Cultural Practices and Cultivar Selections for Commercial

Vegetable GrowersBrad Bergefurd

OSU South Centers

Piketon, Ohio

Cultural Practices to Consider…

• Location• Soil types • Types of crops• Garden Layout

• Rotation of crops• Planting Methods• Weed Control• Pest Control

Location

• Near water supply for easy access

• Full sun- some plants will grow in shady areas (leafy greens, pumpkins)

• Away from trees- rob nutrients from veggies

• Flat land to prevent runoff and erosion

Soil Types

• Best garden soil is loam= equal amount of sand, silt, and clay– Good drainage so oxygen is available for roots– Organic matter to hold moisture and provide

plants with nutrients– pH range should be from 6.3-7.0 for most

veggies

Loam soil is ideal

Earthworms are a sign of good soil health

• Stimulate microbial activity

• Mix and aggregate soil • Increase infiltration • Improve water-

holding capacity • Provide channels for

root growth • Bury and shred plant

residue

Soil Management Practices…

• Clay Soils– Work up in the fall of the year– This allows drier soil in spring for earlier

planting– Prepare “raised beds” to plant early in season– Work manure, residue, and leaves into soil to

increase organic matter

Soil Management Practices…

• Sandy Soils– Best when planted with a fall cover crop, rye or

vetch and the worked in early spring– This adds organic matter– Helps to hold on to moisture and residual

nutrients– Soil tests should be done each year to

determine nitrogen, phosphorus, and potassium levels as well as pH level.

Soil Management Practices…

• pH is too high (alkaline)– Add sulfur to recommended amounts from soil

test

• pH is too low (basic)– Add lime to recommended amounts– How much to apply? Don’t guess soil test!– Beans, peas, onions require high pH levels

Feed the Soil• Plant get their essential nutrients from soil – either

mineral or from organic matter. Soil fauna is essential to this process;

• Plants don’t require a season’s worth of nutrients all at once, like we don’t eat all our meals at once;

• Synthetic fertilizers are typically salts, which dissolve rapidly in soil solution– Can aggravate a soil salinity problem;– Nutrients may be lost before plants use them;– Nutrient level fluctuation can negatively affect soil

microbial ecosystem.

Composting

Compost Ingredients

Get compost analyzed• Will need to know the elemental makeup of the

compost to determine amounts to use to meet the crop nutrient requirements

• Should be tested by a laboratory for moisture and nutrient content.

• Nutrient analysis should include: total nitrogen (N), ammonium-N, phosphate (P2O5), and potash (K2O).

• Accurate manure or compost analysis requires that a representative sample be submitted; so several subsamples should be collected and composited to make up the sample.

• If manure or compost is being purchased, request a nutrient analysis from the seller for N, P2O5, and K2O content.

Fertilizing• Plant Food Elements analysis is needed

(even for organic fertilizers)

N-P-KNitrogen % Phosphorus %

Potassium %

5-10-5

Fertilizing

• Why important to know % of elements?• For you know how much to feed your crops.• Like a diet calculator for your plants• Applying rates that are too low can lead to

nutrient deficiency and low yields. • Too high of nutrient rates can lead to nitrate

leaching, phosphorus runoff, accelerated eutrophication of lakes, and excessive vegetative growth of some crops.

Fertilizing Continued

• High Nitrogen Crops– Leafy veggies and corn

• High Phosphorus Crops– Pod and fruit crops

• High Potassium Crops– Root crops

Applying Fertilizers

• Broadcasting- spread amount of fertilizer equally over the entire garden and mix into soil before planting

• Sidedressing- Mix half into the soil before planting and apply the rest later in the season on top of the soil on each side of the rows about 3-4 inches from the stem.

Applying Fertilizers continued

• Banding- place the fertilizer in rows dug 3 inches from each side of the row of seeds or plants and slightly deeper than the depth planted.

• Plowing Under- if soil is very low in “P” and “K”, then add nutrients and plow under. Top dressing does not allow nutrients to be leached into soil fast enough.

Season Extension

• Interplanting method- plant a short term crop with a longer term plant so more crop can be grown in a smaller space. (i.e radishes and carrots, corn and pumpkins)

• Succession Planting- if using short term varieties, plant-harvest and replant another crop quickly to get maximum use of garden space.

