Cultural Management

Pickling Cultivars

Market acceptance. Pickling cucumber cultivars vary widely in fruit size and color as well as other characters. Because certain pickling cucumber cultivars are used for packing a specific product, processors designate the cultivars grown by buying seed and providing it to their growers for a fee.

Yield. Average yield for pickling cucumbers in North Carolina is 200 to 250 bushels per acre. Yields of 500 to 600 bushels per acre are readily obtainable with good production practices and favorable growing conditions.

Fruit quality. Grades are determined by diameter. Processors need dependable cultivars that produce a blocky rather than tapered fruit and a consistent length-to-diameter ratio. For pickling cucumbers, length requirements are met by growing cultivars with a given length-to-diameter ratio (see cultivar recommendations, Table 1). Culls include curved (crooks), and pointed (nubs) fruits (Figure 2).

Disease. Disease resistance is quite similar among recommended pickling cucumber cultivars (Table 1).

Table 1. Recommended Pickling Cucumber Cultivars for North Carolina

Cultivar	Fruit L/D a	Color b	Yield Potential c	Comments d
Atlantic	long	medium	medium	machine only, MR
Calypso	medium	medium	medium	hand, MR, N.C. standard cultivar e
Cross Country	medium-long	dark	high	hand/machine, tolerates excessive rain, MR
Discover	long	medium	high	machine, S
Excel	long	medium	medium	machine (performed well under DE growing conditions), HR
Fancipak	medium	medium	medium	hand, MR
Flurry	medium-long	medium	medium	hand/machine, MR
Jackson	medium	dark	medium	hand, very short-vined, S
Lafayette	long	medium	medium	machine, HR
Napoleon	medium-long	very dark	high	easier hand harvest, short-vined, lower seedling vigor, S
Navigator	short-medium	dark	medium	hand, high-quality fruit for processing, MR
Quest	medium	medium	medium	hand, MR
Regal	long	medium	high	machine, MR
Royal	long	medium	medium	machine, HR
Shenandoah	medium-long	medium	medium	hand/machine (similar to Cross Country), HR
Vlaspik	long	medium	medium	machine, MR
Vlasset	medium	dark	medium	hand, strong vine, MR blocky, high-quality fruit, HR
Vlasstar	medium-long	dark	high	hand/machine, MR
Wellington	medium-long	medium	medium	hand/machine, short-vined, long, small-sized fruit, HR

^a Fruit L/D ratio was measured as lenght over diameter and was determined using five 2B-size fruits. Short-medium = 2.6 to 2.8, medium = 2.8 to 3.0, medium-long = 3.0 to 3.2, long = 3.2 to 3.5.
^b Color: Dark green fruit might be more suitable than medium green fruit for fresh-market sales.
^c Yield potential: Medium indicates that consistent good yields can be expected, yet they typically are somewhat lower than high-yield-potential cultivars.
^d Indicates suitability for hand or machine harvest, shorter vines for easier harvest, and other pertinent characteristics. Anthracnose resistance: HR = high resistance, MR = moderate resistance, S = susceptible. (Contact your county Extension center for cultivar updates.)
^e Fruit length, color, and yield relative to Calypso, a standard pickling cultivar grown in North Carolina.

Slicing Cultivars

Market acceptance. Cultivars should be chosen and a seed source identified several months before planting to ensure availability of high-quality seed. Slicing cucumbers must meet the standards set by the packer, wholesaler, retailer, and consumer. Thus, growers should investigate these standards before choosing a cultivar.

Yield. Average yield for slicing cucumbers in North Carolina is 200 to 250 bushels per acre, but better yields (600 to 650 bushels per acre) can be obtained when growing a crop on plastic which is fertigated.

Certain stressful environmental conditions influence the proportion of male and female flowers produced on cucumber plants. Conditions that can influence those proportions are plant density (Lower et al. 1983; Nienhuis et al. 1984), plant damage (Cantliffe and Omran 1981), low light intensity and temperatures (Tiedjens 1928; Cantliffe 1981). Yields may be reduced due to the production of more male flowers, fewer female flowers, or both. For example, high plant populations may stress the plants for water, nutrients, or light and cause an increase in the number of male flowers. Injury caused by insect feeding or blowing soil or a combination of low-light and high-temperature conditions (this may occur in the fall) may also reduce the number of female flowers.

Ethrel and other chemicals have been used to increase female flowering and fruit set (Cantliffe and Phatak 1974; Cantliffe and Phatak 1975). However, these treatments are not always effective nor are their effects consistent due to varying environmental conditions and different stages of plant growth at time of application. Most recommended cultivars today are predominantly gynoecious and produce nearly all female flowers. Mistakes in production (e.g., overplanting, lack of timely irrigation, etc.) often cause too few female flowers or too many male flowers to be produced. If a stressful environment causes an overabundance of male flowers, the situation will usually correct itself in more favorable weather. Once excessive male flowering is discovered, it is usually too late to correct the flowering imbalance problem by spraying Ethrel. The use of Ethrel for inducing female flowering is not recommended for commercial cucumber production.

