Spinach is a cool-season vegetable that grows rapidly and develops the highest quality at temperatures of 55° to 60°F and medium day lengths. The seed germinates between 32° and 60°F, and young plants withstand temperatures as low as 15° to 20°F. Seeding in the field can start as soon as the soil is tillable in the spring and can continue through early May.

Seeding for fall harvest is done mainly in August. Seeding in cool regions of northern New York for summer harvest is done in May and June. Spinach for an early spring harvest is routinely overwintered on Long Island with seeding dates around mid-September. Overwintering spinach in upstate New York is more of a gamble but can be successful if the winter is mild. Seeding for overwinter plantings in upstate New York should be done in early September.

Table 24.2.1 Recommended spacing.

Type Row1 In-row Seed depth2

(inch) (plants/foot) (Inch)

Fresh-market 12-18 6-8 0.25-0.5

Processing 12 10-15 0.25-0.5

1: For both fresh and processing markets, the most common arrangement is 4 to 5 rows on 68-72 inch beds.

2: Plant seed deeper in warm, dry soil. Seeding to desired stand is recommended rather than thinning.

24.3 Fertility

Maintain a pH of 6.5 to 6.8 in upstate New York and 6.0 to 6.2 on Long Island. Spinach is particularly sensitive to soil acidity. See Table 24.3.1 for the recommended rates of nitrogen, phosphorus, and potassium.

24.4 Harvesting

Most varieties reach harvest stage in 40 to 50 days under good growing conditions, but 50 to 70 days may be required for early spring plantings. Spinach can be harvested when it has only five or six leaves, but higher yields result when plants have ten to 12 leaves.

Spinach is usually washed before marketing. It is a very perishable product, but if picked early in the day, cooled rapidly after harvest, and topped with ice it can be stored for ten to 14 days. Optimal storage conditions are 32°F and 95 to 100 percent relative humidity.

Table 24.3.1 Recommended nutrients based on soil tests.
N pounds/acre	P2O5 pounds/acre			K2O pounds/acre			Comments
	Soil Phosphorus Level			Soil Potassium Level
	low	med.	high	low	med.	high
100-125	140	110	80	150	100	50	*Total recommended*

50-75	140	110	80	150	100	50	Broadcast and disk-in.
30-50	0	0	0	0	0	0	Apply 3-4 weeks after seeding

Table 24.3.2 Nonpathogenic disorders.
Disorder	Description
Air pollution	On the upper leaf surface this injury appears as stippling, flecking, mottling, bleaching, and marginal leaf roll. Look for white, collapsed, irregular patches.
Bolting	Spinach bolts in response to long days and high temperatures. Try slow-bolting varieties or plant earlier.

24.5 Disease Management

24.5.1 Damping-off and seed rot caused by Pythium spp.

Time for concern: At seeding and in postemergence stage

Key characteristics: Primarily a pre-emergence damping off, but if soils are very moist, then post-emergence hypocotyl rot can occur.

*Management Option*			*Recommendation*
Scouting/thresholds			No thresholds have been established.
Note(s)			Rhizoctonia may also cause damping-off of seedlings. There are no fungicides registered on spinach that are specific for this organism.
Resistant varieties			No resistant varieties are available.
Crop rotation			Rotation may help to minimize buildup of fungi.
Seed selection/treatment			Use seed treated with protective fungicide.
Site selection, Post-harvest, and Sanitation			These are currently not viable management options.
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
mefenoxam
	Ridomil Gold EC or OLF	1-2 pt		21	48	14-29	Specific for Pythium control. May be broadcast or banded over the row, then incorporated in the top 2" of soil mechanically, by rainfall, or by irrigation.

24.5.2 Downy mildew (Blue mold), Peronospora effusa

Time for concern: Season long, especially if over-wintered inoculum is present.

Key characteristics: Appears as pale yellow, irregular leaf spots on the upper surface, with corresponding grayish-purple rot on the lower leaf surface.

*Management Option*	*Recommendation*
Scouting/thresholds	No thresholds have been established.
Resistant varieties	Plant resistant varieties, see Section 24.1 Recommended Varieties.
Crop rotation	Minimum two year rotation without spinach.
Site selection	Plant in well-drained soil. Avoid planting spring spinach in the vicinity of winter spinach.
Seed selection/treatment	Infested seed should be hot-watered treated for 25 minutes at 122˚F.
Post-harvest, and Sanitation	These are currently not viable management options.

