Petiole N03-N concentration
Crop	Growth Stage	Dry Tissue	Fresh Sap
Broccoli	Mid growth	10,000 - 20,000	1,000 - 1,600
	Button formation	8,000 - 15,000	800 - 1,200
	Preharvest	5,000 - 8,000	600 - 1,000
Cabbage	Cupping	*	1,200 - 1,500
	Early heading	*	1,000 - 1,200
	Mid heading	*	700 - 900
Cantaloupe	Early flower	12,000 - 15,000	1,000 - 1,200
	Fruit bulking	8,000 - 10,000	800 - 1,000
	First harvest	4,000 - 6,000	700 - 800
Cauliflower	Mid growth	*	1,000 - 1,600
	Curd development	*	700 - 1,000
	Preharvest	*	500 - 800
Celery	Mid Growth	7,000 - 10,000	600 - 800
	Preharvest	6,000 - 8,000	400 - 600
Lettuce	Early head formation	7,000 - 10,000	400 - 600
	Preharvest	6,000 - 10,000	300 - 500
Onion**	Bulbs 0.5-1.5 inches	*	350 - 500
Pepper	Vegetative growth	7,000 - 10,000	900 - 1,200
	Early flower/fruit	5,000 - 8,000	700 - 1,000
	Fruit bulking	5,000 - 8,000	700 - 1,000
	Preharvest	5,000 - 7,000	700 - 900
Potato	Early vegetative	17,000 - 22,000	1,300 - 1,600
(Russet Burbank)	Mid tuber/bulking	11,000 - 15,000	900 - 1,200
	Late tuber/maturation	6,000 - 8,000	550 - 700
Sweet Corn	Entire season	*	600 - 700
Tomato	Vegetative growth	10,000 - 14,000	700 - 900
	Early flower/fruit	9,000 - 12,000	600 - 800
	Fruit bulking	6,000 - 8,000	500 - 700
	Preharvest	4,000 - 6,000	400 - 600
Watermelon	Early flowering	12,000 - 15,000	900 - 1,100
	Fruit bulking	8,000 - 15,000	700 - 900
	Fruit harvest	5,000 - 8,000	500 - 700
*Not available **Long-day type of onions

PETIOLE N03-N & K SUFFICIENCY LEVELS (Source: University of Florida)
		NO3-N (ppm)	K (ppm)
Crop	Growth Stage	Fresh Sap	Fresh Sap
Cucumber	First blossom	800 - 1000	NR
	Fruits 3-inches long	600 - 800
	First harvest	400 - 600
Broccoli &	Six-leaf stage	800 - 1000	NR
Collards	Just prior to harvest	500 - 800
	At first harvest	300 - 500
Summer squash	First blossom	900 - 1000	NR
	First harvest	800 - 900
Muskmelon	First blossom	1000 - 1200	NR
	Fruits 2-inches long	800 - 1000
	First harvest	700 - 800
Tomato (field)	First buds	1000 - 1200	3500-4000
	First open flowers	600 - 800	3500-4000
	Fruit l-inch diameter	400 - 600	3000-3500
	Fruit 2-inch diameter	400 - 600	3000-3500
	First harvest	300 - 400	2500-3000
	Second harvest	200 - 400	2000-2500
Tomato (greenhouse)	Transplant to second fruit cluster	1000-1200	4500-5000
	Second cluster to fifth fruit cluster	800-1000	4000-5000
	Harvest season (Dec.-June)	700-900	3500-4000
Bell Pepper	First flower buds	1400 - 1600	3200-3500
	First open flowers	1400 - 1600	3000-3200
	Fruits half-growth	1200 - 1400	3000-3200
	First harvest	800 - 1000	2400-3000
	Second harvest	500 - 800	2000-2400
Eggplant	First fruit (2-inches long)	1200 - 1600	4500-5000
	First harvest	1000 - 1200	4000-4500
	Mid harvest	800 - 1000	3500-4000
Potatoes	Plants 8-inch tall	1200 - 1400	4500-5000
	First open flowers	1000 - 1400	4500-5000
	50% of flowers open	1000 - 1200	4000-4500
	100% of flowers open	900 - 1200	3500-4000
	Tops falling over	600 - 900	2500-3000
Annual Hill	October planting	-----
Strawberries	November	800 - 900	3000-3500
	December	600 - 800	3000-3500
	January	600 - 800	2500-3000
	February	300 - 500	2000-2500
	March	200 - 500	1800-2000
	April	200 - 500	1500-2000
Watermelon	Vines 6-inches long	1200 - 1500	4000-5000
	Fruit 2-inches long	1000 - 1200	4000-5000
	Fruit one-half mature	800 - 1000	3500-4000
	At first harvest	600 - 800	3000-3500
NR - No Recommended ranges have been developed.

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