CalMag Top Crop – Calcium and Magnesium Supplement for Soft Water & Deficiencies

CalMag by Top Crop is the nitrogen-enriched concentrated solution you need to ensure your plants never suffer from a lack of Calcium or Magnesium. If you grow with osmosis water, soft water, or simply want to prevent the dreaded deficiencies that ruin harvests, this bottle is your best ally to establish the perfect base electroconductivity (EC) and guarantee vigorous development.

Is your water ruining your grow?

You have the best lights, the best genetics, and you follow the feeding chart to the letter, but your plants still show yellowing leaves, rust spots, or slow growth. It is incredibly frustrating to put in so much effort only to feel like you are missing a piece of the puzzle, not knowing if it's a pest, a fungus, or bad luck.

The reality is that using soft water or reverse osmosis water without buffering it is a recipe for disaster. Without the necessary minerals, your plants cannot absorb the rest of the nutrients, leading to weak stems and poor production. It's not that your fertilizer doesn't work; it's that the foundation is unstable.

The solution is simple and technical: CalMag allows you to rebuild that foundation. By adding the exact dose of Calcium and Magnesium, you transform "empty" water into the perfect starting point for your plants to eat like champions.

Phase 1: Preparing the ground

Before opening the bottle, you need to know what you are working with. You cannot manage what you do not measure. This phase is about ensuring your environment and water source are ready for the mix.

• Check your water source: Determine if you are using tap water (usually has some EC) or RO/Distilled water (EC near 0.0).
• Calibrate your meter: You will need a reliable EC meter. You can find these in our section of Humidity controller and measuring instruments.
• Clean your reservoir: Ensure there are no residues from previous nutrient mixes that could alter the reading.

Phase 2: Setting up the product

CalMag is concentrated, so a little goes a long way. Preparation is key to avoiding over-fertilization.

1. Shake the bottle vigorously: Calcium tends to settle at the bottom; ensure the mixture is homogenous before dosing.
2. Prepare your tools: Have a pipette or measuring cup ready. Precision is your friend here.
3. Temperature check: Ideally, your water should be between 20-22°C to facilitate proper mixing and absorption.

Phase 3: Use / growing step by step

This is the standard protocol to ensure your nutrient solution is perfect every time you water.

1. Measure the initial EC: Dip your meter into the plain water. If it's RO water, it might read 0.0 or 0.1.
2. Add CalMag gradually: Add the product drop by drop or in small milliliters while stirring.
3. Reach the target: Your goal is to raise the EC to 0.4 mS/cm. This is the "standard water" baseline.
4. Add base nutrients: Once you are at 0.4 EC, you can now add your standard Cannabis fertilizers (Grow or Bloom) until you reach the total EC required for that week.
5. Check pH: Always adjust pH after mixing all nutrients, as CalMag and other fertilizers can alter it.
6. Observe the plants: Healthy green leaves without spots indicate the dosage is correct.

Phase 4: Closing, maintenance and learnings

Once you have finished watering, close the bottle tightly and store it in a cool, dark place to preserve its properties. Clean your pipette or measuring cup immediately to prevent salt buildup.

Take note of how much CalMag it took to reach 0.4 EC in your specific tank size. Next time, you won't need to guess; you'll just add that exact amount, speeding up your workflow significantly.

Advantages of following this flow instead of improvising

• Nutrient Unlock: Prevents nutrient lockout caused by mineral imbalances.
• Structural Integrity: Calcium strengthens cell walls, making stems thicker and stronger.
• Photosynthesis Boost: Magnesium is the central atom of chlorophyll; without it, plants cannot process light efficiently.
• Total Control: You stop guessing and start growing with scientific precision.
• Versatility: Essential for Hydroponic and Aeroponic Systems where there is no soil buffer.

Frequently Asked Questions

Can I use CalMag as a foliar spray?

Yes, if you see acute deficiencies, you can apply it foliarly for faster absorption. Use a lower dose (around 0.5ml/L) and spray when the lights are off or the sun is low to avoid burns.

Do I need this if I grow in soil with tap water?

Not always. If your tap water is "hard" (EC > 0.4), you likely have enough Calcium and Magnesium. However, if you live in a soft water area, it is still highly recommended.

Can I mix it with other brands?

Yes, CalMag by Top Crop is compatible with most nutrient lines, but always add it to the water first before other fertilizers.

How often should I use it?

Use it in every irrigation if you are using osmosis water. If using tap water, use it only when you detect deficiencies.

Personal Experience of Pevgrow’s CEO (Alan)

I remember when I switched to reverse osmosis filters thinking I was doing my plants a favor. Suddenly, everything turned pale yellow, and I couldn't figure out why since I was using expensive boosters. I learned the hard way that "pure" water is actually too empty for cannabis.

Since I started using CalMag to buffer my water up to 0.4 EC before adding anything else, the stability of my crops changed completely. It's a small step in the mixing process that makes a massive difference in the final weight and health of the buds. Now, I consider it as essential as the lights themselves.