List of Organic Fertilizers

Organic Fertilizers

Here’s a quick list of common organic fertilizers and what they offer. Nitrogen (N),  Phosphate (P), and Potash/ Potassium (K) percentages are by weight and  “availability” is measured as immediate (fast release, available within hours),  moderate (moderate release, available within a few days), and slow (slow release,  available in weeks). We’ll include other notes about effects the fertilizer may have  on soil pH (acidity) and extra “bonus” nutrients the fertilizer is known for.  Your local gardening store may not have some of these organic fertilisers,  so try an online retailer that specializes in organic gardening.

Alfalfa Meal :

2.5% N, 1% P, 1.5% K

Slow to moderate

Best known as a “hay” for animals, meal is just ground up alfalfa that makes it  compost faster in the soil. Best tilled in as an early spring additive,  well before planting.

Bat Guano :

8% N, 6% P, 1% K

Moderate to immediate

The most common source of guano, bat guano is relatively fast in uptake and  so is often used between crop rotations (mid-summer harvest / replant) or in  late spring just before planting. Bird guano has higher nutrition numbers,  but sea bird guano is only available in a few parts of the world.

Fish Emulsion :

9% N, 0% P, 0% K

Immediate

This is a great additive when nitrogen levels are low and leafy plants need a  good boost. It is slightly acidic, so some plants may not tolerate it as well  as others.

Cotton Seed Meal :

6% N, 3% P, 1% K

Slow

A common fertilizer in areas where cotton is grown, this is a favored year-end,  pre-winter mix. Adding it to the soil before cover crops or mulch are put on  gives a rich nitrogenated soil in the spring.

Corn Gluten Meal :

0.5% N, 0.5% P, 1% K

Slow

Another common late-season, winter preparation additive, corn gluten is a  good soil stabilizer for winter.

Sea Weed :

1% N, 2% P, 5% K

Fast

Also a great source for zinc and iron, seaweed is one of the most beneficial  organic fertilizers that is freely available on the coasts. Cereal grains and  other high-potash crops can especially benefit from seaweed.

Cow Manure :

2.5% N, 1% P, 1.5% K

Moderate

Probably the most common organic fertilizer in use in the western world,  cow manure is comparable to good compost in nutrient value and uptake.  It may contain weed seeds, but is otherwise a gardener’s best friend.  Avoid manure from dairies and other industries where the cattle receive  a lot of salt.

Chicken Manure (Poultry) :

3.5% N, 1.5% P, 1.5% K

Fast

Similar to cow manure, poultry manure is often used in agriculture when organic  growing needs a quick boost. Most often, poultry manure is added after harvest  and before a second planting.

Green Sand :

1% N, 1% P, 5% K

Moderate

Literally ground up green limestone, it’s a shallow marine sediment and thus full  of the richness that the lakes and oceans can offer. The amount of nutrient depends  heavily on the source of the sand.

Compost :

2% N, 1.5% P, 1.5% K

Moderate

Compost’s actual contents are highly variable and dependent on what was used to  make them. Most good compost is a roughly even mix of the big three and can be  somewhat alkaline to the soil. Often added before planting, in-between  plantings, or at the end of the season. Rough compost can also be used as a  beneficial mulch. Also, try worm composting and making compost tea.

Soy Bean Meal :

3% N, 0.5% P, 2.5% K

Moderate

Uptake will depend heavily on conditions, but in general, soybean meal is a good  additive for longer-lasting results during soil maintenance.

Blood Meal :

12% N, 1.5% P, 0.5% K

Fast

While acidic, blood meal is a very fast “booster” for nitrogen-hungry plants or  plants suffering from deprivation. Is most often poured directly over their roots  and then covered in mulch.

Bone Meal :

4% N, 20% P, 0% K

Moderate

This is most often used in soils requiring serious amendment to bring them up to par.  Soils that routinely show high amounts of nitrogen or that produce nitrogen-burnt  plants benefit from bone meal.

Feather Meal :

12% N, 0% P, 0% K

Moderate

Another nitrogen booster, this is most often used pre-season, before planting,  to “pump up the soil” before plants go into it.

Fish Meal :

10% N, 5% P, 4% K

Fast

A fast uptake for a balanced boost of all nutrients is had with fish meal.  There’s a reason Native Americans planted a fish at the base of their corn  plants in popular legend.