Compound(s)
Common name		Rate/A	PHI	REI	Field
	Trade name	Product	(days)	(hours)	Use EIQ	Comments
azoxystrobin
	Quadris F	12.3-15.4 fl oz	0	4	3-4	Do not apply more than 1 application of Quadris or Amistar (Group 11) before alternating with a fungicide that has a different mode of action. Make preventative applications on a 5-7 day schedule. Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees.
	Amistar 80 WDG	4-5 oz	0	4	3-4
mefenoxam
	Ridomil Gold EC or OLF	1-2 pt	21	48	14-29	PPI. May be used 21 days after planting or after the first cutting at 0.25 pt/A.
phosphorus acid
	Phostrol or OLF	2.5-5 pt	0	4		Do not exceed seven applications per season.
pyraclostrobin
	Cabrio EG	12-16 oz	0	12		No aerial application in NYS. Do not make more than 2 sequential applications before alternating to a labeled fungicide with a different mode of action (other than Group 11).

24.5.3 White rust, Albugo occidentalis

Time for concern: Season long, especially if over-wintered inoculum source is present.

Key characteristics: Chlorotic areas appear on the upper leaf surface with many shiny sori or blisters on the corresponding lower leaf surface.

*Management Option*	*Recommendation*
Scouting/thresholds	No thresholds have been established.
Resistant varieties	Plant resistant varieties. See Section 24.1 Recommended Varieties.
Crop rotation	A three-year crop rotation will reduce pathogen inoculum.
Site selection	Deep plowing will speed rotting of infecting plant debris. Do not plant spring crop near over-wintered fields. Fungus may occur as a surface contaminant of the seed.
Seed selection/treatment, Postharvest, & Sanitation	These are currently not viable management options.

Compound(s)
Common name		Rate/A	PHI	REI	Field
	Trade name	Product	(days)	(hours)	Use EIQ	Comments
azoxystrobin
	Quadris F	6.2-15.4 fl oz	0	4	1-3	Do not apply more than 1 sequential application of Quadris or Amistar (Group 11) before alternating with a fungicide that has a different mode of action. Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees.
	Amistar 80 WDG	2-5 oz	0	4	2-4
copper compounds
	Various	1.3-2 2/3 pt	0	24	19-32	Label varies with manufacturer and formulation. Phytotoxicity symptoms (small, circular, brown spots) have been observed on spinach treated with copper without an alkaline buffer.
mefenoxam
	Ridomil Gold EC 2 lb/gal	1-2 pt	21	48	14-29	White rust must be controlled in a preventative manner with the product applied to the soil at planting and then again after cutting.
mefenoxam + copper
	Ridomil Gold Copper	2.5 lb	21	48	54	Use after Ridomil Gold EC or immediately after each repeated cutting.
pyraclostrobin
	Cabrio EG	8-12 oz	0	12		No aerial application in NYS. Do not make more than 2 sequential applications before alternating to a labeled fungicide with a different mode of action (other than Group 11).

24.5.4 Cucumber mosaic virus (CMV) transmitted by aphids

Time for concern: Early and main season

Key characteristics: Plants show severe mosaic symptoms, stunting, and underdevelopment. When temperatures remain in the mid-50’s or lower, veinal browning and necrosis can occur. See Reference 1.

*Management Option*	*Recommendation*
Scouting/thresholds	No thresholds are available.
Resistant varieties	Plant resistant varieties. See Section 24.1 Recommended Varieties.
Site selection	Make earliest plantings downwind from weedy border areas, so that older plantings do not serve as reservoirs of virus for subsequently planted crops.
Seed selection/treatment, Crop rotation, and Postharvest	These are currently not viable management options.
Sanitation	Because weed hosts harboring CMV are common, weed management must be done before or soon after the crop is planted.
Compound(s)	No pesticides are available to manage CMV.

24.6 Insect Management

24.6.1 Green peach aphid, Myzus persicae

Time for concern: Spring and fall

Key characteristics: Adults vary in color. They are about 1/16 inch long. Aphids are known to transmit viruses. See www.nysaes.cornell.edu/ent/factsheets/.

*Management Option*			*Recommendation*
Scouting/thresholds			Early detection is important. Fields should be checked regularly. When scouting, examine the entire plant. The following thresholds have been established in the Midwest and may be applied here. For seedlings, apply an insecticide when the average number of aphids per plant is greater than or equal to one. For established plants, apply an insecticide if there are four or more aphids per plant. If the average number of aphids per plant is less than four, but any plants with more than 30 aphids, the field should be rescouted in three days. See Reference 2.
Natural enemies			Naturally-occurring predators, parasitoids, and pathogens help suppress infestations. Use Reference 3 or www.nysaes.cornell.edu/ent/biocontrol/ for identification of natural enemies.
Note(s)			Aphid populations decline rapidly during periods of heavy rainfall.
Resistant varieties			Plant varieties with resistance to cucumber mosaic virus. See 24.1 Recommended Varieties.
Mulches			Reflective foil mulches may slow down colonization of plants by winged aphids. Direct seeding through the foil is recommended for maximum protection.
Crop rotation, Site selection, Postharvest, and Sanitation			These are not currently viable management options.
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
acetamiprid
	Assail 30SG 0.3 lb/lb	2.0-4.0 oz		7	12	1-2
diazinon
	*Diazinon AG500 4 lb/gal	0.5-1 pt		14	24	10-21
imidacloprid
	*Admire Pro 4.6 lbs/gal	4.4-10.5 fl oz		21	12	4-10	Do not apply as a foliar spray.
	*Provado 1.6F 1.6 lb/gal	3.75 fl oz		7	12	1	Do not apply more than 18.75 fl oz per year as foliar spray. Allow 5 days between foliar applications.
pymetrozine
	Fulfill 0.5lb/lb	2.75 oz		7	12	2	Apply when aphids first appear but before populations build to damaging levels. Do not exceed 5.5 oz/A per season. Allow 7 days between applications.
*Restricted use only.

