Comparisons Of House Plant Fertilizers

A variety of house plant fertilizers can be found in most supermarkets. In this study, the Phosphorus (P2O5) and the Potassium (K2O) analyses have been multiplied by 43.6% and 83% respectively to obtain the actual amounts of these two nutrients. Water-insoluble nitrogen would slowly become available over a three- to five-month period. The cost range documented is the cost of each fertilizer divided by the least expensive fertilizer. For example: for cost per ounce of 1% water-soluble nitrogen, Jobe's House Plant

Spikes cost about 72 times more than the least expensive product (Rapid Grow = 1x). The gelatin does have to be mixed up so it is comparable to the other dry fertilizers, but it costs three to five times more when total nitrogen and total actual nutrients are compared.

Following is a table of various fertilizer characteristics:

            KNOX Un- Jobe's Liquid   Plant    Rapid         
            flavored House- Sunshine Marvel   Grow   Schultz
            Gelatin  plant                                  
                     spikes                                 


            KNOX  Jobe's  L.S.   P.M.     R.G.    Schultz   

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Fertilizer|15-0-0|10-4-5|2-1-2|12-31-14|23-19-17|10-15-10|  
 Analysis |      |      |     |        |        |        |  
----------|------|------|-----|--------|--------|--------|  
Percent   |      |      |     |        |        |        |  
Water-    |  3   | 2.92 |  2  |  12    |  23    |   10   |  
Soluble N |      |      |     |        |        |        |  
----------|------|------|-----|--------|--------|--------|  
Percent   |      |      |     |        |        |        |  
Total     |      |      |     |        |        |        |  
Actual    |  15  |15.894|4.096| 37.136 | 45.394 |  24.84 |  
Nutrients |      |      |     |        |        |        |  
----------|------|------|-----|--------|--------|--------|  
Cost of   |$2.79/|$.99/ |$1.39/|$1.59/ | $1.69/ | $1.89/ |  
Product   | 8 oz.|.53 oz 16 oz.| 8 oz. |  8 oz. | 12 oz. |  
----------|------|------|------|-------|--------|--------|  
Cost/oz.  |      |      |      |       |        |        |  
of Product|$.35  |$1.88 | $.09 | $.20  |  $.21  |  $.16  |  
----------|------|------|------|-------|--------|--------|  
Cost/oz.of|      |      |      |       |        |        |  
1% Water  |$.117 |$.644 | $.045| $.017 | $.009  |  $.016 |  
Soluble N |      |      |      |       |        |        |  
          |      |      |      |       |        |        |  
Cost range| 13x  |  72x |  5x  |  2x   |   1x   |    2x  |  
----------|------|------|------|-------|--------|--------|  
Cost/oz of|      |      |      |       |        |        |  
1% Total N|$.023 |$.188 |$.045 | $.017 | $.009  | $.016  |  
          |      |      |      |       |        |        |  
Cost range|  3x  | 21x  |  5x  |  2x   |   1x   |   2x   |  
----------|------|------|------|-------|--------|--------|  
Cost/oz of|      |      |      |       |        |        |  
1% Total  |      |      |      |       |        |        |  
Actual    |$.023 |$.118 |$.022 |$.0054 | $.0046 | $.0064 |  
Nutrients |      |      |      |       |        |        |  
          |      |      |      |       |        |        |  
Cost Range|  5x  |  26x |  5x  | 1.2x  |   1x   |  1.4x  |  
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