“The time has come to reclaim the stolen harvest and celebrate the growing and giving of good food as the highest gift and the most revolutionary act.”
Vandana Shiva
I have been very fortunate that the patch of soil in the Tomato Garden is so rich in nutrients that there is no need to work on improving the soil-food available to plants. However, I didn’t know this at the beginning. New to gardening, I just went and bought a bag of organic soil and one of plant food with added fertilizer, assuming that is what one does to grow healthy plants.
Until one day, a friend with much more gardening experience told me that this shouldn’t be necessary. Many leaves and branches of the oldest tree in the backyard, at some point, were heavily trimmed and left to decompose in the patch that is now “The Tomato Garden”. Hence, he said, the soil should be very rich for plants.
Plants eat mostly Hydrogen, Nitrogen, Carbon, Oxygen, Phosphorus and Potassium. Except for Carbon, plants absorb these foods through their roots after these nutrients are decomposed into ions by soil microorganisms. For example, plants eat Nitrogen, but they can’t consume this Nitrogen in its atmospheric form. To eat it, it first needs to be transformed by microorganisms, such as the bacteria Azotobacter, who transform it into ammonia (NH4+) and, in this new state, plants’ roots can then absorb it.
My inexperience feeding plants is, unfortunately, quite common amongst home gardeners. Buying food for the garden, without understanding if the plants are already able to find all the food they need in the soil, leads to the excessive fertilizer not absorbed by plants to flow to lakes, rivers and the ocean, contributing this way to Algal blooms. [2]
The Nitrogen and Phosphorus found in fertilizers, it is not only a delicious food for land plants, but also for algae and other plants in the water. When algae are overfed, they grow excessively. This growth can cause oxygen depletion in the water, killing, besides the algae, other plants and animals that also need oxygen to survive. [3]
But, as I discovered, chemical fertilizers are not necessary to nurture garden plants. For example, when planting legumes, such as peas, clovers and beans, one wouldn’t need additional Nitrogen (one of the most important nutrients for plants and generally the most limiting). On the contrary, legumes form a symbiotic relationship with rhizobia, a soil-dwelling bacteria, that creates a natural Nitrogen fertilizer for the plant, soil and neighboring plants. [4] Because of this, planting legumes is considered a cleaner alternative to using chemical fertilizers when Nitrogen is missing in the soil.
There are many other natural ways of helping plants get the food they need, like growing multiple crops at the same time, leaving crop residues as cover or adding organic matter. However, as my first experience feeding the soil suggests, before trying to nurture, one needs to understand.
There is still so much more for me to learn about plants’ nutritional needs, but, why wouldn’t a revolutionary act of growing your own good food, take some time.
Learn more about:
The importance of Legumes for Life
Fertilizers and algal blooms
Kids Gardening: Tips to nurture a healthy soil
Sources:
[1] https://en.wikipedia.org/wiki/Nitrogen_fixation#/medi/File:Nitrogen_Cycle.svg
[2] https://extension.usu.edu/waterquality/Learnaboutlakes/hab/index