July 12, 2014

What are the Best and Most Popular Marijuana Fertilizers and Nutrients?

July 12, 2014
Cannabis fertilizer includes specific nutrients needed for proper growth.

Currently, in the U.S., a majority of states have implemented legislation for medical and/or recreational (adult-use) cannabis. The rules and regulations of this legislation vary significantly across state governments. In California, individual consumers can cultivate marijuana plants, while in Missouri, one has to obtain a doctor’s certification and medical card to do so. Regardless of your state’s cultivation laws, if you can legally grow, you will need to learn about fertilizer and find the right product for your individual needs. 

Organic Marijuana Nutrients

Healthy marijuana plants require fertilizer with three elements for strong roots and high flower yields: nitrogen (N), phosphorus (P), and potassium (K). This combination of elements will often be represented on packaging as the single entity, NPK. Nitrogen is important for leaf growth, potassium facilitates the development of flower, and phosphorus contributes to root and bud growth. 

However, nitrogen, phosphorus, and potassium aren’t the only nutrients found in weed fertilizer. Marijuana plant food also contains micronutrients such as calcium, magnesium, sulfur, and several others. While these nutrients for growing weed aid specific growth processes, they are not as crucial as the three core nutrients, NPK, which are the best nutrients for growing weed. 

Household Nutrients for Weed Plants

Before embarking on your quest to find the perfect cannabis fertilizer, you must first decide whether to utilize “homemade” nutrients or purchase products from a local gardening store. You can always make your own nutrient profile with your preferred mixture, but it is less complicated to buy pre-made nutrients. 

For example, a standard “homemade” plant food for weed might contain 4 parts cottonseed meal, 2 parts phosphate, 2 parts wood ash, 1 part limestone, and 1 part kelp meal, which would need to be purchased separately and mixed. However, the nutrients derived from these five substances can likely be purchased as one nutrient-mixed product at the store. For beginning cultivators, I’d recommend purchasing pre-mixed fertilizer. As you become more experienced, you experiment with different amounts of nutrients and make observations of your cannabis plants to determine your preferred mixtures. 

Best Fertilizer for Marijuana or Cannabis

Choosing the best fertilizer for weed can be daunting for both the experienced cultivator and the novice. If you don’t use enough or have the wrong ingredients, your marijuana plants won’t grow to their full potential, and if you use too much, your plants are likely to develop “nutrient burn,” indicated by yellow, burnt tips on the leaves. 

Early Growth

The stages of the marijuana plant’s life cycle determine the best fertilizer for cannabis. At the initial onset of the sprouting stage, you won’t likely need strong fertilizer; instead, you can use peat plugs or potting soil. You won’t need to add nutrients until the vegetative stage. 

Vegetative Stage

During the vegetative stage, you’ll need to add nutrient content to boost your marijuana plant growth and production. For plants in this stage, use an even mix of NPK mix of 20-20-20. This way, your plants will receive an equal amount of the core nutrients, nitrogen, phosphorus, and potassium.  

Flowering Stage

You should slightly adjust the fertilizer during flowering. Like other plants, cannabis thrives when it receives significant amounts of nitrogen, and it uses extra nitrogen throughout the vegetative stage. During the flowering stage, the need for nitrogen is reduced, but more phosphorus and potassium are required. I would suggest an NPK ratio of 10-30-10. The extra phosphorus helps with flower production, which will guarantee an optimal yield. 

Miracle Grow: Cannabis Fertilizer to Nourish Soil for Weed Plants

If you’re interested in gardening of any kind, you’ve probably heard of Miracle Grow. It’s one of the most popular fertilizer formulas available and is used frequently to support the growth of “regular plants.” While I nostalgically recall inexperienced cultivators claiming Miracle Grow is the best fertilizer for cannabis, you should avoid using it to grow marijuana plants. 

You shouldn’t use Miracle Grow for weed because it doesn’t contain the right balance of nutrients to produce optimal cannabis flower yields. Using strictly Miracle Grow also means you would be using the same formula for the entire lifespan of your marijuana plants. This could work in the early stages of your plants’ development, but their nutrient needs change as the plants progress through vegetative and flowering stages.  

Pot Fertilizer

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  • Vermiculite and Perlite: often sold together and great for absorbing water
  • Wood ashes: contains ample potassium and lime
  • Composting: enriches the soil to boost plant growth
  • CO2 Bomb: boosts plant growth as plants need CO2 to create energy
  • Bat guano: NPK ratio of 10-3-1, which is ideal for the vegetative stage
  • Fish meal: High in nitrogen

What Is the Best Fertilizer Food for Pot Plants?

In the early stages of pot plant growth, potting soil should suffice as you won’t need strong fertilizer. During the vegetative stage of growth, however, use a fertilizer with an equal mix of nitrogen, phosphorus, and potassium (NPK) which would be indicated by the notation 20-20-20. During the flowering stage, you want to apply fertilizer with less nitrogen and potassium but more phosphorus. This would be represented as 10-30-10. These core nutrient ratios will provide the best plant food for weed.   

How Often Should I Fertilize My Pot Plants?

Once your pot plants are 3-4 weeks old during the vegetative stage, use homemade fertilizer every other watering and use slightly less than indicated on the packaging if you purchased pre-mixed fertilizer. Continue this schedule until about 1 week before flowering. A day or two after you’ve switched lighting for flowering, start using fertilizer formula appropriate for this stage and follow the same schedule as the vegetative stage. Stop using fertilizer when the pot plants’ trichomes are almost done. Make careful observations of your pot plants during this process. If the leaves and branches are drooping or the leaves have yellow, burnt tips, you’ve likely added too much fertilizer and your plants are enduring “nutrient burn.” 

Additional Readings on Cultivation

The Weed Blog is a comprehensive source to find reviews of specific top strains of cannabis and online news resources regarding the legalization of marijuana. We are committed to helping you find valuable information about cannabis on our website. With marijuana law constantly changing, learn about the latest legislation from our website and what you can do to help. Otherwise, consider these other top tier articles regarding cannabis cultivation:

How to Organize the Watering Process When Growing Marijuana

What You Need to Know about Autoflowering Cannabis Seeds

What Budget Do You Need for Growing Marijuana at Home?


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