Algae should make up around 20% of soil microbial biomass.  Algae are just as important to the ecosystem of your soil as bacteria and fungi!  Life in your soil is created by these three groups of microorganisms.  But what do you know about soil algae?   Here are the highlights of what algae does for your soil:

Algae make bioavailable nitrogen out of thin air!!!

Using cyanobacteria, aka blue-green algae,  to add nitrogen to soil is a carbon neutral choice for gardeners.  Blue-green algae fix nitrogen without the energy expended in high temperature and pressure processes to make industrial urea.  Algae are solar powered and can be grown right next to the crop being fertilized.    Cultures of cyanobacteria can be added to your soil to seed their populations and start the process of nitrogen fixation.  Algae keep it simple and local.

Algae provide oxygen to the soil ecosystem.

Algae perform photosynthesis in the soil producing oxygen.  Oxygenation of the soil supercharges the soil ecosystem!  Diffusion of atmospheric oxygen through soil is slow, so having a oxygen generator in the first two-inches of soil supplies vital gas for the bacteria and fungus to do their jobs.  Fungi and aerobic bacteria need a good supply of oxygen and algae can play a key role in supplying that vital molecule.

Soil Algae can prevent algae blooms in your local watershed!

A key to algae bloom prevention is to limit nutrients from entering the watershed, which can be accomplished by having healthy soil algae populations on land. Algae are fertilizer sponges.   They can take up more nutrients they need in a process described as “luxury uptake”.   The microorganisms lock away nitrogen and phosphorus into their biomass and distribute it to several generations of offspring.

The goal is to feed the algae in the soil, not the water.  With a healthy soil algae population, you can absorb fertilizer runoff into your soil.   Over time Soil algae will re-distribute the nutrients back to your crop, while water algae will bloom then stink up the ponds and kill all the fish.

Should I culture my own soil algae or buy a culture to seed my soil?

Your soil probably already has algae in it.  You can culture your own with a Soil Algae culturing kit.  It is a simple process that will take some time and patience, but the reward is healthy soil fertilized with algae from your backyard.  After you have several gallons of culture you can start to distribute it onto your soil.  The benefit of a few weeks of adding soil algae to your yard can be comparable to a years worth of a legume cover crop.   Would your raised bed garden be up for a microbial turbo-boost?

If you think your soil is lifeless, you can add live culture directly to it.  Each liter of concentrated soil algae should handle roughly 10-square yards of earth.  Thoroughly wet the soil then add it evenly with a watering can.  Keep it wet for a few days to give the algae a chance to establish themselves.

A great resource for all things Soil Algae is to visit SoilAlgae.com. They can provide you with cultures and culturing kits for all soil types.  SoilAlgae.com has been culturing algae for almost 20-years and know how to help.