Natural Fertilisers for Cannabis

Depending on the growth stage, cannabis demands more Nitrogen in the vegetative stage and more Phosphorus and Potassium in the flowering stage. 

Natural fertilizing solutions are also a great tool in feeding your plants what they need when they need it and some of the primary and secondary nutrients can be found in several sources.

Nitrogen: Bat guano, worm castings and chicken manure.
Phosphorus: Bone and fish meal, banana peel, rock dust.  
Potassium: Kelp, fish meal, and wood ash.
Magnesium: Epsom salts and dolomite, 

Calcium: Clay, gypsum, and limestone

Bat Guano

A natural fertilizer that contains all the nutrients, bat guano is most abundant in the essential macronutrient Nitrogen. 

Guano is pulled from nitrogen-rich ammonia. The eastern coasts of the Pacific and South America are home to some of the world's most considerable providers of bat guano, as is the whole of South America, Indonesia, and Madagascar. 

Commonly used by both outdoor and indoor growers, Guano sustains cannabis' basic processes such as fast green growth, the formation of healthy, vigorous roots and stems, as well as helping with flowering. 

It can be added as a crop supplement and a soil conditioner to improve soil texture. Applied on the leaves, it can also be used as a fungicide and an amazing compost activator. Guano also quickens the natural deterioration of organic compost. It naturally balances soil, cleansing it of its toxins. Guano is lauded among proficient growers also because it also improves the overall taste of the buds. 

Worm Castings

Worm castings are the leftovers of earthworms that have been digesting soil and additional organic matter. Worm castings introduce microorganisms into the ground and can also be added to compost tea which is the best way to use worm castings. Direct application of worm castings can result in weed that tastes like worm poop. 

Chicken Manure 

Rich in Nitrogen and with fair amounts of Potassium and Phosphorus this manure is made up from the bedding of chicken coups and is a commonly used fertiliser in gardening. 

Chicken manure does however need proper composting to break down some of the more potent nutrients that it contains. If it is applied in too raw a form then it can cause damage to your plants. 

Bone and Fish Meals 

If your pot plants are craving some Nitrogen, the bones and other inedible parts of fish can be ground down into a fine powder, enriched with fish emulsion or pressed fish oil, and applied to the soil. Alternatively, you can also use blood, bone, and soy meal.

Wood Ash

Wood ash will give a boost of Potassium to your cannabis plants. Ash can be lightly scattered on plants and can also be added to compost. Hardwood trees including oak and maple are known to release more nutrients in their ash than other trees. Wood ash can also be used to deter pests including slugs and snails. 

Epsom Salts

Epsom salt or magnesium sulfate is the best natural solution to boost magnesium and sulfur in your cannabis crops with little to no risk of overfeeding. Epsom salts can be purchased in a gardening store.

Dolomite Limestone

This mineral solution is perfect for when cannabis plants need a boost of calcium. Dolomite lime is also one of the best ways to treat acidic soils  

Kelp and Molasses

Kelp is found in shallow saltwater near coastal areas and acts as an ideal food resource in the brewing of liquid fertilisers like compost tea. To introduce more bacteria you can use molasses or black treacle, which is the dense byproduct of the refining of sugarcane or sugar beets into sugar.

More on this topic from Soft Secrets:

Vegan Weed, The Cleanest Green