Season Extension

• Crops can be planted at intervals of every two weeks so that they can be harvested throughout the season- less disease and insect pressure

• Replant areas where early crops, such as peas and lettuce are harvested with fall crops, such as kale or turnips. (succession)

• Use black plastic or mulch to cover ground to warm the soil and to keep weeds down.

Vegetable Crops: Increased Revenue and Cash Flow is our Goal

• Season Extension- early and late field plantings as well as mid season

• Increased early and late season market demand

Vegetable Crops: Increased Revenue and Cash Flow is our Goal

• High $ fall market especially last 2 years due to hurricanes in the south

• May have better size/quality, less disease/insect pressure in several plantings compared to continued harvest of main season plantings

Plasticulture Production Techniques

Season Extension- Zip House Performance

Floating Row Covers for freeze/frost protection

Staking and tying

• Prevent plant lodging under heavy fruit load

• Prevent plant lodging under wet soil conditions

• Prevents plant breakage under heavy fruit load

• Prevents wind damage to plant

• VERY LABOR INTENSIVE

Use of landscape fabric or weed matt

High Tunnels

High tunnel production

• Earlier harvest

• Higher fruit quality

• Dry plants= less disease

• Season extension

Sweet Corn Plastic Mulch Systems

• Potential benefits of clear plastic mulch

– Crop may mature 7-10 days earlier than unmulched

– May retain soil moisture (any mulch)

Crop Rotation

• Decreases insect/disease problems• Utilize nutrients already in soil provided by

previous crop• Example rotation

– Green, manure crops– High nitrogen crops, corn– Root crops– Solanaceous

• Back to beginning

Planting Methods

• Use fresh seeds from a reputable source

• Pay attention to last frost date in your area

• Plant according to directions on package

• Build “mini greenhouse” to protect seedlings from frost, increase germination rate/date, and increase temperature from sun so gardening can be started early in season.

Weed Control

• Don’t delay! Remove weeds when they are less than 1” tall and remove roots, too!

• Mulching/cover crops- straw, leaves, black polyethylene plastic, grass clippings, wood chips (nontreated) work well to control weeds and keep crops clean

Weeds• Annual weeds:

– Don’t delay! Cultivate before or soon after soil emergence roots and all!

– Smother with mulch (before or after weed seedling emergence);

– Flame weeding can work well but BE CAREFUL especially during the current drought.

• Mulching/cover crops- straw, leaves, black polyethylene plastic, grass clippings, wood chips (nontreated), newspapers, etc. work well to control weeds and keep crops clean

• In general: – Young weeds are easier to control by whatever

method.– Weeds can be composted, or used for mulch, if

they haven’t set seed.– If they have set seed, dispose of by burning,

burying, or similar solution.– Some weeds can harbor diseases.– Soil solarization can kill weeds and seeds at the

soil surface.

Soil Solarization with clear plastic:• Till soil, wet up real well;• Cover with heavy-duty clear plastic, anchored along

all edges;• Leave in the sun for several weeks to heat sterilize

upper inches.• Kills insects, eggs, seeds in the heated soil.• Poor control into deeper soil profile

Perennial Weeds

• Harder to control, as a rule

• Mulching can help

• Repeated cultivation and/or flaming can help

• Crop rotation, green manuring, etc. can help.

Don’t park the cultivator!!

Black Plastic Mulch• Warms soil earlier

• Suppresses weed growth

• Holds soil moisture

• Prevents soil splashing

• Cleaner fruit

• Can reduce disease

Raised beds, black plastic mulch & drip irrigation

Staking and Tying

• Florida Weave System

Staking Peppers

• Bell peppers should be staked to create a more upright canopy and reduce the risk of wind lodging

• Similar to tomatoes

Why use cover crops?• Add OM back to soil…• Reduce erosion…• Control weeds…• Conserve soil

moisture…• Control soil-borne

disease…• Increase fruit

cleanliness / quality at harvest…

Loss of SOM as CO2

Conventional agriculture is related to soil, air and water quality degradation

Acceleratednutrientsrelease(e.g. N)

Leaching, runoff andvolatilization of Nutrients with Conventional soil tillage

Chemical fertilizers dilemma

• Environmental crossroads

• Fossil fuelsAvailabilityCostPolitics

• N fertilizer production cost

Croprotation

Covercrops

No till

Cover Crops• Common types of cover crops

– Winter sown rye (annual)• Excellent biomass, sown in Fall

– Perennial rye grass• Good biomass, sown in Fall

– Hairy Vetch• Legume (+N), can be hard to kill

– Spring sown oats• Fall sown = very little biomass, spring sown = ok

biomass

• Not so common– Medics (annual legume from Australia)

