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best nutrients for growing weed in soil

Your marijuana plants need the following primary nutrients, collectively known as macronutrients:

What nutrients does a cannabis plant need?

Nitrogen is also part of amino acids that act as building blocks for proteins in a plant. Without the necessary proteins, your cannabis plants will be weak and frail. Nitrogen is also a part of ATP, which allows plant cells to control the use of energy.


Indoor growers typically use liquid nutrients and mix them in with water before watering plants. Using liquid nutrients is usually more time consuming, as you typically have to measure and mix them in water 1-2 times a week.

Best nutrients for growing weed in soil

How to Adjust PH Using Synthetic Nutrients

If using filtered or RO water (which contains few micronutrients) it’s a good idea to also add a Calcium/Magnesium supplement by the same brand that makes your base nutrients. Cannabis plants go through a lot of Calcium and Magnesium!

Recommended Soil Nutrients

With many soil mixes, plants run out of nutrients and start growing slowly after a few weeks. When a plant looks lime green all over (especially if bottom leaves are turning yellow and falling off), it needs more nutrients overall. The left plant received plain water and started turning yellow after the soil ran out of nutrients. The right plant has been receiving nutrients in the water and is a nice healthy green color.

Summary of a Marijuana’s Nutrient Needs in Soil

Just about any soil potting mix contains enough nutrients for seedlings

Best nutrients for growing weed in soil

Magnesium is one of the most important secondary nutrients. It is rare to experience a magnesium deficiency when you grow weed outdoors. However, it is more common when you grow indoors or if you use a soilless medium. It is a crucial player in chlorophyll production. You must infuse your plant with magnesium immediately if you spot signs of deficiency.

If you think that nutrient options are confined to marijuana plants that grow in soil, you are wrong! There are also a variety of hydroponic options, which tend to muddy the waters for the uninitiated. But fear not! We’re here to provide an easy guide to selecting the best nutrients for growing marijuana and producing fantastic yields.

Nitrogen is one of the most common nutrients in cannabis, and growers are aware of its importance. Despite this fact, nitrogen deficiency is common. It plays a significant role in most plant functions, including amino acid production and photosynthesis. Although your plants need nitrogen throughout their life cycle, it is especially important during the vegetative stage.

Despite its importance, potassium deficiencies are common. If you use a natural fertilizer such as bat guano, please note that potassium is the least abundant nutrient of the big three. Fixing major deficiencies requires a water-soluble fertilizer high in potassium.

Zinc (Immobile)

Calcium and magnesium are often overlooked when discussing the growth of the cannabis plant. It is common to find them together in a single Cal-Mag supplement, which generally contains iron as well. These nutrients are essential to the process of photosynthesis, which involves creating energy from light. Magnesium is particularly crucial for photosynthesis; it is the central atom in the chlorophyll molecule.

There are countless nutrient options when it comes to growing cannabis. Therefore, it can be difficult for inexperienced growers to find the best choice for their plants. Arguably the biggest mistake new growers make is to turn this process into an overly complicated task. Ultimately, they spend significantly more time, effort, and cash than necessary.

Please note that most nutrient deficiencies are due to excessively high or low pH levels in your water. Ideally, soil-grown marijuana plants will have a pH of 6.0-7.0. The range drops to 5.5-6.5 if you use coco coir as a growing medium or if you are growing hydroponically. When the pH is at the wrong level, it reduces the plant’s ability to absorb these nutrients.

What Elements Does a Marijuana Plant Require for a Successful Growing Cycle?

Although sulfur deficiencies are uncommon, they can occur if your fertilizer or soil doesn’t already have enough of it. Sulfur is an essential nutrient because it helps plant respiration and the synthesis and breakdown of fatty acids. If your soil or water has an excessively high pH, it could result in phosphorus loss. This is a major cause of sulfur deficiency.

The ideal ratio changes throughout the growth cycle of your marijuana plants. For instance, you need a higher proportion of N and K to P during the vegetative stage. A general rule of thumb is to remain close to a 3-1-3 (N-P-K) ratio for the first few weeks.