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How to maintain healthy nutrient levels in a feeding solution.

When nutrients are added to water the resulting mixture is called a feeding solution.

There are maximum limits for how many minerals should be in a feeding solution for each stage of plant growth. When nutrients are present at healthy levels, plants are able to uptake and use them effectively. When there’s an excess of minerals, a build up accumulates in the growing media which can cause several serious problems:

  • Mineral buildup can cause plants to stop taking up water.
  • Minerals trapped in the growing media bind with minerals in the feeding solution, blocking plants from absorbing the bound minerals. This leads to a nutrient deficiency of the minerals that are bound.
  • Mineral buildup in the grow media causes pH to swing in the roots zone. Irregular pH causes minerals to precipitate out of solution and prevents plants from absorbing minerals.

Mineral buildups occur when plants are fed more minerals than they can absorb and they should be avoided. 

The total amount of minerals that should be in a feeding solution depends on plant’s stage of growth. Young seedlings and clones use fewer minerals. As plants get older and larger they use more minerals, until they reach late bloom when they start to consume less.

The list below details the total approximate recommended mineral concentration after all nutrients and additives have been added to water for all the growth stages of cannabis. Maintaining a feeding solution within these ranges helps prevent over fertilization problems.

Clone & Seedling:
350 – 500 TDS
0.7 – 1 EC

Early Vegetative:
600 – 700 TDS
1.2 – 1.4 EC

Late Vegetative:
700 – 800 TDS
1.4 – 1.6 EC

Early Flowering:
900 – 1100 TDS
1.8 – 2.2 EC

Middle Flowering:
1000 – 1200 TDS
2 – 2.4 EC

Late Flowering:
900 – 1100 TDS
1.8 – 2.2 EC