Chemistry of Gardening

Image from Moon Co's blog.
By Penelope Leggett, Better Farm Intern
Many gardeners know that fertilizer can assist in plant growth and produce production; but what is the fertilizer actually doing for your plants and landscape?

Fertilizers contain the three essential micro-nutrients for most plants: nitrogen, potassium, and phosphorus. The need for these minerals makes the use of fertilizer popular—but the production and use of inorganic fertilizer can harm the environment. To have healthier plants and maintain an eco-friendly garden, there are simple solutions to getting these essential nutrients to your plants.

Illustration from Landscape for Life.

Nitrogen makes up part of the chlorophyll molecules in plants, making it extremely important to the process of photosynthesis (the means by which a plant transforms potential energy into energy). When encouraging leafy growth over flower production it is best to add nitrogen to the soil.

You can spot a nitrogen deficiency by the exhibition of stunted growth of plants and yellowed leaves.

To add nitrogen organically:
1. Use old water from a fish tank to water plants to add nitrogen
2. Use manure
3. Compost old coffee grounds and use on plants (Use with discretion as coffee grounds can be acidic)
4. Many plants, such as alfalfa and soy beans, are nitrogen-fixing. So by planting these nitrogen-fixing plants in low-nitrogen soils, levels of nitrogen can be replenished.

Potassium deficiency graphic from Pigeonpea.
Potassium assists in many basic plant cell functions, making it necessary for any healthy plant. If the edges of leaves are brown and/or wilted, chances are good you've got a potassium deficiency.

To add potassium organically:
1. Coffee ground fertilizer
2. Using old banana peels in fertilizer

Phosphorous deficiency on leaves. Photo from the University of Montana.
Phosphorus helps support a healthy root system in plants and encourages flower/fruit development. Phosphorus is also relatively difficult for plants to absorb, so it is hard to add too much to soil. If flowers or fruit production is desired, adding phosphorus to the your garden can help.

Phosphorus deficiency appears through a lack of buds, purple leaves or veins, and premature falling of flowers and fruit.

To add phosphorus organically:
1. Use decomposing wood or ash from fireplace.
2. Limestone also has a high-amount of phosphorus that could be added to soil.

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