Site Selection and Preparation for Pickling and Slicing Cucumbers

Soil type. Cucumbers are adapted to a wide range of soils, but grow best on fertile, well-drained, loamy soils. Plantings on poorly drained soils can result in significant plant loss (Plate 4). Soil type should be as uniform as possible within a field so that plant establishment, crop development, and harvest are also uniform. If you are considering once-over destructive harvest of pickling cucumbers, this is especially critical because fruit development must be at the same stage to achieve profitable yields. Sandy, well-drained soils warm early in the spring, resulting in early production. They often allow mechanical operations for harvest the day after a rain. These soils require frequent irrigation and careful fertilizer management. Cucumbers grown in soils high in organic matter (e.g., Blacklands in eastern North Carolina) have the advantage of good nutrition and increased water-holding capacity; however, the soil tends to stick to fruit after harvest.

Soil and nematode samples. At least four months before planting (the fall before planting season is preferable), a soil analysis and a nematode assay should be made to determine fertilizer and fumigation needs. Root-knot nematode populations generally increase as the growing season progresses. The nematode assay is an inexpensive way of predicting yield and profit loss from nematode damage. For best results, ask your county Cooperative Extension agent for instructions on getting a proper sample and interpreting the test report. Samples can be submitted to

Agronomic Division
(Soil or Nematode Lab)
North Carolina Department of
Agriculture & Consumer Services
4300 Reedy Creek Road
Raleigh, NC 27607-6465

(Specify on the envelope whether the sample should be delivered to the Soil or the Nematode Lab.) To get accurate results, sample carefully. Test results can be used to prescribe fumigant and fertilizer needs.

Weeds. Choose fields that do not contain high populations of yield-reducing weeds such as common cocklebur, nutsedge, morningglory, or sicklepod. Previous cropping history is also important as some fields may contain residues of herbicides used in previous crops. There are several herbicides that could cause severe cucumber injury or reduce plant stands and yield due to carryover. Atrazine, Canopy, Pursuit, Scepter, Squadron, and Zorial are examples of herbicides that should not be followed by cucumbers for 12 to 24 months. A tobacco sucker control, PrimePlus, can cause injury to cucumbers, especially when high rates were used the previous year. Follow the herbicide label carefully to avoid carryover injury.

Rotation. Crop rotation is another important consideration. Cucumbers should not be planted within at least two years of a crop of cucurbits (cucumbers, squash, melons, watermelon, or gourds). Plant residue from these related crops serves as a host for plant diseases and insects that may infect or infest the next crop. Recommended rotation crops include cabbage, collards, sweetpotato, sweet corn, tobacco, wheat, rye, corn, or other grain crops.

Tillage. Plant debris should be turned and completely buried at the bottom of the furrow to facilitate decomposition. A well-tilled field will help produce a smooth, fine seed bed for uniform planting and emergence. Several weeks before planting, ridges approximately 6 to 8 inches high should be formed to insure adequate moisture for seed germination and emergence, to improve drainage after heavy rains, and to help warm the soil (Figure 3). Ridging also facilitates cultivation, which is usually necessary. Tillage should not be done when soil is heavy or wet; soil structure is impaired resulting in compaction, poorer drainage, and crusting.

Fertilization for Pickling and Slicing Cucumbers

Liming and pH. One of the most common causes of poor growth and low yield in cucumbers is unbalanced nutrition from low pH (acid) soils. Soil pH for a cucumber crop should be between 6.0 and 6.5. Liming is recommended for soils below pH 6.0. If lime is needed, incorporate it thoroughly at least two to three months before the expected seeding date. Dolimitic lime is a good lime source because it contains magnesium as well as calcium. Sufficient magnesium levels are necessary for deep green fruit color. If magnesium levels in the soil are adequate, calcitic lime can be used for raising the pH.

Minor nutrients. Cucumbers also need small quantities of micronutrients (minor nutrients) for normal plant growth and development. Manganese and zinc can be deficient in mineral soils, while copper tends to be deficient more often in soils high (5% to 10%) in organic matter. Boron is leachable and may be deficient in some North Carolina soils. Micronutrients should only be applied as indicated by soil and plant tissue testing results because high rates are often toxic. If needed, micronutrients can be broadcast before planting or applied foliarly during the growing season. Broadcast application involves spreading fertilizer over the entire field and incorporating it into the soil. Broadcast application before planting is preferred because plants take up nutrients more readily through the root system than the leaves. An adequate supply of these nutrients is then available to the seedling at planting.

