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Natural Fertilizers: Part I

Wouldn’t it be great if you could feed your lawn and landscape without ever going to the garden center? Nothing against garden centers, mind you. If I have to shop, that’s where I like to go.

My point for this post, though, is that you don’t necessarily HAVE to buy bagged products to apply to your gardens. All sorts of naturally occurring materials can be used as fertilizers. Here are just a few (as culled from my book, The Organic Lawn Care Manual):

Plant By-Products
For years, animal-based products led the way in fertilizers. People never thought twice about manure from cows, chickens, and other farm critters. Then along came fears about mad cow disease, E. coli, and other pathogens associated with animal waste. Suddenly, gardeners were taking a second look at plant-based soil amendments, some of which have wide practical application for lawns.

Alfalfa Meal
Often available in pellets containing approximately 3 percent nitrogen, alfalfa meal is readily available at farm stores as an inexpensive animal feed. It works well as a lawn soil amendment, probably because it’s a grass product.

Corn Gluten
A by-product of the milling of corn syrup products, corn gluten has been marketed as a pre-emergent weed suppressant since 1991. A thin layer of the material applied on lawns and gardens inhibits the germination of seeds (although I think it’s oversold in this regard). High in proteins, corn gluten also contains significant amounts of nitrogen, up to 10 percent. Just don’t apply it at the same time you’re trying to overseed your lawn; the seeds won’t germinate.

Cottonseed Meal
A rich source of nitrogen at 7 percent, cottonseed meal is popular as a fertilizer in some areas of the South where cotton is grown. Most organic certifiers reject cottonseed meal, however, since the majority of cotton in the United States is heavily sprayed with pesticides.

Soybean Meal
A component of many high-end natural fertilizers because of its high nitrogen content, about 7 percent, soybean meal is on the expensive side.

Seaweed Products
The anecdotal evidence has always been there. Gardeners in England and Ireland, where seaweed is plentiful, gather every speck they can find. If you’ve ever seen one of their gardens, you’d have to believe the stuff works. I’ll never forget visiting the organic gardens of Olympic gold medal marathon champion Joan Benoit Samuelson, who lives by the shore in Freeport, Maine. She harvests seaweed by the bushel and lays it in the rows between her plants, and her soil is amazing.
Much of the new generation of bagged fertilizer products has embraced seaweed as one of the key ingredients. Myriad studies have shown kelp contains all 16 elements needed for plant growth as well as a particular hormone known as cytokinin, which is responsible for cell division and cell enlargement. Cytokinin is often lacking in lawns that have suffered root declin and kelp can help restore root vigor. Many organic lawn specialists also point to increased seed germination and seedling vigor when seaweed products are applied.
Dried seaweed contains about 1 percent each of nitrogen and phosphorus and 5 percent potassium.

Wood Ash
Readily available to people who burn wood to heat their homes, wood ash is often used in place of limestone to raise the pH of soil. On average, wood ash contains about 2 percent phosphorus, 6 percent potassium, and 20 percent calcium. Beware, though: Don’t use wood ash from unknown sources, and avoid wood ash if your soil pH level is already adequate or high.

TOMORROW: Free lunches for the lawn

About The Author

Paul Tukey

An international leader of the green movement, Mr. Tukey is a journalist, author, filmmaker, TV host, activist and award-winning public speaker, who is widely recognized as North America's leading advocate for landscape sustainability and toxic pesticide reduction strategies.

Number of Entries : 1023
  • Scott Morgan

    Hi Paul,

    This post brought up an issue I’ve been wondering about lately: vegetarian organic fertilizers! I currently use Bradfield Organics 3-1-5 and am very happy with the results, but despite mostly being made from alfalfa meal it does contain some animal products. Compared to what’s available locally it’s much more towards the plant side of things than anything I’ve found, but I was curious if you had ever seen or used a good organic fertilizer that only contained plant materials. Thanks!


    • Paul Tukey

      I know the people at Bradfield and at one time they were thinking about coming out with a vegan formula. The issue is coming up with a viable, affordable source of protein. I’ll try to check in with them and get back to you.

  • Frank Kuhnert

    There are many alternatives to the vegan fertilizers which are the mined natural products. While it is true that plant minerals provide good soil nutrition, they have to go throught the breakdown to be plant available. If they have been heat processed, they have lost their bacteria. The bacteria, especially in the sea products, is very beneficial to the soils for agriculture, lawns and veggies.
    The Fertrell Company in Bainbridge, Pa can suppy a catalog with many, many natural fertilizers. They have been in business since 1946 – even longer than the chemical companies. The only meat products that they use is crab meat which is in just one fertilizer. If you want to treat your soil microbials to a feast, just give them some protein and they will smile up to you. Soil bio-activity is the secret to healthy soil.
    The corn gluten post mentions that it is a pre-emergent. Actually it allows the seed to germinate but prohibits the secondary feeder roots from becoming established so within a day of the weed germinating, the young weed dies due to no food. Works great for gardens where foxtail seeds have dropped but it also prevents veggie seeds from growing. It can be planted with sweet corn since corn gluetin is a by product of corn. For veggie seeds, use corn gluetin 10 days after planting the veggie seeds or when veggies are three inches tall.
    Across the country, have it applied as the forsythia forms its bloom buds. This bush blooms according to soil temperatures of 50-56 degrees which is the soil temperature required for early weeds to germinate.
    For immediate plant available usage, try RAW Aragonite which comes from crushed seashells. It is 39% calcium with the ocean trace minerals and bacteria. It is 60% immediate absorbable to the plants.

  • Bill

    I think the heading “Plant By-Products” might read better if it said “Animal By-Products.”

  • Tom


    Your videos on organic lawn care were part of my first introduction to this area, along with some other articles and FAQs online.

    You left out one important organic lawn amendment. Regular corn meal. It’s not nearly as high in nitrogen as corn gluten meal but it has done wonders for my lawn in controlling lawn disease.

  • Yardworkerz

    This is the general rule everytime you’ll introduce any new organic amendment to your lawn. Test it first to a small part of your lawn. If it worked, then it’s time to implement it to the entire part of your lawn. If it is unsuccessful, try another one. Keep trying, be innovative until you arrive at the perfect ‘organic material’ suited for your lawn. Any organic or natural material is safe as long as it is well prepared by time and right mixture.

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  • The Rhizome Cowboy

    Today I learned this lesson the hard way. When you go to a garden center to buy nutrients, bring the results of your soil test with you so that you can verify that the product you’re about to buy contains the ingredients that your soil needs. Bringing a copy of Paul’s book can also be helpful.

    I bought an iron supplement that also contains sulfur, but when I got home I saw that my soil test indicated excessive levels of sulfur. I wasted $40, but I at least did not put this stuff on my lawn.

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