Jack's Professional LX 15-5-15 Fertilizer with Cal-Mag - 25 lb, 4% Ca, 2% Mg

Jack's Professional 15-5-15 Fertilizer with Cal-Mag

This is a complete water-soluble feed built for constant liquid feed programs. Each bag carries 4% calcium and 2% magnesium alongside the 15-5-15 base. That makes it a strong fit when the source water brings little of either, such as RO or rainwater. Of the 15% total nitrogen, 12% is nitrate and 3% is ammoniacal, so about 80% of the N arrives as nitrate. Nitrate-heavy feeds tend to build compact, sturdy growth with dark green leaves rather than soft stretch. The micronutrient package covers boron, copper, iron, manganese, molybdenum and zinc. Copper, iron, manganese and zinc are EDTA chelates, which keeps them available in solution. The formula is potentially basic, rated at 69 lb of calcium carbonate equivalent per ton. In practice, root-zone pH drifts upward over time on this feed. Growers on very pure or low-alkalinity water use that drift to offset the acidity their media would otherwise build. Jack's LX system keeps nitrogen, phosphorus, potassium, calcium and magnesium together in one concentrated stock. A single stock tank and injector can run the whole program. The LX formulas are also tank-mixable with one another for custom blends. The 25 lb bag is classed as an oxidizer, so store it dry and away from fuel, sawdust and other combustibles.

Mixing Cal-Mag LX for Constant Liquid Feed

Dissolve the powder in warm water, since some raw materials go into solution more slowly than others. The label caps solubility at 4.5 lb per gallon of stock. For an injector at 1:100, 9 oz per gallon of stock delivers 100 ppm nitrogen at an EC near 0.76. Double that to 18 oz per gallon for 200 ppm N and an EC around 1.52. At 1:15, 1.35 oz per gallon of stock gives the same 100 ppm N. For hand-watering, one teaspoon per gallon of water delivers roughly 188 ppm N, and half a teaspoon about 94 ppm. Jack's suggests 50 to 125 ppm N for plugs and salt-sensitive starts. Vegetables and other heavy feeders run 200 to 300 ppm N once established. Light feeders sit lower, around 75 to 150 ppm N. Judge strength by EC rather than color, because the tracer dye spreads unevenly through the granules. Check runoff pH every week or two, since the basic formula pushes it up over a long run.

Key Features

• 15-5-15 with Calcium and Magnesium: 4% Ca and 2% Mg for RO, rain and other low-mineral water.
• 80% Nitrate Nitrogen: 12% nitrate and 3% ammoniacal N for compact, sturdy growth.
• Chelated Micronutrients: EDTA copper, iron, manganese and zinc, plus boron and molybdenum.
• One-Tank LX System: N, P, K, Ca and Mg stay together in one concentrated stock.
• Basic Reaction: Raises root-zone pH over time on pure or low-alkalinity water.

Technical Specifications