Organic Fertilizers and Soil Amendments

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Weedguru Higher
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Organic Fertilizers and Soil Amendments

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Organic Fertilizers and Soil Amendments
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From the Marijuana Cultivation Bible.



N-P-K Ratios

Rabbit manure
2.4 /1.4 /0.6 Most concentrated of animal manures in fresh form.

Cow manure (dairy) 0.6 / 0.2/0.5 Often contains weed seeds, should be hot composted.

Steer manure 0.7/0.3 /0.4 Often contains weed seeds, should be hot composted if fresh.

Chicken manure 1.1/0.8 /0.5 Fast acting, breaks down quickest of all manures. Use carefully, may burn. Also, stinks like hell - composting definitely recommended.

Horse manure 0.7/ 0.3/ 0.6 Medium breakdown time.

Duck manure 0.6 / 1.4 / 0.5

Sheep manure 0.7 / 0.3 / 0.9

Worm castings 0.5 / 0.5 / 0.3 50% organic material plus 11 trace minerals. Great for seedlings, will not burn. Is a form of compost, so doesn't need composting.

Desert Bat Guano
8 /4 /1 Also contains trace elements. Fast-acting, mix in soil or as tea (1 C guano to 5 gal. water).

Cave Bat Guano 3 /10 /1

Fossilized Seabird Guano 1 /10 /1 Slow release over 3 to 12 weeks, best used as an addition to potting mix.

Peruvian Seabird Guano (pelletized) 12 / 12 / 2.5 Legendary fertilizer of the Incas. Use in soil as a long lasting fertilizer, or make into tea (1 tsp pellets to 1 gallon water).

Note: it is recommended to first compost any fresh manure before you use it for 2 reasons:

1) to lessen the chance of harmful pathogens.
2) to break down the manure to make it more usable to the plant (and reduce the smell!)

The rates for pig or human manure are not listed because of the high rate of harmful pathogens they contain.

Organic meals


Blood Meal 11 / 0 / 0 Highest N of all organic sources, very fast acting if made into tea.

Bone Meal (steamed) 1 / 11 / 0 Releases nutrients slowly.

Cottonseed Meal 6 / 2.5 / 1.5 If farming organically, check the source. May be heavily treated with pesticides.

Fish Scrap 5 / 3 / 3 Use in compost or work in soil several months before using. Usually slightly alkaline.

Fish Emulsion 4 /1 /1 Also adds 5% sulfur. Good N source for seedlings, won't burn.

Kelp Meal 1 / 0.5 / 2.5 Provides 60 trace elements, plus growth-promoting hormones and enzymes.

Soybean Meal 7 / 0.5 / 2.3 .

Coffee Grounds 2 / 0.3 / 0.2 Highly acidic, best for use in alkaline soils.


Greensand 0 / 1.5 / 7 Mined from old ocean deposits; used as soil conditioner; it holds water and is high in iron, magnesium, and silica - 32 trace minerals in all.

Eggshells 1.2 / 0.4 / 0.1 Contais calcium plus trace minerals. Dry first, then grind to powder.

Limestone (dolomitic) 0 / 0 / 0 Raises pH, 51% calcium and 40% magnesium.

Limestone (calcitic)
0 / 0 / 0 Raises pH, 65-80% calcium, 3-15% magnesium.

Crustacean Shells 4.6 / 3.52/ 0 Contain large amounts of lime. Should be ground as finely as possible for best results.

Wood Ashes 0 /1.5/ / 7 Very fast acting and highly alkaline (usually used to raise pH). Contains many micronutrients.

Crushed Granite 0 /0 /5 Contains 67% silicas and 19 trace minerals. Slow release over a long period of time.

Rock Phosphate 0 / 3 / 0 Contains 11 trace minerals. Slow release over a long period of time.

Epsom Salts 0 / 0 / 0 Provides Mg and acts as a balancer.

Soil amendments and organic material

Cornstalks 0.75 /0.4 / 0.9 Break down slowly; excellent soil conditioner. Should be shredded.

Oak Leaves 0.8 / 0.35/ 0.15 Break down slowly, shred for best results. Good soil conditioner.

Feathers 15 / 0 / 0 Chop or shred finely for best results.

Hair 14 / 0 / 0 Good soil conditioner, oils break down slowly. Chop or shred finely for best results.

Organic Fertilizers - Composition


Organic soil composition involves creating a soil medium that has a balanced amount of nutrients - NPK as well as trace elements and minerals - plus organic material that provides food for not only the plant, but also the countless soil microorganisms, fungi, worms, and bacteria that comprise a healthy soil. This soil life breaks down the raw materials of the fertilizers you add so the plants can absorb them, and also plays a part in as-yet undefined processes that aid plant growth and improve soil health.

Below are various "recipes" for both organic fertilizers and organic soil mixes.

Mix and match formulas

Pick one source from each category. The results will vary in composition from 1-2-1 to 4-6-3, but any mixture will provide a balanced supply of nutrients that will be steadily available to plants and encourage soil microorganisms.


2 parts blood meal
3 parts fish meal


3 parts bone meal
6 parts rock phosphate or colloidal phosphate


1 part kelp meal
6 parts greensand

Herbal Tea Plant Food

1 t Comfrey leaves
1 t Alfalfa leaves
1 t Nettle leaves
1 Qt boiling water

Steep for 10 min. and let cool until luke warm. Drain the leaves out and add the luke warm tea to your plants to keep them healthy and vibrant!

The reason for adding slightly warm tea (or water) to your plants is that they will be able to absorb the needed nutrients more easily by keeping the root pores open verses cold tea (or water) will have a tendency to restrict the pores, meaning a much slower process of absorption.

Comfrey is called knitbone or healing herb. It is high in calcium, potassium and phosphorus, and also rich in vitamins A and C. The nutrients present in comfrey actually assist in the healing process since it contains allantoin.

Alfalfa is one of the most powerful nitrogen - fixers of all the legumes. It is strong in iron and is a good source of phosphorus, potassium, magnesium and trace minerals.

Nettles are helpful to stimulate fermentation in compost or manure piles and this helps to break down other organic materials in your planting soil. The plant is said to contain carbonic acid and ammonia which may be the fermentation factor. Nettles are rich in iron and have as much protein as cottonseed meal.


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