24.6.2 Spinach leafminer

Time for concern: Early in the season

Key characteristics: The spinach leafminer fly is 1/4 inch long and gray with black bristles. Long, white eggs are laid on the undersides of leaves. The larva is legless, yellowish white in color, and burrows into the leaf. Damage appears as blisters on the surface of the leaves. See Reference 2.

*Management Option*			*Recommendation*
Scouting/thresholds			Early detection is important. Fields should be checked regularly. It is necessary to apply an insecticide prior to the larvae mining into the leaves. Look for leafminer eggs on the undersides of leaves and any early sign of mining. In the Midwest, the threshold recommendations suggest treatment if 50 percent of the plants have eggs or leafminers. Thresholds for older plants depend upon the quality demanded by the buyers, and most commercial growers would be concerned if more than 5 percent of harvested leaves had leafminer injury. See Reference 2.
Natural enemies			Naturally-occurring predators, parasitoids, and pathogens help suppress infestations. Use Reference 3 or www.nysaes.cornell.edu/ent/biocontrol/ for identification of natural enemies.
Preventive schedule			A preventive schedule is suggested. Begin applications when spinach has two true leaves, and repeat every seven days.
Resistant varieties			No resistant varieties are available.
Sanitation			Remove weed hosts, including lambsquarter, nightshade, chickweed, and plantain. Deep-spring plowing will reduce overwintering leafminers. See Reference 2.
Crop rotation, Site selection, and Postharvest			These are not currently viable management options.
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
abamectin
	*Agri-Mek 0.15EC 0.15 lb/lb	8.0-16.0 fl oz		7	12	<1	Use an nonionic surfactant
cyromazine
	†*Trigard 0.75 lb/lb	2.66 oz		7	12		NOT FOR USE IN NASSAU AND SUFFOLK COUNTIES.
diazinon
	*Diazinon AG500 4 lb/gal	0.5-1 pt		14	24	10-21
spinosad
	SpinTor 2SC	6-10 fl oz		1	4	2-3	Do not apply more than 29 oz /A/crop.
	Entrust 80%	2-3 oz		1	4	2-3	Do not apply more than 9 oz /A/crop.
*Restricted use only.				† Not for use in Nassau/Suffolk Counties

24.6.3 Cabbage looper (CL), Trichoplusia ni

Time for concern: August 1 through harvest

Key characteristics: White, rounded eggs the size of a pinhead can be found on the undersides of leaves. Larvae are light green with white strips along each side of the body. They may reach 1 1/2 inches in length. See References 4 and 5 and www.nysaes.cornell.edu/ent/factsheets/.

*Management Option*			*Recommendation*
Scouting/thresholds			Record the occurrence and severity of the cabbage looper infestation. No thresholds have been established.
Natural enemies			Naturally-occurring predators, parasitoids, and pathogens help suppress infestations. Use Reference 3 or www.nysaes.cornell.edu/ent/biocontrol/ for identification of natural enemies.
Note(s)			Adverse weather conditions will reduce cabbage looper populations.
Resistant varieties			No resistant varieties are available.
Crop rotation, Site selection, Postharvest, and Sanitation			These are not currently viable management options.
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
Bacillus thuringiensis var. kurstaki
	Dipel DF	0.5-1.0 lb		0	4	2-4	Most effective under warm weather conditions.
	Javelin	0.12-1.5 lb		0	4	<1-10
bifenthrin
	*Capture 2EC 2 lb/gal	2.1-6.4 fl oz		40	12	3-9
beta-cyfluthrin
	*Baythroid XL 1 lb/gal	1.6-2.4 fl oz		0	12	5-8
methomyl
	*Lannate LV 2.4 lb/gal	1.5-3 pt		7	48	13-27	Do not apply when the minimum daily temperature is 32°F or lower or to seedlings less than 3" in diameter. Ground applications only.
spinosad
	SpinTor 2SC 2 lb/gal	3-6 fl oz		1	4	<1-2	Do not apply more than 29 oz /A/crop.
	Entrust 0.8 lb/lb	1-2 oz		1	4	<1-2	Do not apply more than 9 oz /A/crop.
zeta-cypermethrin
	*Mustang MAX 0.8 lb/gal	3.2-4.0 fl oz		1	12	<1	Mustard spinach only.
*Restricted use only.

