Grotek Cal-Max, 10 L

Calcium, Magnesium, and Iron Support During High Heat, 10 L

Calcium and magnesium deficiencies tend to show up fastest under high heat or during a stretch of rapid growth, when root uptake and translocation can't always keep pace with demand — that's when tip burn in lettuce or blossom end rot in tomatoes typically appears. Grotek Cal-Max supplies calcium, magnesium, and chelated iron as a foliar spray, which is especially valuable when root-to-leaf translocation is difficult under those stress conditions.

This 10 L size is a bulk option for larger operations running extended foliar programs, applied as a spray directly to foliage during periods of heat or rapid growth.

Key Features & Benefits

• Calcium and magnesium — supports structural and metabolic plant functions
• Chelated iron included — remains plant-available even under stress conditions
• Foliar spray application — works even when root-to-leaf translocation is difficult
• Treats and prevents deficiencies — addresses issues like tip burn and blossom end rot
• 10 L size — matched to grow scale, from spot treatment to full commercial foliar programs

Who Should Use Cal-Max

Growers facing high heat or accelerated growth conditions, or seeing early signs of calcium or magnesium deficiency, will benefit from Cal-Max's targeted foliar support.

About Grotek

Grotek is manufactured by Greenstar Plant Products, a Canadian nutrient company Hydrofarm acquired in 2021; Greenstar also produces the Gaia Green fertilizer line.

Frequently Asked Questions

When is the best time to apply Cal-Max?

Apply it during high temperature conditions or periods of accelerated growth, when calcium and magnesium deficiencies are most likely to appear. Applying it before visible symptoms show up can help prevent tip burn or blossom end rot rather than just treating it after the fact.

Why use a foliar spray instead of feeding it through the roots?

Foliar application works even when root-to-leaf translocation of calcium is difficult under heat or growth stress, delivering the nutrient directly to the leaf tissue that needs it. That makes it more reliable than a root-zone application during exactly the conditions that cause deficiencies.

What deficiencies can Cal-Max help prevent?

It helps treat and prevent issues like tip burn in lettuce and blossom end rot in tomatoes, both linked to calcium availability under stress conditions. The chelated iron in the formula also supports plants showing early iron-deficiency symptoms.

Can I use Cal-Max alongside my regular nutrient program?

Yes, it's designed as a supplemental foliar treatment layered onto an existing feeding program rather than a replacement for it. Continue your base nutrient schedule and add Cal-Max specifically during high-stress conditions.