Organic Soil Amendment Resources

| May 14, 2013


For the home gardener, building our soils to make them as rich and fertile as possible is generally an ongoing endeavor.

During each growing season, the plants we cultivate draw out and utilize nutrients from the soil, often leaving the earth in our beds more depleted at the end of the season than it was at the beginning.

Rebuilding our garden soils with various amendments, before, during and even after the growing season, has multiple benefits. These include:

  • helping plants grow larger and stronger

  • raising brix levels of produce

  • improving the phytonutrient density of the food we grow

  • helping plants to better withstand extremes in temperatures

  • helping plants to be more resistant to disease and pest infestation

  • helping the soil to retain moisture more effectively when it’s dry, and also drain well when the weather turns soggy

  • replenishing, enriching, and improving fertility and bioactivity of the soil with micronutrients, microorganisms and minerals


Mulching is a win-win-win proposition which has myriad benefits. These include:

  • helping to keep weeds at bay by smothering them and shutting them off from light

  • insulating the soil to help keep it from drying out so quickly in the heat of summer

  • the inevitable decomposition of mulch over time, which automatically infuses fresh organic material to the soil

Amending for Bioactivity and Fertility

Animal manures, such as those from chickens, cows, horses, sheep, goats and rabbits, etc., are among the very best amendments for improving the quality of soil, as they incorporate more beneficial microorganisms and other organic nutrients, increasing both the soil’s bioactivity as well as its fertility.

Depending on where you live, one of the great things about manure is that you can often get it very cheaply, and sometimes even for free.

Look for ads on on your local craigslist or perhaps at the bulletin board at your local farm or feed store, as folks who raise livestock are often more than happy to have others cart away their animals’ droppings for cheap or for free.

Otherwise most garden shops sell composted manure either in bulk or pre-bagged.

When adding animal matures directly into soil right before or during the growing season, it’s important to make sure that it has been well aged for at least 6 months, otherwise it can actually be too ‘hot’ and damage your plants. Fresh manure also often contains pathogenic bacteria and perhaps even parasites that are potentially harmful to humans. So it’s best to allow fresh manure to age and break down with time before using it to amend soils in which food is to be grown.

However if you’re amending soils at the end of the growing season after your harvest and won’t be planting again until the following spring or at least 6 months hence, thoroughly incorporating some fresher manure into your soil at that time shouldn’t be a problem.

Also worth considering are:

Seabird and bat guanos – rich in nitrogen, phosphorus and trace minerals.

Worm castings – full of microorganisms and bioavailable nutrients, can be added directly to soils or made into a tea for watering and/or foliar spraying.


Much of our soils have become depleted in trace minerals, and replacing those minerals is an excellent way to amend soil.

Please check out my post Soil Demineralization and Remineralization for more information on this subject.

Adding rock dusts, greensand, sea vegetables or desalinated sea minerals to your soil is a very effective way to augment its trace mineral content and also boost the yield, vigor and overall health of any plants grown in that soil.

Here are a few suggestions for resources for rock dusts and seaweeds:



Glacial rock dust

Greensand – helps loosen hard, clay soils and contains magnesium, silica and other trace minerals.

Seaweed – if you live by the sea, harvest your own!

Kelp meal – good source of chelated trace minerals.

Sea-Crop – desalinated sea minerals.

Sea-90 – sea mineral solids.



Biochar is charred, or partially burned material such as wood, that has a variety of benefits as a soil amendment. It:

  • helps to detoxify soils of residual toxic petrochemical pesticides, herbicides and synthetic fertilizers

  • improves soil drainage

  • loosens dense soil, and reducing soil compaction

  • improves soils’ moisture holding capacity

  • neutralizes and maintains pH of soil

  • provides massive microscopic surface area that is ideal for the colonization of beneficial soil microorganisms

  • provides a rich source of carbon to build hummus/organic matter and increase productivity

The better the quality, bioactivity and mineralization of the soil in which we grow our food, the better for the earth, and the and healthier that food will be for us to eat – so amend away!

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Category: Bacteria, Biochar, Brix, Compost | Manure, Conscious Land Stewardship, Earth, Fertility | Bioactivity, Food Sovereignty, Human Health, Microbiome, Nourishment, Organic Gardening, Plant Health, Raising Your Own Food, Remineralization, Sea Vegetables, Small Family Farms, Soil Ferility | Bioactivity, Soil Health, Soil Microorganisms, Soil Mineralization, Soil-Food-Web, Sustainable Agriculture, Vegetables | Fruits, Vermiculture

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