Natural Fertilizer Notes

Below was extracted from Quick Guide: 10 Natural Fertilizers to Improve Crop Production

  • Fish emulsion:
    • Made with heat or acid treatment – N-P-K (nitrogen-phosphorus-potassium) ratio of 5-2-2.
    • created using enzymes rather than heat; so does not stink [clearly, not what we have used] – N-P-K ratio for hydrolyzed fish fertilizers is 4-2-2.
  • Bone meal — average N-P-K ratio of 3-15-0. The phosphorous in bone meal takes a few months to become available to plants via microbial processes in the soil. It also contains calcium, another essential plant nutrient.
  • NOTE – Phosphorous is most available in soil with pH between 6.0 and 7.0
  • Composts made with primarily plant residues do not generally contain troublesome amounts of salt. A typical N-P-K ratio for compost is 2-1-1.
  • Manure – Most cattle and horse manures have an average N-P-K ratio of 1-0.5-0.5 while poultry manures tend to be better high-nitrogen fertilizers (3-1-1 on average). The nutrients in manure are not immediately available to plants and can take up to several years to be released by soil microbes. In general, about half of the total nitrogen is available the first year.
  • Rock Phosphate is an excellent source of phosphorous, with an N-P-K ratio of 0-2-0. The phosphorous contained in rock phosphate becomes more available the second year after application, and phosphorous is most available within the soil when the pH ranges between 6.0 and 7.0. 
  • Cottonseed meal is a high-nitrogen fertilizer with an average N-P-K ratio of 6-0.4-1.5. It takes several months to be processed by soil microbes and broken down so that it can release the nutrients
  • Alfalfa meal – Average N-P-K ratio of 2-1-2. It takes one to four months to be broken down by the soil microbes
  • Blood meal is a very high-nitrogen fertilizer with an N-P-K ratio of 12-0-0. 
  • Feather meal is a great high-nitrogen fertilizer with an N-P-K ratio between 7-0-0 and 12-0-0. Takes four months or longer to break down and release its nutrients.
  • Liquid kelp – Amounts of nitrogen, phosphorous and potassium in liquid kelp are minimal, it is high in essential trace nutrients as well as plant growth hormones that accelerate plant growth and improve flowering


Using Wood Ash from here.

Use the alkalinity of wood ash to improve soil for brassicas such as cabbage and Brussels sprouts. This is a great way to prevent club root, a common disease when soil’s too acidic. Apply it the winter before planting, or as a side dressing around actively growing plants.

Wood ash can play a useful role in correcting overly acidic soil. Most vegetables need a pH of 6.5 to 7.0, so if your soil’s below 6.5 sprinkle wood ash over the surface then rake or fork it in. Test your soil using an inexpensive test kit if you don’t already know its pH. Wood ash is particularly useful if you use lots of cattle manure in your garden, as this type of manure is very acidic.

Wood ash is approximately half as effective as lime in neutralizing acid. As a general rule, apply about two ounces of ash to every square yard (50-70g per square meter). Do this on a still day in winter and wear gloves to protect your hands.

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