• Fall seeded deteriorate over winter, spring seeded competes with crop

Benefits of cover crops

Common Mistake…Common Mistake…Seed is not placed in soilSeed is not placed in soilStrategy for success…Strategy for success…Plant to correct depthPlant to correct depthRoll before cover lodgesRoll before cover lodges

We have evaluated 32 different cover crops at OSU South Centers at Piketon for their suitability for:

-Biomass and nutrient management

-Biomass N contribution

-Nutrient recyclers

• Other characteristics

Cow peas

Alfalfa-timothy

Clover

Crimson clover

Austrian winter peas

Hairy vetch

Hairy Vetch- Fertilizer equivalent biomass N contribution ~ 80.6 + 4 lbs ac-1

Sudan-sorghum grass

Cereal rye

Sesame

Buckwheat-annual rye

Annual ryegrassFantasticStarfire

Cover cropsCpeas CClov HVetch LClov RClov Rgrass Rye Wpeas

Bio

mas

s (lb

s ac

-1)

0

5000

10000

15000

20000

25000

Fresh Dry

Cover cropsCpeas CClov HVetch LClov RClov Rgrass Rye Wpeas

N c

onte

nt (%

)

0

1

2

3

4

Cover cropsCpeas CClov HVetch LClov RClov Wpeas Rgrass Rye

N fe

rtili

zer

equi

v. (l

bs a

c-1

)

0

50

100

150

200

250

Total N fertilizer equivalent Biological N fixation

Soil

dept

h (in

)

Nitrate conc. (ppm)Hemphill and Hart (1993)

No cover crops Annual rye grass

Cover crops killing

5% vinegar @35 gallons ac-1

Roll over

Roundup

Challenges with cover crops:

Not a “Magic bullet”

Unable to replace chemical N fertilizers

Delay planting/poor germination

Initial lower crop yields (Transitional effect)

Challenges…..

Difficult to establish good stands

Compete with crops for nutrients

Immobilize soil N

Right combination (allelopathy)

Poor stand and persistence of hairy vetch as cover crops

Soil heaving effect onlarge seeded wintercover crops

Example: Austrian winter peas

Cons of using cover crops…

• Having field available in fall.• Extra costs and labor needed.• Chemicals will still need to

be used.• Cooler, wetter soils• Increased chance of

herbicide injury? • Longer production

schedules.• Vertebrate damage increases

Continue to look for appropriatecover crops for your farm

Vegetable Crop Disease Management

• Use IPM approach - multiple tactics• Manage water properly

– Trickle/drip irrigation better than overhead– Use raised beds

• Select best possible site– Open (good air movement), well-drained

• Improve soil quality– Organic amendments– Cover crops

• Practice appropriate rotations– Rotate away from similar crops at least three years

• Choose varieties with best resistance available– “Mountain” series: moderate resistance to early blight

(Mountain Pride, Supreme, Gold, Fresh and Belle) – Clean Seed

Disease Triangle

Disease Management

• Use IPM approach - multiple tactics• Select best possible site

– Open (good air movement), well-drained

• Improve soil quality– Organic amendments– Cover crops

• Practice appropriate rotations– i.e Tomatoes- Rotate away from solanaceous crops at

least three years

Pest Control/Prevention

• Dispose of crop residue (leftovers)

• Rotate Crops

• Use “treated” seeds

• Use “resistant” varieties

• Purchase healthy transplants

• Use limited chemicals if necessary– STAY SAFE…READ the DIRECTIONS!

