Cannabis Plant Nutrition by Growth Stage

Learn about the nutrition your cannabis plants need during each growth stage.
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Plant nutrients are often divided into two categories: macronutrients and micronutrients. Once you understand the roles each nutrient plays, you can learn to influence how your plant grows by supplementing during different stages of growth. Learn about your cannabis plant’s nutrition requirements by growth stage to ensure robust growth and maximum yields.

How Nutrients Support Plant Growth

Nutrients all play a different role in plant growth. No matter what you’re growing, the three main macronutrients every plant needs are potassium, phosphorus, and nitrogen. In fact, if you look at fertilizer packages for comparison, you’ll see three identifying numbers, which correlate to the N-P-K ratio:

  • Nitrogen (N) gives plants the energy needed to grow and is the primary source of plant protoplasm. It helps plants synthesize amino acids, chlorophyll, nucleic acids, proteins, and enzymes.
  • Potassium (K) supports overall plant growth, activating dozens of important enzymes for protein synthesis, sugar transport, N and C metabolism, and photosynthesis. It is especially beneficial for flower response.
  • Phosphorus (P) is especially vital for healthy roots, the basis of your seedling’s success. It is a key component of ATP (Adenosine Triphosphate), the energy unit of plants.

There are also several micronutrients that support plant growth, including but not limited to:

  • Magnesium (M) is the central core of chlorophyll molecules in your plant’s tissue. If there is a shortage of chlorophyll, there will be poor or stunted growth. Magnesium is also used to activate enzymes, complex substances that impact compounds related to a plant’s metabolism.
  • Sulfur (S) helps support growth and development, playing a role in photosynthesis, respiration, and the formation of cell membrane structures.
  • Calcium (Ca) is necessary for structural roles in the cell wall and membranes. It acts as a counter-cation, activates plant enzymes, and sends signals to plant walls to conduct growth activities.

Cannabis Plant Nutrition by Growth Stage

All nutrients are required at each stage to properly support plant growth, however, there are times in your plants’ lifecycle when some nutrients are in greater demand than others. You can support each growth stage and even increase your yield by ensuring your plant is getting the nutrition it needs.


Timing: 3-10 days after planting your seeds

What Your Plant Is Doing: During seed germination, energy for seedling growth is supplied to the plant via the cotyledons (the first above-ground parts of the newly emerging seedling). The cotyledons have dense reserves of carbohydrates and minerals to supply adequate growth for the first 10 days of growth. The only necessity for the first 10 days of seedling growth is full direct sunlight. Harvest Hero Enhanced Perlite Mix will supply sufficient amounts of potassium and phosphorus and promote strong, healthy roots, stems, and leaves. Be sure to keep the soil moist at all times during the germination phase.

What Your Plant Needs:

  • Potassium and phosphorus are the most important nutrients during this stage. They promote strong and healthy roots, stems, and leaves.
  • Oftentimes, your soil or soilless media choice provides the nitrogen your cannabis needs during the germination stage.
  • Your plant requires full sunlight during the first 10 days of growth.
  • Soil should be kept moist at all times.
  • If your seedling appears to lose its dark green color, you can use a seaweed solution to supply additional energy and minerals. Simply spray ½ seaweed solution (use ½ strength of bottle recommendations) on the young seedlings.


Timing: Weeks 2-4 after planting your seeds

What Your Plant Is Doing: During the seedling stage, your plant will grow one of the iconic characteristics of a cannabis plant: fan leaves. These first leaves often only have one ridged blade, followed by leaves with more blades. Once new leaves have five or seven blades (although some leaves may have more), your plant graduates from seedling and moves onto the vegetative stage.

What Your Plant Needs:

  • For a time, your plant can receive the nutrients it needs from the cotyledon, also known as the embryonic leaf. That means you can use minimal or no added fertilizer in the early seedling stage.
  • If you started with rooted cuttings, there’s a chance your plant will be deficient after propagation. You’ll want to use a 1-1-1 (N-K-P) fertilizer at 100 ppm (parts per million) for each scuttling to support continued root development.
  • If you do need to supplement fertilizer, a fish emulsion is a great choice. Use ¼ teaspoon of fish emulsion to 1 gallon of clear water and spray the young plants leaves until the spray drips off of the leaf surface. You can repeat this process once a week.
  • Your cannabis plant continues to require full sunlight and moist soil.


