Micronutrient deficiencies in cannabis – these sorts of deficiencies aren’t as important as macronutrient deficiencies, but they’re still essential for your plants to be healthy. There are many kinds of micronutrients but some of them are more common than others, and others are rarer in as far as deficiencies but you still need to know how to recognize those deficiencies.
Micronutrients in cannabis are calcium, magnesium, iron, manganese, copper, zinc and boron. Each one of these minerals is essential for your plants for many reasons; photosynthesis, transporting nutrients around the plant and for symbiotic activities – plants can’t photosynthesize without magnesium, but an excess of magnesium can block the potassium needed during the flowering period.
Your plants need all of these minerals in the perfect quantities, which can be hard to achieve but if you can recognize the deficiencies then you can easily correct the issue before it gets bad. Generally, your plants will show symptoms on the all of leaves when they’re lacking micronutrients, from the biggest to the smallest leaves, which is how you can tell that the issue is with micronutrients rather than macronutrients.
We’re going to go through a list of the different micronutrients, how to recognize deficiencies and how to fix them.
Micronutrient deficiencies in cannabis:
Calcium: This deficiency is easily spotted; it shows up through yellow spots or stains that are brown around the edges, and if you don’t stop it in time, the leaves will dry up and fall off; this will also cause vegetation or flowering to stop too, depending on which phase it’s in. This can happen due to not having enough calcium in the soil, which can easily be solved by adding some calcium into the irrigation water as a micronutrient or through a natural fertilizer like dolomite. You’ll need to catch this deficiency early as when it advances it is easily confused with potassium deficiencies, although potassium stains always appear on the edges of the leaf whereas calcium deficiencies can show up on any part of the leaf.
Magnesium: Magnesium shows up as yellow stains on your plants, similar to calcium however the brown edges don’t appear until it’s very advances. It doesn’t tend to have many negative effects and it’s hard to catch in time – the plant sucks the nutrient from the leaves very slowly, so the actual deficiency itself shows up extremely slowly too. It would be fatal for your plants to have this deficiency at the beginning of the flowering period as this is when your plant needs magnesium the most. If it shows up towards the end of the grow then you shouldn’t worry as it’s quite normal. It can be fixed by adding some magnesium to your irrigation water or adding Epson salts to the soil. If you’re using osmosis water, then you’re better off using Epson salts in the soil once they begin flowering to avoid any sort of magnesium deficiencies.
Iron: This deficiency tends to show up on the smallest leaves, and they tend to suffer from chlorosis or a discoloration of the entire leaf save the veins; they will slowly turn yellow until they fall off. It’s quite hard for your plants to develop this deficiency, but it does happen more frequently in mother plants or plants that suffer a lot of stress during the vegetation period like plants that are pruned a lot or plants in SCRoG systems which involve bending the branches. Basically, any plants that get much too stressed out can develop this deficiency. The solution is that, if you know you’re going to be stressing your plant out, make sure to give it a fertilizer rich in iron in your irrigation water before stressing the plant out to make sure that is has enough iron so that it doesn’t need to take any from the leaves.
Manganese: Manganese is present everywhere in your plants and is directly related to nitrogen absorption – a lack of this nutrient will cause your plants to stop absorbing nitrogen which can be devastating for your plants. It also affects the creation of proteins in your plants so the growth period will slow down quite a lot. The plant will begin yellowing all over, and although it might look like it’s losing all of its nutrients it’s just nitrogen. This can make for some horrible flavors in your weed if it happens towards the end of the grow. You’ll notice the plant getting yellow from the edges of the leaves towards the inside, leaving the central vein in the leaf green. You can fix this deficiency by enriching the soil with a fertilizer rich in manganese during the growth period, and a little bit at the beginning of the flowering phase.
Molybdenum: Molybdenum is the substance that fixes nitrogen to the plant, and your plants really don’t need much of it. It tends to be in boosters used at the start of the flowering period which helps stop growth and push the plant into flowering. It’s rare for plants to show deficiencies of this micronutrient, although it can appear in grows where the pH isn’t properly adjusted and the soil is too acidy. If your plants show this deficiency during the flowering period then the leaves will go yellow just like a manganese deficiency, although these leaves will rot and dry up. You can fix it by applying the micronutrient alongside a fertilizer rich in phosphorus which will help it to be absorbed. If you use it during the pre-flowering as a flowering stimulant (that contains molybdenum of course) then you’re guaranteed a successful grow without any nasty surprises.
Copper: Copper is a mineral that’s directly related to the plants’ immune system, especially when it comes to fungi. If your plants show a deficiency of this mineral then fungi like oidium and botrytis will be all over your plant as soon as they can. You can tell this is happening because your plants will look droopy even if you’ve watered them, and new sprouts on the plant will dry up and fall off. If you don’t catch this one fast enough your plant will turn to dust within days, especially if it’s very new. You can use a foliar spray rich in copper like some fungicides – this will fix the deficiency and protect your plants from fungi.
