The Ultra Quick Guide to

Starting a Spirulina  Farm

The following guide is intended for starting a scalable spirulina production environment that relies on simple technologies that are relatively low cost and easy to setup.  

Step 1: Construct your Open Raceway Pond

First, find a spot for your raceway pond. Be sure to have plenty of sunshine and about 30% shade for the warmer days. To construct your raceway pond, dig an oblong shape, size between 10-300 meters long and 1-20 meters wide. Create ridges to divide your pond into parallel channels of about 1 meter wide each, and leave the edges open to allow water circulation, like in the image below. You can adjust the length of your pond according to how much space is available. The depth should be no more than 0.5 meters (or 1.64 feet). Be sure to install a drainage system so you can empty the pond in case something goes wrong.

The Ultra Quick Guide to Starting a Spirulina Production Farm- spirulina network
Raceway ponds are a popular solution for growing spirulina in the open air. They are easy to build and maintain and require only minimal investment. The circular shallow structure of these ponds makes it easy to agitate the water, providing maximum sunlight exposure even to the smallest spirulina cells.

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spirulina open raceway pond liner PVC

Contact us if you need assistance with constructing your raceway pond. Our pond construction experts will be happy to provide tips and advice, or come to your location and do it for you.

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Step 2: Line your Raceway Pond

You can choose whether to line your pond with concrete, clay, or a pond liner made of durable plastic like PVC. If you choose the latter, you can ask your PVC supplier to sew the pond liner according to your measurements, which will significantly reduce the chances of leakage. Either way, if you're inexperienced with construction projects it is advised to hire a professional at this stage. 


Step 3: Install a Paddle Wheel Aerator

Paddlewheel aerators are an excellent choice for medium and large ponds where movement of oxygenated water away from the aerator is most important. There are many paddle wheel aerator designs that can be purchased as an off-the-shelf solution, or be built DIY to address your specific requirements. You can connect a number of paddle wheels to one central motor and place them in parallel ponds for higher efficiency.

The motor-driven paddle wheel aerator should be backed into the water so that the axles are parallel to the water surface. The most effective way for this aerator to operate is when the paddles are turning at 108 rounds per minute (RPM), 21 inches deep. The paddles should turn toward the bank, forcing the water out into the open pond with a violent agitating action.

The Ultra Quick Guide to Starting a Spirulina Production Farm- spirulina network
The Ultra Quick Guide to Starting a Spirulina Production Farm- spirulina network
Now that your raceway pond is filled with water, use our calculator to know your exact water volume. This will help determine the mineral proportions when preparing the culture medium.

Step 4: Fill your raceway pond with water

  • Fill your pond with water from a clean source, preferably natural spring water, rainwater or melted snow.
  • Though not ideal, It's actually OK to use tap water. Normally clean tap water will have trace minerals, as well as calcium which can be good for spirulina growth. You should however consider the levels of Chloride (<15), Fluoride (<20) and Hardness (<200) when calculating nutrient proportions.
  • If you choose to use tap water and you don't want to change nutrient proportions, let the Chloride evaporate for about 12 hours before adding the culture medium.

Stage 5: Choose your Preferred Culture Medium Formula

The culture medium is the nutrient mix on which your spirulina will feed in order to thrive and reproduce. It is well known that as a detoxifying agent, spirulina will consume whatever nutrients are available, including toxins and heavy metals. As spirulina doesn't need organic materials for its reproduction, the debate over organic Vs. non-organic becomes irrelevant; and yet, you will come to learn that some chemicals are better for your health than others. We therefore strongly advise you to use our Spirulina glossary and educate yourself with regards to the different formulas available, so you can make a wise choice. 


The Ultra Quick Guide to Starting a Spirulina Production Farm- spirulina network

Below is a collection of culture medium formulas which we gathered from different parts of the world, on our quest to find the ultimate and most effective ways to grow spirulina. 

Step 6: Add Nutrients to Your Raceway Pond

Run the agitator to get the chemicals mixed up properly. This can either be done with a paddle wheel agitator or an air pump. Ideally, you'd have an electric timer to set the agitators on and off.

Add the nutrients according to the recommended proportions of your preferred culture medium. The majority of formulas require 1 liter of mother culture for each 1000 liters of nutrients, after they were mixed in the water. When you're done, run the agitator in cycles of 15 minutes every hour. Don't add any other chemicals and continue to agitate for 10-12 days. On day 12, your pond should be concentrated with dark green spirulina, and ready for harvest.


To be on the safe side, remember to save some of the culture aside, just in case something goes wrong.


Step 7: Harvest your First Batch of Spirulina

On the 13th day, your culture medium should appear dark green, with a relatively thick texture. You can now perform your first Spirulina harvest.

Place a 30-50 microns nylon mesh above your growth tank and pass the liquids through it until a thick jelly-like paste is formed on the top. Use a water pump to make this process easier, and place a piece of fabric at the edge of your hose to collect unwanted particles like leaves or insects.

Rake the wet biomass to the center of the mesh, then place inside a harvesting close and squeeze out the excess water, keeping only the freshly harvested spirulina. Now wash your mesh in clean water and pour back to the pond to avoid wastage.  


Step 8: Feed the culture after each harvest

We determine the amount of nutrients added after the harvest according to the weight of the dried yield. If you don't want to dry your Spirulina, this can be calculated in a ratio of 10% of the biomass weight. For example, if you harvest 1kg of fresh biomass, the dried weight will be 100 grams. Each feeding formula has slightly different proportions. Use our After Harvesting Feeding Calculators to determine which nutrients to add and in what proportions.   

The Ultra Quick Guide to Starting a Spirulina Production Farm- spirulina network

grow spirulina FAQ

Step 9: Familiarize yourself with common problems

Especially if you're a beginner grower, it is not uncommon to encounter difficulties. Such problems may include:

  • pH going too high or too low
  • Sudden changes in color
  • Floating clumps
  • Excess residue
  • Intrusion of another algae
  • And more

Use our Spirulina FAQ to search for answers to common problems, or join one of our whatsapp groups to seek advice from other members of the Spirulina Network. 

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