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Nutrients – When to Use Them With Cannabis!

So, let’s just get this out of the way – not all nutrients are made the same. This shouldn’t come as a surprise, as not all seeds are equal! Let’s get some basic housekeeping out the way.

Basics Nutrients

Most plants, including cannabis, need three macronutrients, which are: nitrogen (N), phosphorus (P), and potassium (K). If you look at a bottle of plant food you’ll see the NPK ration on the side. The higher the number for each element the more of it is in the bottle.

There are micronutrients as well which are important:

  • Calcium is important for cell wall development, can help soil salinity, and improves water penetration when used as a soil supplement.
  • Magnesium plays a key role in photosynthesis and carbohydrate metabolism, and helps with the stabilisation of cell structures.
  • Sulfur is necessary for the formation of chlorophyll and the production of proteins, amino acids, enzymes, and vitamins, and protects plants against disease.

Now that we understand some of the basics let’s get into some growing facts! Starting with the seedlings!

Cannabis Seedlings and Nutrients

In the early stages of the seedling, most of its food comes from the seed itself. During these early stages the plant will absorb most of its water via its leaves as the root system needs to develop. This is why you need to keep the little guys warm and place them in a humid environment.

During the first 3-4 weeks you won’t need to touch nutrients. The plant would have put on 3-4 true leaves by this stage and be officially entering a new stage of life – the vegetative growth phase.

Just by popping them into a jiffy pellet you should be good to go!

But the next stage does require a little help.

Vegetative Cannabis Plants

At the beginning of this stage some growers will go with the lighter dosage of 2:1:2 NPK ratio for around a week, just to nudge the little guy in the right direction. Also, this helps avoid that nutrient burn.

This being said, some growers put their “foot on the accelerator” and begin with a 4:2:3 NPK ratio.

Then, by mid-vegetation (around the six week mark) you’ll want to really get your plant developing strong and healthy foliage. This means most growers go with a 10:5:7 fertiliser. This level of nitrogen will assist the plant to produce nice big green leaves and loads of bud sites – just before your flowering stage. You want your plant to get all the food it can handle.

Then at the end of the veg stage you might need to start lowering the nitrogen levels and switch over to a formula that helps with the bloom stage. This is why the levels are brought down to a 7:7:7 ratio.

And like that it’s time for your plant to start flowering!

Flowering Cannabis Plants

Nutrients for the flowering stage switch from needing loads of nitrogen to potassium. This is done to promote the growth of big resinous flowers.

For the first two weeks of flowering most growers will be feeding their plants with a 5:7:10 ratio. Keeping potassium concentrations high is common for the last stage of the plant’s life. During the mid-flowering stage the ratio will be 6:10:15.

And during that last weeks of flowering, growers will be winding down all their nutrient needs as a transition to the pre-harvest flush (which can be done with a certain product). The ratio at this stage is 4:7:10.

Just like that, you know exactly how much nutrients are needed throughout your plant’s life.

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