Your marijuana plants need the following primary nutrients, collectively known as macronutrients:
Liquid nutrients are typically used for indoor growing, but can be used outdoors too. Liquid nutrients are used for weed plants in soil, hydroponics, and other grow media, and can be pushed through drip lines, misters, and hoses for easy and efficient delivery.
Nitrogen is mainly responsible for a cannabis plant’s development during the vegetative stage of its life. It’s an essential part of chlorophyll and without it, a plant can’t turn sunlight into energy and it won’t be able to grow.
What nutrients does a cannabis plant need?
Growing high-quality weed requires more nutrients, or fertilizer, than most common crops.
You can add compost tea to weed plants by:
The fertilization process can repeat itself year after year as the soil continually improves—next year, your soil will be even better than this year’s.
You’ll also need a 400-micron mesh bag to place ingredients for the tea. While you can buy pre-built tea brewers, you can also easily make your own for cheap.
Products are also generally divided into “grow” solutions, high in nitrogen needed for vegetative growth, and “bloom” solutions, high in phosphorus for flower development. You can stick to these general terms if you don’t want to get bogged down with numbers.
Without adequate phosphorus, marijuana plants will show signs of undeveloped roots and might not even flower. Early signs of phosphorus deficiency shows up as a purple hue in the veins of leaves.
Check your pH.
A healthy compost tea pulls soluble nutrients and microorganisms from compost, including bacteria, fungi, and protozoa.
However, the benefits of compost tea are debated in the agricultural world. Many gardeners report quality results when using it, while others see no more benefit than applying straight compost. The uncertainty lies in whether or not growing and developing populations of microorganisms in the tea can actually benefit plants and prevent disease.
Using organics is also great if you want to be more in-tune with your natural environment. Organic fertilizers are readily available from renewable sources and are an earth friendly option.
When applied to soil, you’re adding to the soil food web by introducing a healthy population of microorganisms that are aerobic in nature. These organisms hold nutrients, aerate soil, aid water retention, increase nutrient absorption in the cannabis plant, help grow healthy roots, and help prevent diseases.
We recommend not using nutrients made for indoor growing for outdoor plants, as they are usually composed of synthetic mineral salts and can damage soil bacteria.
Only start a tea when you can apply it within 36 hours of brewing it. When using as a spray, apply in the evening or morning when the temperature is low and without direct sunlight. This period is also when the stomata—pores in the plant’s foliage—are open to receive nutrients.
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.
The goal of compost tea is to introduce nutrients, fungal colonies, and beneficial bacteria to either the soil or foliage of a marijuana plant to aid growth and protect it from harmful disease, promoting bigger, stronger, and more resilient plants.
These micronutrients are needed as well, but in much smaller quantities:
Once you have an understanding of the climate in your area, you’ll need to consider a few things before planting your weed.
You can plant directly into the ground, using the preexisting soil, but you’ll need to understand your soil’s composition and amend it accordingly. If you go this route, we recommend getting your soil tested, which will minimize headaches, and it’s easy and relatively inexpensive. A soil test will tell you the makeup and pH of your soil, any contaminants present, and will recommend materials and fertilizers to amend your soil.
However, plants grown in pots, buckets, or barrels will likely be smaller than those planted in the ground because their root growth is restricted to the size of the container. In a broad sense, the size of the pot will determine the size of the plant, although it’s possible to grow large plants in small containers if proper techniques are used.
While some plants thrive in their native soils, which are usually one of the compositions listed above, cannabis plants are best grown in soil that includes a combination of the three consistencies above—this mixture is known as loam.
These are just some examples of amendments commonly used in different types of soils. Heavily amended soils will have long lists that break down all organic nutrients they contain. Some companies create soils that offer a great structure with base nutrients, but allow you to fill in the gaps as you desire.
While shopping for soil, you might be overwhelmed by the options available at your local garden store. The soil type is the basic structure of your soil. From there, look at nutrients, microorganisms, and other amendments that improve the soil. Your choices will be flooded with words like:
You can make this yourself by combining worm castings, bat guano, and other components with a good soil and letting it sit for a few weeks, or it can be purchased pre-made from a local nursery or grow shop.
There are also commercially available soil blends that already contain the proper mix of these types of ingredients.
Soil and other media for outdoor cannabis growing.
Sustained temperatures above 85°F will cause your plants to stop growing, while continued temperatures below 55°F can cause damage and stunting to plants, even death.
Heavy clay soils drain slowly and don’t hold oxygen well, so they will need to be heavily amended. A few weeks before you plant, dig large holes where you’ll be placing your weed plants and mix in big amounts of compost, manure, worm castings, or other decomposed organic matter. This will provide aeration and drainage, as well as nutrients for the plants.
We recommend these organic fertilizers:
Buying the right soil for an outdoor cannabis grow.
Don’t underestimate the therapeutic value of gardening. It’s relaxing to spend some time outside, roll up your sleeves, and get your hands dirty for a while. And there’s nothing better than smoking something you grew yourself.
Silty soil is the ideal growing medium. It’s easy to work, warms quickly, holds moisture, has good drainage, and contains a lot of nutrients. The best silty soil is dark, crumbly loam—it’s fertile and probably won’t need any amending.
