Preparation

Before you buy anything, work out which strain you want, what you will grow it in, and whether you need a heater and a light. This page answers those four questions.

Which culture should I grow?

Which strains are good for the classroom?

We like reliable, fast growing strains that are not fickle and not invasive. None of our strains are invasive. A few of our favourites are below. Our Algae Beads kit is a good alternative to growing free living cultures, and our Brainy Brinys kit is an excellent model predator-prey system.

One of our favourite freshwater strains is spirulina, a blue green extremophile that prefers high pH, around pH 10. That pH is an advantage, because it limits competition from other algae and frees you from worrying about contamination. They are giants in the microbe world, which lets you harvest them with a simple mesh screen. They are non-toxic and eaten around the world for their protein and antioxidant properties. Our Spirulina Culture Kit is here.

Chlorella is another hardy freshwater species, and it is the one we use to make our Algae Beads. Our Chlorella Culture Kit is here.

For seawater projects we recommend Nannochloropsis. It is a small, hardy plankter at 2 micrometres, it grows very quickly, and it responds to changes in salinity, nutrients and toxins with matching changes in biomass. That makes it excellent for experiments. Our Nannochloropsis Culture Kit is here.

Which strains are best for research projects?

Favourites: spirulina, Nannochloropsis, and Chlorella vulgaris.

Consider your research goal. Choose a strain that best emulates your system: freshwater or seawater, diatom or dinoflagellate, green or blue green. The most important thing is that you want to test your hypothesis, not test whether you CAN grow algae. So choose a strain that is not going to be troublesome to grow and that lets you draw conclusions relevant to your hypothesis. Browse our Organisms page to find the one that fits.

Which strains of algae do people eat?

People eat spirulina, Chlorella vulgaris and Chlorella pyrenoidosa. However, we recommend buying algae to eat that is packaged for that purpose. We at ARS offer no guarantee, warranty or prediction of safety if algae we sell is consumed by humans or animals. While these strains are routinely eaten, quality control systems are in place to make sure they are safe. Our strains are clean and reliable, but once it leaves our doors, all bets are off.

Oh, and please do not call us and ask how much urine you should use to culture spirulina, because we have been asked before and the answer is none.

Which strains are best for feeding to aquariums?

• Seawater favourites: Isochrysis, Nannochloropsis, Tetraselmis, Porphyridium and Thalassiosira. And of course brine shrimp.
• Freshwater favourites: Chlorella vulgaris, Chlorella pyrenoidosa, Navicula, and spirulina, though you will need to wash the spirulina to remove its extremophile media.
• Feeding filter feeders? Find the size class your filter feeder can strain from the water, and get a feed it can actually capture.
• Improving water quality? You want a fast grower with a high capacity for luxury uptake. Nannochloropsis is your algae. It grows fast, gobbles up the excess nitrogen and phosphorus, and then gets eaten or grabbed by your filter.

Which strains represent algae blooms?

Favourites: Anabaena, Nannochloropsis, spirulina, dinoflagellates, Chlorella.

To study algae blooms you need an alga that will reliably grow, and all of those will. Anabaena is a blue green alga commonly found in lake blooms. Chlorella is another freshwater strain, less often a problem in the wild but it grows very well. Dinoflagellates such as Prorocentrum are marine, and dinos are commonly part of nearshore blooms. Most strains can model a bloom. Pick one and justify it in your paper by saying it is easy to grow and comes from an appropriate group of algae.

What kind of container should I use?

Containers for experiments

• Centrifuge tubes, 50 mL. For small cultures. Inexpensive, self standing, easily moved, completely reusable.
• Beaker Bags, 500 mL. For larger volumes. They stand up on their own and are reusable. 500 mL is a good volume for growing brine shrimp.
• Empty water bottles. Great. It feels good to recycle, doesn't it. Keep the lids open for gas exchange.
• Tissue culture flasks, 50, 250 and 600 mL. Some of our favourites. Useful for getting cultures close together under a single light source. We suggest the vented cap versions.

Containers for large cultures

• 10 gallon glass aquarium. Easy to buy locally from a pet shop, and shipping one is not recommended. This is the workhorse of many a lab and classroom. After your algae project is over, we recommend goldfish.
• Aquariums larger than 10 gallons. Growing to 10 or 100 gallons. Useful, but now you are limited by how much light can pass through the culture. Mix well so every cell gets its turn in the light.
• Ponds, 100 gallons and up. Covered or open. This is where most of the world's algae is grown. Any ideas on how to cultivate at sea? It is our goal to reduce CO₂ in the atmosphere. Call us if you have a good idea. We want to believe.

Do I need a heater?

Probably yes, maybe no. Most strains do well at temperatures humans find comfortable. Between 21 and 32 C, that is 71 to 90 F, you get the best response from most of our strains. Each strain is a little different, which is itself a great research project. Higher temperature means faster growing algae, so if you are in a rush, warm it up. You know who I am talking about, high school science project student.

Too hot is over 100 F. Most algae die promptly at 104 F. It is best not to tempt fate.

Do I need a light?

Yes, you will need light of some kind. We recommend LEDs or CFLs on a 12 hour timer.

Aim for 100 to 300 micromoles of photons per square metre per second. Most phytoplankton saturate around 120, meaning extra light beyond that buys you very little.

We wrote two longer pieces on this: How much light do I need for my algae? and Lighting for Algae Cultures.

Do I need salts and nutrients?

Yes. You need both salts and nutrients to grow algae.

Salts

Think of the salts as the physical environment for the culture. Even freshwater cultures need some salts. Salts generally include chloride, sodium, magnesium, sulphate, calcium and potassium. We make our culture salts with pH buffers so the culture resists swings in pH, because photosynthesis pulls CO₂ out of the water and drives pH up.

Our blends: seawater at 30 g/L, Brainy Briny at 40 to 45 g/L, spirulina and alkali at 15 g/L, freshwater at 1 g/L.

Nutrients

Most people are familiar with fertilizer for their gardens. This is very similar, but formulated for algae rather than terrestrial plants. Our nutrients are custom blended and work in both freshwater and seawater cultures. Dose at 1 mL per litre.

Media

Media is what we call the finished mixture of water, salts and nutrients.

What does a setup look like?

You need six things to get a culture going:

• Culture
• Container
• Salts
• Nutrients
• Light
• Heater, if your room gets cold

I am ready to start. What next?

Our full culturing guide walks through setup, inoculation, measuring growth and troubleshooting, all in one place.

How to Culture Algae

Or go straight to Starting a Project.