic acid (vitamin C).
· Tocopherols (vitamin E).
· Phylloquinone (vitamin K).
· Beta-carotene (a vitamin A precursor).
Plus other related carotenoids in the cotyledons.
Further plant use -
Microgreens! for planting on (until mature) Ether acquaponic or soil based planting.
(This will be more appropriate, as the costs for harvesting young crops for consumption would be rather expensive).
Grain Sprouts! For animal feed, and planting on (for agricultural soil based planting).
Growing media - Coconut Coir – Should be widely available in Cambodia.
(I would be looking at course matting, and developing grow plugs with the material).
Fish-Tilapia - Commercial tilapia farms will usually feed their fish pellets made from fishmeal, grain, soybeans or other food products. In the wild, tilapia will eat vegetation, algae, plankton, insects, larvae, decaying organic matter, fish wastes, small fish and just about anything edible that they can get in their mouth.
System water - Collective rainwater.
The pH of collective rainwater is between 5.5 and 6.0 because of carbon dioxide that's dissolved in the atmosphere. (Rainwater is ideally suited for the system).
Introduction to the pH scale
The colours observed in solutions when universal indicator is added
The pH scale is a measure of the relative acidity or alkalinity of a solution (see diagram).
So, knowing the pH of a solution, you know how acid or alkaline it is by reference to the pH scale (diagram above) or whether the solution is neutral.
The smaller the pH number, the more acid it is, the greater the pH number, the more alkaline it is, and if the pH is close to 7, you have a more or less neutral solution that has neither acidic or alkaline chemical properties.
System pH levels - Maximum nutrient absorption rates would work well at around 5.5 to 6.8. (for the planting I have recommended for this system).
Plant growing- For example
Tomatoes, Peppers and Cucumbers are all flowering plants and prefer slightly more alkaline water.
Lettuce, Basil, Swiss chard and or green leafy plants are much happier in a slightly less acidic solution.
Altering pH levels - For gentle buffers that provide potassium and calcium I would recommend potassium bicarbonate and calcium carbonate. Be sure to only use small quantities at a time since you don’t want to raise your pH much.
A simple way many people will add calcium carbonate to their system is to put some shell grit or limestone chips into a mesh bag or some stockings and hang them in the tank. If the pH value, rise too high in the system, you can pull them out for a while till the pH starts to drop again.
Potassium bicarbonate can also be used mixed with water to spray on plants to combat certain moulds and mildews.
Nutrient Shutdown - This occurs when the pH is way too high or low and the plants cannot absorb the nutrients in the system. Plants will start to wither, show signs of leaf curl begin to yellow, have stunted growth. In effect, the plants are starving to death.
New System build proposed –
Settling basin - Separating solid wastes and uneaten fish feed.
Bio filtration - Pollution control of the system.
NFT System - Nutrient Film Technique. This is a hydroponic irrigation technique, where a flow of water containing all the dissolved nutrients needed for plant growth is circulated through the plant roots. (Clear irrigation pipes and Coconut Coir filled grow beds).
Fish will be raised in fresh clear rain water. The water will flow into the settling basin. Then will be pumped into the planting system and returned to the fish tanks via the Bio filtration bed.
The system will be low water flow, due to N.F.T and slow flood and drain beds. The system will be nutrient-rich, providing bio-security and food safety.