In the Field - Cultural Tactics

• Mulches– Plastic or plant-based

• Reduce splash dispersal of pathogens• Protect fruit from soilborne pathogens

• Row orientation– Maximize air movement– Minimize leaf wetness periods

In the Field - Sanitation

• Destroy plant tissue post-season– Removes sources of inoculum

• Remove diseased plants and weeds in-season– esp. for late blight, bacterial diseases

• Sterilize plant stakes between crops• Clean tools, equipment frequently• Prohibit tobacco use

Watering and Irrigation

• Timeliness is important• Mother Nature does not always provide

moisture in a timely manner• Rule of Thumb= 1 inch of water per week• More or less required at different stages of

crop growth• Need to account for evapotransporation and

rainfall

Drip Irrigation

• Low volume requirements• Low pressure requirements• Put the water where the plant needs it the

most

Overhead Irrigation• Easy to manage

• Plant wettness

• Good for evaporative cooling of plants

• Large water volume required

• Large pressure and horsepower requirements

Direct seeding or transplanting?• Some plants don’t take transplanting well

(cucurbits, root crops, beans and peas).

• Some do (tomato, pepper, eggplant, greens of all types, early corn).

• Can gain 2 to 4 weeks by transplanting, depending on soil temperatures and crop.

• Cost, hassle trade-offs.

• May help get ahead of weed problems.

Use Clean Seed

• To control bacterial diseases

• Tomato seed are acid treated during processing/de-fuzzing– Not fully effective in sanitizing seed

• Other options– Clorox treatment (surface sanitation)– Hot water treatment (surface & internal)

Produce Clean Transplants

• Practice good sanitation in the greenhouse– Use new or sanitized

plug trays or flats and pathogen-free mixes

– Sanitize equipment– Install solid flooring;

raise seedling trays– Limit movement of

personnel and equipment between greenhouses

– Clean benches, greenhouse structure thoroughly after the crop

• Do not raise exotic or experimental vegetable varieties, or plants from saved seed, in the same greenhouse with commercial seedlings unless all seeds are treated

• Avoid raising or holding ornamental plants and vegetables in the same greenhouse

• Exclude insects (may carry viruses)

Produce Clean Transplants

• Maintain conditions in the greenhouse that do not favor disease development

– Maintain relative humidity as low as possible• Good air circulation• Proper temperatures

– Do not overwater

– Handle plants as little as possible

Produce Clean Transplants

Transplants

Larger cell size=earlier harvest

Vegetable Variety Selection

• The most important grower decision

• Grower experience is the best

• Variety evaluation is VERY TIME CONSUMING

• Consider all the factors

• Start with new varieties on a small trial scale first

Variety Selection• Use of “Adapted Varieties” or those have been proven to

grow well in this region– unadapted can lead to loss of 20% yield

• Study data from 3 years or more using regional variety trial results and your own on farm testing

• Agriculture Experiment Station field days and trials– summaries released yearly

• Private Seed Companies field days and trials• It takes 8-10 years for variety development, 2-3 more for

commercial production

On farm variety testing

Variety Adoption

• Market Acceptability: plant product must have characteristics desired by the buyer including size, shape, color, flavor, and nutritional quality

• Adaptability: Varieties must perform well under the range of environmental conditions usually encountered on the farm (drought, heat, cold, wet, wind)

Variety Adoption (cont.)

• Horticultural Quality: characteristics of the plant habit as related to climate and production practices of the plant product

• Concentrated set for machine harvest pickles, tomato, sweet corn, green bean.

Variety Adoption (cont.)

• Disease Resistance or tolerance: this is the most effective means of pest management (less costly than chemicals)

• Genetic resistance or tolerance to disease or insect• Virus masking in squash• When all other factors are equal it would be prudent to

select for resistance or tolerance

Variety Adoption (cont.)

• Yield

• The variety should have the potential to produce crops at least equivalent to those varieties already being grown

• Harvested yield may be much less than potential yield because of market constraints

Horticultural Quality Characteristics

• Quality traits of crop may be more important than yield characteristic

• “Super Sweet” sweet corn varieties

• Fruit size, color

• Spineless in squash

• Thornlessin blackberry

Want to Learn More? University trials and Field Days

Seed Company Field Days

Midwest Vegetable Variety Trial Report

•Reports from Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, North Dakota, and Ohio are included.

• Online:. http://www.hort.purdue.edu/fruitveg/reports.shtml

• To purchase:Purdue University Media Distribution Department. Tel: 1-888-398-4636.A new bulletin is published each year reflecting current season's trials from Midwestern states. Past issues are sometimes available.

Full reports of this and past years results:

• Brad BergefurdExtension Educator, HorticultureOSU South Centers1864 Shyville RoadPiketon, Ohio 45661bergefurd.1@osu.eduhttp://southcenters.osu.edu/hort/1-800-860-7232

• (614) 292-4900