As discussed in previous posts there are 12 essential plant nutrients and fertilizing with them will help to optimize growth.  For large scale agriculture there's the assumption that there are already nutrients contained in the soil and so a sample is sent off to a lab for analysis and the fertilizer is applied based upon what nutrients are deficient in the soil. For the production of high value crops it is often better to start out with "a blank canvas" having next to no nutrients and then being able to add them artificially, thereby controlling when and how much is given of a particular element.

For any of these systems there is always the potential have less than optimal levels of a particular nutrient.  Also a more likely scenario is having too much of a nutrient which is wasteful.



By using all natural substances it is assumed that there a healthy soil will produce a healthy plant and in turn those consuming the crop will also be healthier.


  • Less wasteful as it's a good way to recycle food and yard wastes through composts.
  • Will produce healthier soils which has long term benefits.  On the other hand large scale operations depend on tillage for weed control which contributes to soil erosion.


  • Some nutrients will be locked out being unavailable to the plant.  Phosphorus is by far the biggest problem here as it can take years or decades to become absorbable by the plant. 
  • Uses animal waste as a major component.  This leads to possible contamination by E. coli and other pathogens in food products.
worms in dirt



Please note that for the terminology of the following types is what it is know by locally by the author and there may be other types of names in other locations.


One Part System

This consists one component used for the whole vegetative cycle and a second used for the whole flowering cycle.


  • Simple to use, the best option for beginning growers.


  • Nutrient levels can not be customized between weeks.
  • Contain calcium together with phosphorus and sulfur.  They are not typically compatible and blending them together is a specialized process, which drives up the production cost which translates to a more expensive product for the consumer. 


ripening tomatos



Two Part System

This consists of a Grow and a Flower part together with a "Common" which is usually calcium nitrate. While not as widely used now, they were popular in the past. 


  •  Quite easy to use, and offers offers a small degree of flexibility. 


  • Not suited to high degrees of custom feeding.


Three Part System

It consists of a Grow, a Bloom, and a Micro component.  The Micro containing calcium nitrate and the micronutrients.  It is the most common type of feeding program used in the industry. 


  • Extremely customization week to week, which translates to the greatest potential for yield. 


  • More involved as the rates are always changing and thereby have a greater likelihood of user error. 



Four Part System

Consists of two parts used in conjunction in vegetative growth and two parts used in conjunction during flowering. 


  • Good compromise between simplicity and flexibility.


  • Generally more a more expensive option than using a three part.
  • Not designed for a varied feeding regiment but rather the parts are used in a one to one ratio with simplicity in mind.


For anything in life one takes out what they put in and this is certainly true when it comes to growing plants.  For someone who is inexperienced or just wants to grow casually casually a simple feeding program will suffice, but for the grower who wants to maximize yield potential a more advanced feeding program is a must.