You may notice some spotting on new leaves on your cannabis plants, yellowing between the veins.
These are some of the first signs to watch out for with a calcium deficiency.
One thing marijuana plants love is calcium, and if you’re not supplementing with enough of it you will run into issues pretty quick.
When lacking calcium in your plants, it can also appear to have an iron or magnesium deficiency.
If you are not sure if your plants are getting enough calcium with their nutrient feeding, there is plenty of information here to give you a definitive answer.
Let’s check out your plants,
Signs of Calcium Deficiency in Cannabis Plants
- Upper leaf issues show spotting first
- Lower leaves curl and twist
- Yellow, brown spots appear on leaf and tips
- Stunted growth
- Flower development is slow
- Brown or dark spots on leaves
- Random pattern of spots
- Stems start to become weak
- Roots have little development
- The roots begin to die in extreme cases
Why is calcium important to marijuana?
Calcium is vital for the plant’s growth.
It is an immobile nutrient so the plant cannot find the mineral in older leaves to assist in the plant’s growth.
Calcium in a marijuana plant helps build the cell walls and assists in growing root systems.
It also helps the plant against heat stress.
This secondary nutrient works alongside magnesium, which is also necessary for healthy plant growth.
Calcium deficiency affects all plants.
You may have noticed if you grow tomatoes in the summer outside without with calcium you get blossom end rot. According to Wikipedia.
Brownish spots appearing on a leaf
Causes of Calcium Deficiency
Here is a list of some of the reasons of lacking calcium
- Not using enough calcium when growing or any at all
- Growing hydroponically and not supplying enough calcium to the marijuana plant.
- Low PH soil (check your soil ph values )
- Using Reverse Osmosis (RO) water, all minerals are removed.
- This is the best water, you can use for growing. You must supplement with calcium.
You can also run into Calcium Lockout.
Calcium lockout happens when the ph is below a certain level which causes the grow medium to become acidic which stop’s the uptake of calcium by your plants.
Here are some PH values to watch for if they are below these values:
When growing in soil: PH levels of 6.0
Hydro and Soil Less Mediums: PH levels of 5.4
Early signs, yellow spots before they turn brown
How to Fix Calcium Deficiency
If you have determined you are deficient in calcium, then you should start with the following to help your marijuana plants recover quickly.
Flush plants: An essential first step to purge any leftover nutrients
Correct the PH level in water/ nutrients.
The optimal ranges should be in the following markers:
Soil, 6.0 – 6.5 pH range. Hydro or coco coir, 5.6 – 6.2 pH range
Add extra calcium nutrients a little at a time
You could try Dolomite, but a jug of cal mag would do just fine.
Some growers use tap water with great success! Just make sure you over 155 ppm. Most tap water contains calcium and magnesium in small quantities.
Calcium for Marijuana Plants:
Here are some of the popular calcium for your marijuana plants.
Safergro Biomin Calcium can be used for a rapid uptake of calcium in your plants.
It’s only a calcium supplement for your plants.
It also provides vital amino acids to the plant and can be used with soil or hydroponically and is 100 percent organic.
Late stages of calcium deficiency
Cal Mag for Cannabis:
Botanicare CAL-MAG Plus Plant Supplement is the one, two, three punch for your marijuana.
It covers all the bases.
Like Calcium for one and also magnesium and iron, so you know your plants are getting the optimal amounts of supplements they deserve.
Cal mag plus can be used in all stages of growth from vegetative to transition and flowering.
It does contain some nitrogen as well 2-0-0. So be sure to take into account when using any other nutrients.
Cal Mag Plus has 2 percent nitrogen, 3.2 percent calcium, 1.2 percent magnesium, and .1 percent iron.
This can be used in all types of growing : soil or hydroponic
Hydro Organics Earth Juice Elements Cal-n-Mag Plant Food is specifically designed to treat deficiency of calcium and magnesium with your cannabis plants.
It is also a great supplement for any time of the grow and works great in all growing conditions indoors and outdoors, in soil or hydroponic.
Cal-n-Mag contains 2 percent nitrogen and 3 percent calcium and 1 percent magnesium
Advanced Nutrients Sensi Cal-Mag Xtra Plant Nutrient is an excellent combo supplementation which provides the optimal amounts of calcium, magnesium, and iron.
On top of that amino acids specifically designed for marijuana plants.
It’s high on the nitrogen and comes in at a 4-0-0 ratio so take notice when in flower with your other blooming nutrients.
Sensi Cal-Mag is to be used with non-advanced nutrient products as they already had the required amounts of cal mag you need for your plants.
Roots Organics Elemental Supplement comes in a powder form and can easily be mixed with soil in the beginning or as a top dressing.
Made with natural organic materials like calcite lime, Dolomite Lime, gypsum and fish protein.
Providing your plants with the perfect amount of Cal-Mag and micro nutrients to promote health strong plants.
Lower leaves start to curl
Signs of Excessive Calcium
There are times when your plants cannot handle too much calcium.
It doesn’t happen too often, marijuana likes calcium and eats it like candy.
It still can happen so always manage your nutrients accordingly.
Here what to look out for:
- Leaf wilt
- Increased uptake of potassium, magnesium, manganese, iron
- Stunted growth
How to correct excess calcium
The easiest ways to resolve this issue is to simply:
Flush plants which is a great first step
Try and use some balanced nutrients.
Dial down the calcium magnesium supplementation.
Try a little at a time until you start to see improvement.
It could be as easy as a 2 ml per gallon difference.
When growing marijuana always supplement with calcium.
Look for a cal mag combo nutrient to make sure you have the proper amounts.
Getting the right amount the plants require can be tricky but you should be able to fix it before things become too severe.
Calcium deficiency with marijuana can creep up on your plants so be careful and always keep checking your plants for signs of any nutrient deficiencies.
Have you had an issue with calcium with your marijuana?
Let me know in the comments.
Grow on my friends.