Lichen Growth Formulas

How to Grow Lichens

The lichen lovers have tried a lot of lichen growth formulas. The most successful and easy to implement are listed on this page. We recommend one application a year near the beginning of a rainy or snowy time, but if you've missed damp weather go ahead and apply the growth formula anyway.

If locally collected powdered lichens from a similar microenvironment are put on the surface before the formula dries, the proteins in the formula act as a (somewhat waterproof) glue to hold the lichens in place, especially on limestone rocks. While lichens often seed themselves you'll get much better results is you plant some too.

Formula 1 (Traditional)

cultivating lichens with milk The first method we tried, and the most commonly practiced lichen growth formula is to spray or paint milk, yogurt, or rice water onto the surface where lichens are desired. This will usually darken the surface in a matter of weeks or months, and within a few years many lichens often appear. We prefer fresh milk in a spray bottle for the ultimate ease of application.

Formula 29 (Magnificent Lichen Growth Formula)

Mix the following together and bring to a boil stirring frequently:
  • 1 pint milk
  • 1 teaspoon flour
  • 1 teaspoon yeast
  • 1/2 teaspoon gelatin
  • 1 tablespoon green algae powder (Spirulina or chlorella may be obtained from the vitamin department at some grocery stores. Pet stores may carry fish food that is mostly algae.)
  • 1/16 teaspoon water soluble fertilizer with micronutrients (bloom boosting formula preferred, such as 15-30-15 or similar, NOT acid loving formula.)
Remove from heat as soon as boiling commences, and cool to room temperature. The formula may be stored a few days in the refrigerator.

Immediately prior to application, add:

  • 2 teaspoons of lichen flakes collected from common lichens growing in a similar microenvironment to where the new lichens are wanted.
  • 2 teaspoons of healthy soil collected from an area near where lichens are currently growing.
Shake or stir well.

Use a paintbrush to apply this solution to the areas where you would like new lichens to grow. Apply as soon as practical after making the formula since this is a living, very bioactive mixture. For best results do not apply during a rain storm, or when rain is expected within a day.

Purpose of Ingredients
The proteins in milk interact with Calcium in the environment, in the soil, and in the rock to form a somewhat waterproof glue to hold the mix in place.

The flour, yeast, green algae powder, and fertilizer act as nutrients to either the algae or fungi or both. (Ever notice how fast mold fungi grow on moist bread?) Our interest in these ingredients is to extract the nutrients from them, not in having them grow on the rock. Any form of yeast, flour, or algae is acceptable. Substitutions are appropriate and the lichens won't die a horrible painful death if you leave something out. (No nerves = No pain)

The soil acts as a nutrient, and helps to set the proteins in the milk, and may contribute algae, fungi, or lichen spores.

The gelatin helps to waterproof the formula and keep the nutrients and young lichens from washing away. Gelatin may also be somewhat detrimental because it sheds rainwater that might otherwise be absorbed by the stone. A splotchy application can help minimize this issue.

We intend to investigate the addition of clay and/or silica gel and/or water crystals and/or other ingredients that might improve the ability of the mix to capture or retain water.

In areas where acid rain is a problem powdered limestone may be added to the mix to neutralize the acid.

In 2008 we started an investigation dealing with the addition of mushroom powder and specific sugars into the magnificent formula. It is showing great promise. Only trouble is, what do we call a formula that is better than magnificent?

Choosing a location

In addition to nutrients lichens require light and moisture for growth. Lichens tend to grow best on rough porous surfaces that retain moisture. In northern latitudes the north facing sides of objects tend to support lichen growth much better than south facing sides because they remain damp longer after dew or rain. Cracks and crevaces are also favored places for lichen growth because of the increased dampness.
Other Formulas

If you have a favorite formula that you would like to share, or if you have tried one of these formulas or a different formula, please write lichen@lichenlovers.org and let us know how it worked for you. Please include details about where and when you tried your experiment.

We are always trying new formulas, and modifying existing ones. (It took 29 attempts to arrive at the Magnificent Formula.) When we find new and exciting ways to encourage lichen growth we will post them here.

We have heard about the sugar water formula (1 Tablespoon sugar per pint of water) but haven't had time to evaluate it yet. Can anyone tell us how it worked for you?

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