Although not as important as monitoring the biomass and quality of your kelp, collecting some environmental data on a routine basis can help paint a more detailed portrait of your farm over time.

Salinity

Salinity can be measured with an inexpensive salinity refractometer, commonly used at commercial aquariums, and available online. You can easily read the salinity of the water by putting a few drops onto a slide and holding it up to the light. The reading will display the salinity in parts per thousand. One reason to check salinity, especially after heavy rainfall or periods of intense snowmelt, is that freshwater can cause a blistering effect on your crop that might make your kelp less viable as a food product.

Nutrient Levels

One strong indication of the health of your kelp is its color. Nutrient-rich kelp is dark brown in color, ranging from amber to chocolate in color. Nutrient-starved kelp tends to be very light in kelp – almost translucent and yellow.

If your kelp has a dark color to it, then your site likely has enough nutrients to support the growth on your farm. If your kelp is paler in color, it may be worth checking the nutrient profile of the waters at your farm site. You can do this by purchasing a kit to measure the nitrate in the water, or by sending in a water sample to a lab. If the water on your farm site scores below 5uM of Nitrate, there may be a concern that your site is too nutrient-limited to support significant growth. Bear in mind that the nutrient profiles of different sites can change from year to year.