Major nutrients. The major nutrients, or macronutrients, required for plant growth are nitrogen (N), phosphorus (P), potassium (K), calcium, magnesium, and sulfur. Soil test results should be used to customize a fertilizer program resulting in economic and environmentally safe use of fertilizer. In most sandy soils in North Carolina, growers should consider using supplemental sulfur. In a typical situation, 20 to 30 pounds per acre of sulfur broadcast is sufficient. Sources of sulfur are ammonium sulfate, potassium sulfate, gypsum, superphosphate, or elemental sulfur. For magnesium, magnesium sulfate could be used rather than dolimitic lime. Gypsum, lime, or calcium nitrate can be used as a supplemental calcium source.

The fertilizer program described in Table 4 will meet N, P, and K fertilizer requirements of cucumbers grown on most soils in North Carolina. The program recommends using either broadcast application before planting (option 1) or sideband application before or at planting (option 2). Some fertilizer is wasted with broadcast application because some fertilizer is placed between rows, in ditches, and on field borders. Injury, however, is less likely because fertilizer is incorporated evenly throughout the bed.

Sideband or sidedress application is more efficient than broadcast application because it involves placing fertilizer precisely near the seed or developing plant. This reduces fertilizer leaching and waste, but is less forgiving of error in application rate.

Starter fertilizer. Seedling emergence and early season growth can be improved by sidebanding a "starter" fertilizer containing phosphorus (30 to 40 pounds P₂O₅ per acre) 2 inches below and beside the seed and should be used in conjunction with option 2. Phosphorus, in particular, should be sidebanded near the seed drill because movement in the soil is limited. A starter fertilizer is especially helpful in improving plant stands and earliness under cool growing conditions.

Option 1 broadcast and a sidedress application. For most North Carolina soils, a preplant broadcast application (7 to 10 days before planting) of 80 to 100 pounds per acre each of nitrogen, phosphorus (P₂O₅), and potash (K₂O) is usually adequate (Table 4). The fertilizer should be thoroughly incorporated in the soil. Following broadcast application, one sidedress band application is suggested just before layby (about four weeks after planting, before the vines begin to grow into the row middles). For sidedressing, there is no difference in crop response to liquid or dry fertilizer materials. Do not apply more than 40 pounds of nitrogen per acre as a sidedress application because plants can be burned or killed at higher rates. At least half of the nitrogen should be in the nitrate form to reduce the chance of foliar burn and blossom end rot.

Option 2 sideband and sidedress applications. If fertilizer is to be sidebanded, reduce nitrogen and potash preplant rates at least 50% (Table 4). At these rates of nitrogen and potash, fertilizer should be placed 3 to 4 inches to the side and 2 to 3 inches below the seed to prevent salt injury. An additional sidedress application is needed at the next cultivation (10 to 14 days after planting) to meet crop need for nitrogen and potash (approximate total of 70 pounds per acre). Just before the vining stage, regardless of whether you are using option 1 or 2, recommendations call for a final sidedress application of 20 to 30 pounds of nitrogen per acre. About 20 to 30 pounds per acre of potash may be beneficial in soils low in potassium.

Table 4. Fertilizer Recommendations for Pickling and Slicing Cucumbers on Unmulched Soil

Method	Nutrient Requirements
	Application Time	N-P-K(lb/acre)a
Option 1-Initial Application Broadcast before Planting
1. Broadcast	Preplant (7-10 days)	80-100 N, P, and K
2. Sidedress	Before vines fall over and run (before layby)	20-30 N and Kb
Option 2-Sideband Application
1. Sideband	At planting	40 N and K 30-40 P (9-12 gal/acre 18-34-0 or 65-90 lb/acre 18-46-0)
2. Sidedress	10 to 14 days after planting	20-30 N and K
3. Sidedress	Before vines fall over and run (before layby)	20-30 lb N and Kb

^a N=nitrogen, P=phosphorus (P₂O₅), K=potassium (K₂O)
^b Only low in K₂O soils

Late application with full-vine coverage. Supplemental nitrogen applications later in the season may still be warranted because of heavy rainfall or a long harvesting period. Application of nitrogen, or any other fertilizer material, over the top of growing plants is extremely hazardous because fertilizer particles remaining on the leaf will burn the plant tissue. If supplemental fertilization is needed to sustain plant growth and fruit production when soil is completely covered with vines, it should be applied when the foliage is dry to reduce foliage injury. Use a conservative rate of fertilizer with a low salt index (e.g., 200 pounds per acre calcium nitrate), and irrigate immediately after application to minimize foliage burn.