#### TropicalRob

##### New Member

So i have been googling around for how to "properly" fertilize my crotons,

and i found this..

http://edis.ifas.ufl.edu/ep106

from University of Florida Extension - "Croton Production and Use"

The fertilization paragraph states:

**Fertilization:**Crotons grown in ground beds require less fertilizer per unit of surface area than plants grown in pots. Soil pH should be in the range of 4.5 to 6.5. Adjust soil pH with dolomite or sulfur. Fertilizers with a ratio near 3-1-2 (N-P2O5-K2O) produce excellent plants, and either liquid or slow release forms may be utilized. Pot-grown plants require 1,500-2,000 pounds (lb) nitrogen (N)/acre (A)/year (yr) [1,680-2,240 kilograms (kg) N/hectare (ha)/yr] from a 3-1-2 ratio fertilizer while 900 lb N/A/yr [1,000 kg N/ha/yr] is adequate for bed-grown plants. Excess fertilizer will reduce intensity of foliar coloration, reduce root system size and possibly lead to nutrient runoff into surface waters and/or leaching downward into ground waters.so.. Crotons like a 3:1:2 ratio NPK fertilizer.

1500-2000 Lbs of Nitrogen, for every acre, per year. I believe that range is based on light levels and temperature.

I want to know how many ounces of fertilizer i need to add to my Croton in a container.

Lets do the math..

1 Acre is 43560 square Feet.

lets use the low range of 1500 lbs of Nitrogen.

so we need 1500 Lbs of Nitrogen,

**for every 43560 square feet**, per year.

lets say our imaginary nursery was 4356 feet by 10 feet. which will match with the 43560 sq feet (ONE ACRE).

lets also assume our container pots are 8" inch SQUARE, Vertical sides, for easy math.

lets convert our nursery measurements from feet to inches, to determine how many pots we have.

4356 x 12 = 52272 inches / 8 = 6534 8" pots

10 feet x 12 = 120 inches / 8 = 15 8" pots

our nursery can hold 6534 x 15 = 98010 pots. 8" wide, back to back.

A fertilizer with a stated NPK of 3:1:2, will have

3 lbs of Nitrogen (per 100 lb bag)

1 lb of P (per 100 lb bag)

2 lbs of K (per 100 lb bag)

to get 1500 lbs of Nitrogen, we will need (1500/3) 500 bags of fertilizer. each bag 100 lbs.

or (500*100) or 50,000 lbs of fertilizer to cover our 98,010 pots

16 ounces in 1 pound. 50k x 16 is 800k.

thats 800,000 ounces of fertilizer to cover our 98,010 pots.

800,000 ounces / 98,010 pots = 8.16 ounces

**8.16 ounces of fertilizer per pot per year.**

this is using a fertilizer bag stating a NPK of 3:1:2

this is using a fertilizer bag stating a NPK of 3:1:2

looking at the florikan website for fertilizers they sell...

http://www.florikan.com/nitrogentab.html

they sell the Florikote NPK 19:6:13, and 18:6:12, both roughly the 3:1:2 ratio.

using the 19:6:13 blend.

this has 19% N, 6% P, & 13%K for every 100 lb bag of fertilizer.

so quickly..

to get 1500 lbs of Nitrogen.. we need 78 bags of fertilizer.

*we need LESS bags of fertilizer, since each 100lb bag contains*

a lot more pounds of N, P and K.

a lot more pounds of N, P and K.

78 * 100 = 7800 lbs of fertilizer.. 124,800 ounces of fertilizer.

124,800 ounces of fertilizer / 98010 pots = 1.26 ounces of fertilizer per pot.

**1.26 ounces of fertilizer per pot per year**

this is using a fertilizer bag stating a NPK of 19:6:13

this is using a fertilizer bag stating a NPK of 19:6:13

can someone verify that what I'm doing is correct?

also, if i fertilize twice a year.. do i then divide by dosage by 2?

if i fertilize 4 times a year, divide the dosage by 4?

or just do the "pour-thru" method, and if the TDS is low, add

another 1.26 ounces?

thank you in advance.

-rob