Timing: This stage averages 4 weeks but can be as short as 2 weeks and as long as 2 months depending on your growing environment

What Your Plant Is Doing: Your plant takes this time to grow bigger and stronger to support the abundance of flowers you’ll soon get to harvest.

What Your Plant Needs:

  • Your plant needs a source of plant-available silica during this time to support healthy growth down to the cellular levels. Diatomaceous earth is a top choice because it is made of almost entirely plant-available silica and helps prevent soil compaction. Harvest Hero Enhanced Perlite Mix can be used to supply this silica along with the phosphorus and potassium your cannabis needs to develop strong, healthy plant tissues.
  • Apply a nitrogen fertilizer at this stage. This nutrient gives plants the energy needed to grow, helping plants synthesize amino acids, chlorophyll, nucleic acids, proteins, and enzymes.
  • Your plant will benefit from full-strength fish emulsion and full-strength liquid seaweed during this time. You can mix the two together to save time and prevent overwatering. This can be applied once a week during this growth stage.
  • Roots are making big strides during the vegetative stage, so make sure your plant is in a big enough container. You might need to transplant at this time.

Pro tip: The longer growers run vegetative cycles, the bigger plants become. You can keep your plants in a vegetative state for an extended period of time, and in theory indefinitely, by keeping them under a light regime of 18 or more hours per day. This gives them the opportunity to continue to grow and get bigger in order to support bigger blowers. Indoor growers can manipulate the lighting and can keep plants in a vegetative state until they run out of room or if they want to take cuttings during an extended period (they want lots of cuttings).


Timing: This stages last from weeks 8-12 weeks, depending on the cultivar and environmental conditions

What Your Plant Is Doing: Your plant has made it to the final stage of growth, and you’re soon going to harvest the fruits of your labor! First, females will develop pre-flowers which are the beginnings of the resinous buds. In the middle of this stage, your plant will stop producing new buds and fatten up the current buds. By the end of this stage, trichome density increases, and your plant will get sticky.

What Your Plant Needs:

  • Calcium, magnesium, and other micronutrients are critical at the start of the flowering stage to produce strong sturdy plants with heavy buds and a robust root system. This can be accomplished by using calcium nitrate (15-0-0) at the rate of ¼ teaspoon per gallon of water. Simply spray the calcium nitrate solution weekly for the first 4 weeks of the flowering cycle.
  • Harvest Hero’s Enhance Perlite Mix continues to supply all the needed phosphorous and potassium needed. During this stage, it helps your plant develop large, fragrant buds on strong plants with high concentrations of cannabinoids and terpenes.
  • Your plant continues to benefit from a weekly spray of full-strength seaweed solution.
  • As your plant gets bigger, you might need to add trellises to support the weight.

Dig In with Harvest Hero

Our innovative Enhanced Perlite Mix mix features a unique, proprietary blend of perlite, diatomaceous earth, and essential nutrients that help support the critical vegetative growth stage of your cannabis plants. NC State conducted testing to see how cannabis plants were impacted by this 3-in-1 mix. Harvest Hero Enhanced Perlite Mix resulted in:

  • Improve Soil Conditions for an Increase in Flower Bud Dry Weight.
  • Improve Soil Conditions for an Increase in Plant Diameter.
  • Improve Soil Conditions for an Increase in Phosphorous Accumulation.
  • Improve Soil Conditions for an Increase in Potassium Accumulation.
  • Improve Soil Conditions for an Increase in CBD Yields.
  • Improve Soil Conditions for an Increase in Nitrogen Accumulation.
  • Improve Soil Conditions for an Increase in Plant Height.

Harvest Hero Enhanced Perlite Mix helps your plants get the nutrition they need to improve soil conditions, especially during critical vegetative growth weeks. It will increase the plant’s structural integrity, increase stem diameter, creating an almost impenetrable barrier. Try Harvest Hero today and grow further!

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