Plants grown is a standard hydroponic system go through a period of vegetative growth that lasts 4 weeks, followed by a period of flowering growth that lasts 8 – 10 weeks. Total grow time from clone to harvest is approximately 12 – 14 weeks.
There are 14 essential minerals in fertilizers that plants require for life. Macro nutrients are used by plants in the highest amounts. Micro nutrients are used in smaller amounts but are still required for life.

Water by itself is not enough to feed your plants. Water contains some native minerals but not enough, or all the required minerals. Fertilizer supplements containing all 14 essential minerals must be added to your water to create a feeding solution.
Hydroponic plants require a very precise application of fertilizer. Dosages vary from week to week, supplying plants ideal nutrition for their stage of growth, while avoiding excesses that cause toxifying salt buildups in the grow media.
In the Dr. Seeds system, all the required minerals except for calcium and magnesium are delivered in the 4 fertilizer products labelled Weeks 1 & 4, Weeks 2 & 3, Weeks 5 – 10, and Weeks 11 & 12, in precise proportions that meet the exact requirements for each stage of plant growth. For example, the Weeks 1 & 4 fertilizer delivers more phosphorus during the 1st week of growth when plants can use it to support root strike, and during the 4th week of growth when plants use it to initiate budding. Each product in the Dr. Seeds system delivers the exact nutrients plants need for the weeks they are indicated.
Calcium and Magnesium is a separate product from all the other minerals for reasons explained here.