Calcium is one of the nutrients that your cannabis needs for healthy growth. It is contained in all plant cells and plays a role in important biological functions. Deficiencies or irregular amounts of calcium can cause tons of trouble for cannabis plants, so we’ll go over how to deal with each.
Cannabis plants need calcium to thrive. If there is not enough calcium or the balance is off, your plants become unhealthy and your yields suffer. We’re outlining the importance of calcium for cannabis growth and letting you know how to spot deficiencies and toxicities as well as how to treat and prevent it from happening.
So, what is calcium?
Secondary macronutrients like calcium, magnesium, and sulfur are just as essential for plants as primary macronutrients like nitrogen (N), phosphorus (P), and potassium (K). Secondary nutrients are less important than main nutrients, but they still affect plant growth. When present, they help your plants grow to their fullest potential, stay healthy, and provide you with plentiful yields.
One issue with calcium is that it stays in the cells and cannot be relocated elsewhere. For that reason, calcium is considered immobile, while nitrogen, another important nutrient, is mobile. If cannabis plants lack an immobile nutrient like calcium, problems will more often occur in new growth than in older parts of the plant. One issue cannabis growers have with calcium is that it does not leave the cell easily and therefore cannot be moved to different parts of the plant.
Why plants require calcium?
Plants must have calcium throughout all stages of growth, though the amount varies depending on the plant’s stage of life. Calcium is found abundantly embedded in cell walls, where it performs many functions. While the role of calcium in plant growth is fairly nuanced, it can be broken down into a few key contributions.
- Keeps your cannabis plant’s cells healthy. Calcium crucial for producing hormones, enzymes, and energy. Also regulates gene expression.
- Protects your plants from heat stress and calms them down in times of temperature change. Calcium is vital for plant respiration, especially when the plants are subject to drastic temperature changes.
- Stronger tissue means a stronger plant that’s more resistant to infestations and diseases.
- Calcium strengthens plant tissue. Calcium strengthens the cell wall structure in every plant part, including the stem, leaves, and roots. This increases the plant’s robustness, and it is healthier.
- The protein improves cell membrane permeability, keeping needed nutrients inside cells while allowing other nutrients to move to the outside.
- Calcium is imperative in improving marijuana plant growth, as it allows your plants to absorb other nutrients. This is why where calcium is deficient, conditions like infertility can arise as a consequence.
Calcium for different growth stages?
Seeding: If at all possible, use minimal nutrients for seedlings and cuttings. Start feeding gently at low nutrient doses (25% recommended dosage) only when your plant reaches 15 centimeters tall.
Veg: When your cannabis plants enter the vegetative phase, you will need to give them the appropriate nutrients at the recommended dosage. Your plants will need a nitrogen-rich feed with moderate levels of calcium. Fortunately, most premade cannabis nutrient mixes include secondary nutrients, including calcium, in their products.
Pre-flower: The cannabis will grow vigorously during pre-flowering, and some plants may stretch significantly in a very short amount of time. At this time, your plants will require extra calcium and magnesium; both help them grow robust roots and heavy buds.
Flower: Even though your cannabis plant will require less calcium during the flowering stage, the element is still needed for healthy bud growth. A serious calcium deficiency during flowering can negatively affect bud growth and yields, so stay on the recommended dose.
Chemical or Organic?
Choosing whether or not to grow organically (with compost and “super-soils”), or which mineral nutrients are right for your plants, will depend on your preferences and expectations when it comes to calcium.
With mineral (chemical) nutrients any decent premade cannabis nutrient will come with calcium nitrate, calcium chloride or both. Since calcium deficiencies are relatively common with nutrients of good quality, having some calcium additives on hand is prudent. This can easily boost your calcium intake. You can also try calcium nitrate, a product that contains 20% calcium and 15% nitrogen.
If you are growing organically, you have many raw materials at your disposal that contain calcium. Dolomite lime and gypsum are the usual choices, but you can also use eggshells, clamshells, oyster shells or wood ashes, and they all contain at least 30% calcium.
Calcium growing tips?
When growing in soil, aim for a pH of 6.2-7.0 pH. If your plants are being grown hydroponically, the optimal pH level for calcium intake is 6.2-6.5 pH. Below 6.2 pH, calcium will not be available to your plant, even if it is present.
Plants in coco will have a higher calcium requirement than if grown in soil. In this case, you should use special coco nutrients that contain more calcium. Alternatively, you can add calcium and magnesium additives to your feeding schedule.
The easiest way to make water-soluble calcium for your plants is to use eggshells. Crush eggshells and let them sit in vinegar for 7-10 days. Strain out the liquid, then dilution 1:1000 or 1:500 with water.
Spotting calcium deficiencies?
Despite the fact that most cannabis nutrients contain calcium, and calcium can be found in tap water, calcium deficiencies happen. Hydroponic and coco grows can be especially prone to them. Some other factors, such as powerful LED lighting, are also said to contribute to calcium insufficiency.
Although you may know the symptoms of calcium deficiency, you may still wonder what causes it. Here are a few possible causes:
- The soil has excessive amounts of potassium.
- Some tap water comes with sufficient amounts of calcium so that a deficiency is unlikely. Reverse osmosis water, however, requires a calcium/magnesium supplement.
- Growing in coco without the nutrients that keep the calcium levels up.
- A soil deficient in calcium.
- Low pH levels. If the growing medium is too acidic (below 6.2pH), calcium is unavailable to the plant, and if it exists, it is unable to extract it.
Tell tale signs of calcium deficiencies?
For one thing, calcium is an immobile nutrient, so the symptoms will seep out on new growth. One other thing, since calcium is such a critical nutrient, a deficiency can mimic other deficiencies and result in varied growing problems. Here are some of the most common symptoms:
- Root rots become more common, and plants become more susceptible to diseases like fungal and bacterial infections.
- Hollow stems and weak branches cause plants to break easily.
- It is likely that the buds won’t grow large and may appear distorted.
- Large brown spots on leaves are a telltale sign, as are edges of leaves turning brown, crumbling, then turning yellow.
- When the roots have been compromised, you will notice overall slow and stunted growth, along with weak and sickly-looking plants.
- Young growth turns yellow, twists and dies off.
- Affects new growth at the top of the plant the most.
Treating calcium deficiency?
The first step is to recognize the signs, but the second step is to treat a calcium deficiency. Here are three ways to deal with a calcium deficiency based on your growing method:
Soil: Make sure your pH is correct; it should be between 6.2 and 7.0. If the pH is off, flush the soil with pH-neutral water at the proper level. Then, add nutrients as recommended. If you want to quickly provide calcium to your plants, spray them with a calcium and magnesium solution.
Hydro / Coco: Check your EC levels. If it is below 0.3, add calcium and magnesium. In addition, check the pH level of your system. If it is outside 6.2-6.5, flush your system with pH water if it is outside the recommended levels. Alternatively, you can provide a quick emergency fix in the form of a foliar spray.