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Calcium Deficiencies in Marijuana Plants


Why Do Cannabis Plants Need Calcium?
How to Spot a Calcium Deficiency?
How to Fix a Calcium Deficiency in Cannabis
Ways to Prevent a Calcium Deficiency
Quality Yields Are One Happy Plant Away

Are your plants losing their vigor and developing small brown spots on their leaves? You may be dealing with a calcium deficiency in cannabis.

Leaf with Calcium Deficiency

If you don’t act quickly, your plants won’t produce the high yield you expected and could even die.

Luckily, avoiding this catastrophe is easy, as long as you know what symptoms to look out for. Do you want to find out more?

Keep reading this helpful guide and learn how to spot this nutrient deficiency in your marijuana crops. You’ll also find a few tips on avoiding it altogether, so nothing comes between you and your bud.

Why Do Cannabis Plants Need Calcium?

For starters, calcium keeps plants healthy by strengthening their branches and roots. This mineral reinforces the walls of your plant’s cells in a similar way to your bones, allowing it to brave the elements.

Calcium is also incredibly important for your marijuana crop’s root growth and vitality. It’s also a key ingredient in ensuring plants are able to absorb potassium, one of the three main macronutrients.

Another reason marijuana crops need this nutrient is for them to handle the stress of warmer temperatures.

Plant lacking Calcium

How to Spot a Calcium Deficiency?

A calcium deficiency refers to a situation where your plant isn’t able to absorb this essential mineral.

There are two ways this issue can crop up while cultivating cannabis. These are:

  • The pH level of your soil or hydro setup is incorrect, and the roots can’t absorb any minerals.
  • Your choice of growing medium doesn’t have any source of nutrients.

Since marijuana plants require various minerals, you need to know what to look out for to fix the problem. Otherwise, you stand a chance of making things worse.

Here are the main symptoms of a calcium deficiency in your cannabis plants:

  • Small brown spots on marijuana leaves
  • Leaf tips start curling
  • Foliage on crops begins to die and fall off

The key to understanding this issue is that these signs first appear in new leaves rather than older ones.

You may also notice the growth of your plants become stunted, without any sign of improvement. The stems and branches feel weak and struggle to hold the weight of leaves. Another sure sign of a calcium deficiency is when your crops begin to shrivel up when exposed to very high temperatures.

Cultivators using LED lights compared to HIDs are also more likely to experience this type of nutrient deficiency. The lack of heat produced by these bulbs lowers the mobility of calcium ions, causing plants to display symptoms.

You’ll notice your buds begin to appear underdeveloped, even while using the optimal light schedule during flowering.

Finally, a calcium deficiency can lead to weak roots that may start to die or become infected with rot.

Calcium Deficiencies in Marijuana Plants

How to Fix a Calcium Deficiency in Cannabis

If you spot any of the above problems in your growing setup, don’t panic. Fixing these issues is easy, and your plants should display a visible improvement after a few days.

The first step to solving a calcium deficiency in weed is to flush your plants, regardless of what type of medium you’re using.

Pour clean water over your soil to remove any potential salts preventing your plant from absorbing calcium. If you’re using a hydroponics system, replace all the water in your tank.

After flushing your plants, you need to check the pH of your growing medium. Cannabis plants require a slightly acidic environment, so aim for a range of 6.2–6.5 for the best results.

If your plant isn’t getting enough calcium, there’s a good chance it needs magnesium too.

Hydroponic cultivators can get a Cal-Mag supplement from their nearest marijuana store. Follow the instructions on your fertilizer packaging to mix the correct ratio of nutrients to water.

Soil growers can add dolomite lime to their medium before watering their crops. The benefit of using an organic option over a synthetic version is that it slowly releases nutrients into the ground and lasts longer.

Add 6–7 teaspoons of dolomite lime for every gallon of soil. Mix the material into the top layer and water your crops with clean water. Don’t go overboard, as you can create a toxic environment and lockout nutrients altogether.

Continue feeding crops with fresh water every 2–3 days until crops start to display signs of improvement.

Once your cannabis plants look healthy again, swop over to a balanced fertilizer and continue feeding them.

Pure Indica Landrace

Ways to Prevent a Calcium Deficiency

Even after fixing a calcium deficiency in marijuana, there’s a chance your plant doesn’t develop as expected. It’s best to avoid any nutrient deficiencies in cannabis to ensure top-quality harvests.

Avoid using cheap supplements to prevent a lack of calcium in your crops. It’ll end up costing you more in the long run. Plus, you’ll reap the rewards when it comes time to harvest.

It’s also incredibly important to keep an eye on your growing medium’s pH level and water your plants correctly. That way, your plant’s roots always have access to moisture and vital minerals.

Don’t buy cannabis seeds from an unreliable source. It’s best to order them online from a trusted dispensary to ensure premium quality buds with strong, stable genetics.

Quality Yields Are One Happy Plant Away

Growing marijuana is an incredibly rewarding experience, no matter how many times you do it. Each plant provides a unique challenge from the moment you begin germinating your seeds.

Learning how to deal with a calcium deficiency in cannabis is part of the process.

When it comes to diagnosing the issue, you need to check your plant’s health thoroughly. There are a number of different nutrient deficiencies that could affect your crops, and some have similar symptoms.

Remember that a lack of calcium will first show up as brown spots on the newer leaves of your plants. Flush your medium and feed your crops dolomite lime or a synthetic supplement to fix the issue.

Keep an eye on the pH levels of your growing medium to avoid any future nutrient locks, and only buy from a reputable seed bank.

Check out some of our other growing guides to start learning how to raise amazing buds every time.

Jennifer Gallagher

Jennifer Gallagher, an experienced cannabis grower at SeedSupreme Seedbank. During a 7-year career in the marijuana growing business, Jennifer has gained a high competence in this field. As far as weed is concerned, she knows it all inside out. Jennifer is an expert in pot-growing, as well as cannabis types and their effects. She’s also familiar with all legislation nuances.