24.7 Weed Management

Key characteristics: Weed fact sheets provide a good color reference for common weed identification. See Reference 6. See Chapter 4 for information on scouting/thresholds, site selection, cultivation, and banding of herbicides.

Compound(s)
Common name		Rate/A	PHI	REI	Field
	Trade name	Product	(days)	(hours)	Use EIQ	Comments
preplant incorporated
cycloate (grasses and several broadleaves, however not ragweed, nightshades, galinsoga, and mustard)
	Ro-Neet 6E 6 lb/gal	1.5-2 qt		12	34-45	Use the lower rate on sandy soils, in hot weather, or on dry soils. When possible, apply 7-10 days ahead of planting and incorporate. Rework the soil at planting.
preemergence
s-metolachlor (annual grasses, yellow nutsedge, hairy galinsoga, suppression of other broadleaf weeds)
	†*Dual Magnum 7.62 lb/gal	0.33-0.67 pts	40	24	6-12	See comments below
NOT FOR USE IN NASSAU AND SUFFOLK COUNTIES. Apply broadcast to the soil surface as a preemergence application (prior to crop or weed emergence). Banded applications may also be made but not if the crop is planted in trenches. NOTE: Do not incorporate. Do not exceed 0.67pt/A per season. Syngenta has created a new means of acquiring the indemnification required when using Dual Magnum on the vegetable crops registered on New York State’s multi-crop 24(c) Special Local Need (SLN) supplemental label. The required product label and indemnification can only be obtained through the “special labels” link found at www.farmassist.com and must be obtained by the ‘end-user’. If difficulties are encountered in using the website call the Syngenta Customer Resource Center at 866-796-4368.
postemergence
clethodim (annual and perennial grasses)
	*Select 2EC 2 lb/gal	6 - 8 fl. oz.	14	24	2-3	See comments below
For control of numerous annual and perennial grasses. Apply when grasses are 2-6 inches tall and actively growing. DO NOT apply more than 32 fl. oz. of Select 2EC (0.5 lb ai) per acre per season. Application on LONG ISLAND is restricted to no more than 16 fl. oz. of Select 2EC (0.25 lb ai) per acre per season. Always use a crop oil concentrate at 1% V/V in the finished spray volume.
clopyralid (ragweed, hairy galinsoga, smartweed, wild buckwheat, dandelion, hairy nightshade, Canada thistle)
	†*Stinger 3EC 3 lb/gal	0.33 pt	21	12	3	NOT FOR USE IN NASSAU AND SUFFOLK COUNTIES. Do not apply more than 1/2pt/A per season. Apply to spinach in the 2 to 5 leaf stage. Stinger may be applied with other herbicides labeled for use on spinach.
phenmedipham (annual broadleaves)
	Spin-Aid 1.3 lb/gal	3-6 pt		24	14-29	For use on overwintering spinach when spinach is in 4-6 leaf stage and weeds are at 2 leaf stage. May cause tipburn.
sethoxydim (annual grasses)
	Poast1.5 lb/gal	1-1.5 pt	15	12	5-7	Apply when grasses are actively growing and not under stress. Apply with 2 pt oil concentrate per acre.
*Restricted use only. † Not for use in Nassau/Suffolk Counties

24.8 References

1 Zitter, T. A., and R. Provvidenti. 1984. Virus diseases of leafy vegetables and celery, p. 737.00. In Vegetable Crops: Diseases of Leafy Vegetables and Celery. New York State Agricultural Experiment Station, Geneva.

2 Foster, R., and B. Flood, eds. 1995. Vegetable Insect Management: With Emphasis on the Midwest. Meister, Willoughby, Ohio.

3 Hoffmann, M. P., and A. C. Frodsham. 1993. Natural Enemies of Vegetable Insect Pests. Cornell Cooperative Extension. 64 pp.

4 Chapman, P. J., and S. E. Lienk. 1981. Flight periods of adults of cutworms, armyworms, loopers, and others. Search: Agriculture Number 14. New York State Agricultural Experiment Station, Geneva.

5 Andaloro, J. T., and A. M. Shelton. 1981. Cabbage looper, p. 751.00. In Vegetable Crops: Insects of Crucifers. New York State Agricultural Experiment Station, Geneva.

6 Pennsylvania State University. 1987. Weed identification, pp. 1-32. Pennsylvania State University Cooperative Extension, University Park

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