Zinc: Zinc is an indispensable mineral in your cannabis plants, as it’s needed to create chlorophyll and that obviously has repercussions for the entire plant, especially during the vegetative phase. This tends to occur in plants where the soil has a high pH level and in grows where too much flowering fertilizer has been used. If you wash the roots out too much this can also happen. The best way to solve this deficiency is to spray your plants just once with some liquid zinc solution. Make sure not to spray too much as an excess can be toxic for your plants. It’s detected generally through a complete stop in growth, the leaves get long and thin. You’ll need to take care with this mineral.
Boron: Boron is fundamentally involved in creating the plant’s cellular walls, so small deficiencies are easily distinguishable in small sprouts that haven’t grown yet. These deficiencies cause brown stains, kind of like burns or rust stains. This tends to happen in grows where too much growth fertilizer has been used, and the excess nitrogen blocks the absorption of boron. It also happens in grows where the substrate has gotten too dry, which makes boron rise to the top in the soil and the roots can’t get to it to absorb it. Plants that get a decent amount of boron and a pH between 5 and 7 should have a decent flowering period, a nice calcium absorption and the buds wil get even fatter.
Now you know what kind of micronutrient deficiencies that your plant can have, how to prevent them and what you can do to solve them if you catch them too late. Keep in mind that excesses of certain nutrients can cause deficiencies, but that’s a topic for another article.
- The Stag
What's up growmies?
Today The Stag would like to talk to you about organic nutrients for your cannabis plants while in the vegging stage. I know, I know "eye roll". This is not another article about which is a better or worse, salt or organics, but rather an article about how to make your own organic nutrients and fertilizers for your plants to get the best performance out of them.
So, let’s start , we will handle this topic in 3 stages , vegging , pre-flower, and flowering stages.
The vegetative state of a cannabis plant, also known as the "vegging" stage is when the plant (most photoperiod plants) grow their roots , branches, and leaves. This is the stage before flowering.
A plant that is busy vegging requires a bunch of nutrients , but we have 3 main categories called macro nutrients , micronutrients and non-mineral elements mostly supplied from the air and water and will be discussed in the next blog post.
Macro Nutrients
The 3 macro nutrients mostly used by cannabis plants are:
Nitrogen (N)
Phosphorus {P)
Potassium (K)
In this article we will be focusing on Nitrogen and Potassium for the vegging stage of your plants.
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.
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.
Nitrogen is also necessary to create nucleic acid, an essential ingredient in DNA or RNA, and without it, cells won't be able to grow and multiply.
Potassium has several jobs that largely help regulate the systems that keep a plant healthy and growing. It plays a large role in osmoregulation, the passive regulation of water and salt concentrations in the plant. Potassium accomplishes this by controlling the opening and closing of the stomata-the pores in the leaves-which is how a plant exchanges CO2, H20, and oxygen. Potassium also triggers the production of ATP, which works to store energy produced in photosynthesis by creating glucose.
This glucose is then used as energy for the plant as it grows.
Without sufficient potassium, you will see weak plants starved for energy that appear burnt because they are unable to successfully regulate the exchange of CO2, H20, and oxygen.
Benefits of organic fertilizers for cannabis plants :
One of the best things about organic fertilizers is they improve the soil while also improving the quality of your plants. Other benefits:
The slow release of nutrients protects plants from too many nutrients
Over time, organic fertilizers will improve the quality and diversity of life in soil
Improved airflow and water retention in soil
Renewable and sustainable
Organics stay in the soil with a lower chance of nutrient run-off
One of the most effective recipes I've used is the banana tea with some added coffee grounds for that extra Nitrogen kick.
Follow these easy steps and your plants should flourish through their vegging stage:
Fill a one-quart jar with chopped banana peels and some used coffee ground and cover them with water.
Seal the jar and leave it for about a week, occasionally checking to ensure the peels are still covered with water.
Strain the concoction, making sure to save all those banana peels for your compost pile.
Dilute the banana peel tea with water in a 1:5 ratio.
Use it to water your outdoor vegetable plants.
In our next article , we will discuss the importance of micronutrients and some new recipes for vegging, pre-flower, and flowering.
Happy growing peeps!
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- The Stag
Updated: Jun 12, 2023
Learn how to germinate seeds indoors step by step, what do you need to start, how to store your seeds and tips to get your seeds started!
Cannabis seeds: Autoflowering vs Photoperiodic
Cannabis seeds: Feminized vs regular seeds
Start your germinated seed in a small container
TIPS before starting to germinate Cannabis seeds
This is how the life of the Cannabis plant begins. A viable seed looks brown with some stripes, hard to the touch and dry. If it feels weak or it’s white or light green, it’s probably an undeveloped seed and it won’t produce a healthy plant.
You can start your seeds indoors or outdoors, but we recommend doing in indoors because there’s a bigger chance of seed survival. When germinating seeds outdoors, the small plants are exposed to cold/hot weather, wind, pests and mold. In this stage, plants are very vulnerable and it’s important to keep them safe. On the contrary, when germinating seeds indoors, we reduce or eliminate the possible negative outcomes caused by temperature changes and insects, for example.
There exist many methods for germinating seeds indoors. For example, placing your seed between cotton balls or paper towels sprayed with water, placing your seed in a jiffy or a small cup directly into the soil.
In this article, we’ll explain how to germinate with the paper towel method, as it requires simple equipment and has a high rate of germination. But first, a brief intro about Cannabis seeds, in case you haven’t chose yours yet.