Some growers plant in containers on balconies or rooftops that are shielded from view, while some build heavy-gauge wire cages to keep thieves and animals at bay. Whatever you decide, think about how big you want your final plant to be—outdoor cannabis plants can grow to 10 feet tall or even more, depending on how much you let them go.
In general, 5-gallon pots are a good size for small-to-medium outdoor plants, and 10-gallon pots or larger are recommended for big plants. Regardless of size, you’ll want to protect the roots of your plants from overheating during warm weather, as pots can quickly get hot in direct sunlight. This will severely limit the growth of your plants, so be sure to shade your containers when the sun is high in the sky.
Heavy rains and high winds can cause physical damage to plants and reduce yields, and excessive moisture can lead to mold and powdery mildew, especially during the flowering stage.
If you allow a phosphorus deficiency to run amok, the effects are potentially devastating. Your plants will experience stunted growth, poor yields, and low resin production when they become mature. Make sure you use a fertilizer with a high amount of phosphorus or a bloom fertilizer.
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.
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.
Hydrogen, oxygen, and carbon are considered non-mineral essential plant elements. They are taken up by the plants in either gas or vapor form. In ideal growing conditions , fresh air and water will provide ample hydrogen, oxygen, and carbon. These are, of course, the basic building blocks of life.
Your marijuana plants only need a tiny amount of molybdenum, which means a deficiency in this micronutrient is rare. It plays a role in a pair of important enzyme systems that convert nitrate to ammonium.
Optimize your plants’ nutrient…
Your marijuana plants require zinc for sugar and protein production. This nutrient is crucial for the formation and retention of chlorophyll. It is also necessary for strong stem growth. Zinc deficiencies in marijuana are relatively common and manifest in significant structural changes in your plant.
You will see twisted leaf blades on the plant’s new growth while the leaves’ veins turn yellow. In some instances, you will see an extremely pale-looking plant. During the flowering stage, the plants’ buds become distorted and twisted. A lack of zinc can result in a brittle plant. In general, zinc deficiency is also linked to a lack of iron and manganese. As a result, we recommend purchasing a micronutrient mix of all three.
There are 17 essential mineral elements for plant growth broken up into macro and microelements or nutrients.
Maintaining higher proportions of P and K is critical when flowering. This is because the plants use larger amounts during the flowering stage than during the vegetative stage.
A mobile nutrient can move from one part of the plant to another as and when needed. If a plant has a mobile nutrient deficiency, parts of it accumulated in old leaves move to new leaves to make up for the shortfall. This is why the first sign of mobile nutrient deficiency appears in the oldest leaves at the plant’s base.
Many novice growers are unaware that there are ‘mobile’ and ‘immobile’ nutrients. There are also primary, secondary, and micronutrients. The difference between mobile and immobile nutrients depends on whether they can be translocated once the marijuana plant assimilates them.
It is best to reduce the proportion of nitrogen to phosphorus and potassium during flowering compared to the ratio used during the vegetative stage. It is essential to lower the portion of N at this point. It can reduce bud development and promote vegetative growth instead of generative (also known as flowering) growth.
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.
What Are Mobile and Immobile Nutrients?
Certain types of water don’t include large amounts of calcium; this makes them a poor choice if using a hydroponic system. You can treat a deficiency by using a calcium-rich substance such as lime.
Besides the macro elements, there are several more elements needed in much lower amounts. A deficiency in any of the following microelements will negatively impact the health of your plants :
You can correct a deficiency by purchasing fertilizer with the right NPK ratio. Quick treatments include urine and bat guano. If you spot a nitrogen deficiency, act fast because your plant’s yield will be significantly affected otherwise.
If a marijuana plant doesn’t receive enough of a nutrient, it will show signs of a deficiency. Let’s explore this issue in greater detail below.
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.
It is fairly unusual for marijuana plants to exhibit a phosphorus deficiency. One of the main reasons involves the pH of the water or growing medium going above 7.0. Your plants need phosphorus for photosynthesis . Phosphorus also helps the release of stored energy in carbohydrates.
What Elements Does a Marijuana Plant Require for a Successful Growing Cycle?
While marijuana plants don’t need a large amount of sulfur, it is still considered an essential macro element. As well as aiding enzyme formation, it helps to construct proteins. Sulfur is also pivotal in the development of chlorophyll molecules. If your plant is deficient in sulfur, calcium, magnesium, or iron, it can display symptoms like yellowing or dying leaves.
Potassium is the last of the ‘big three.’ It aids the production and movement of carbohydrates and sugars. It also aids cell division and helps with water uptake, root growth, and transpiration. In essence, no potassium means no plant growth!
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.
The macronutrients required for plant growth are:
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.
Marijuana plants use magnesium in very high amounts. If you believe your plants aren’t getting enough, use Epsom salts to deal with the issue. Make sure you distinguish between an iron and magnesium deficiency. Otherwise, you could end up over-fertilizing your plants.
Now, let’s take a look at 11 important nutrients for marijuana plants, along with symptoms of deficiency.