Strategies for Site Selection of Orchards & Vineyards

Eric T. Stafne Associate Extension Professor Fruit Crops Specialist Mississippi State University Poplarville, MS

“You can have the most beautiful plant in the world, but if it won’t survive outside, it’s worthless”.

Hardiness Zone Map

Climate Scales

Macroclimate – large geographic region

Mesoclimate – local climate

Microclimate – specific environment around the plants Related to plant growth and development post-

site selection decision

Macro Site Selection Considerations

Length of growing season

Coolness of the dormant season (chilling)

Frost

Frequency of extreme low temperatures

Summer high temperatures

Precipitation

Length of Growing Season

Some fruit crops may not ripen if growing season is too short Some grapes (especially red

varieties) need longer season to fully ripen

Some pecan varieties will not ripen until November or later thus being potentially exposed to shuck freeze damage

http://northernpecans.blogspot.com/2011/11/why-wont-some-pecan-shucks-split-open.html

Chilling Requirement A chill hour can vary depending on the model used, but the

most common model defines it as the number of hours below 45 °F

This is a requirement for the plant to satisfy its dormancy and thus to grow and fruit normally the following year

In regions where cold temperatures are more common, plants can remain in a quiescent (waiting for a warm up) phase even after their chill hour requirement has been met

However, in warmer climates this may not be the case, so early flowering is a problem in low-chill varieties

Frost

Can be damaging early in the growing season (bloom) and late in the season (pre-hardening off)

Choose sites with low likelihood of these events

Photo by B. Carroll, Oklahoma State University

Frequency of Extreme Low Temps

Some fruit crops are not very winter hardy

Very important for growing species/varieties on the fringes of their adaptation

Often other varieties or species are available to overcome this issue

Citrus Cold Tolerance (°F)

Kumquat 16-17 Satsuma 18 Calamondin 21-23 Orange, grapefruit 23-24 Lemon 26-27 Lime 28

Fruit potentially damaged below 32 °F.

Summer High Temperatures

Extreme high day and night temperatures in summer can limit some species

Fruit quality may suffer as respiration exceeds photosynthesis

Flowering inhibited when temps over ~80-85°F Primocane-fruiting blackberries Red raspberries (esp. fall-fruiters) Strawberries

Primocane-Fruiting Bramble Varieties

Not recommended for commercial production, rather for home garden use and limited commercial trial

Poor performance for primocane crop in high heat Heat in late July to early Sept. greatly reduces fruit set,

quality, and yield Appears that temps of ~85 oF for several consecutive

days cause these problems, and even later-season cool temperatures do not bring the fruiting potential back strongly

Precipitation What is the average annual rainfall?

When does it normally fall?

Is drought a common occurrence?

Is flooding a common occurrence?

Many fruit species do not tolerate standing water for extended periods of time (for example: stone fruits and blueberries)

Some fruit species can tolerate drought conditions, but not for long periods of time (for example: pears, pecans, blackberries)

Meso Site Selection Considerations

Elevation Topography Slope Aspect Prior land use Soils Pests and other threats

Elevation

Can have a big influence on minimum and maximum temperatures in orchard/planting area

One of the most important considerations before planting

In much of Mississippi look for “relative” elevation on site and plant near highest point

Important for frost mitigation

Low Elevations

• More prone to frost

• Less air movement

• Poorer water and air drainage

• More prone to disease

Photo Mississippi State University Extension Service

Topography

Includes the “absolute” elevation of a site

How many feet above sea level?

Slope

The percent inclination or declination that varies from horizontal

Slight to moderate slope is desirable

Important for cold air drainage

Also for water drainage

Steep slopes (>15%) not recommended due to difficulty in equipment use and erosion potential

Water Drainage

Surface drainage is most important; avoid standing water

Internal drainage is related to soil characteristics Stone fruit and blueberries are intolerant of wet

soil

Best planting location often is on top of a hill or on a slope

Raised beds compensate for poorly drained soils

Good Drainage Situation

Photo Mississippi State University Extension Service

Poor Drainage

Photo Mississippi State University Extension Service

Air Movement

The more air drainage, the better

Air movement provides disease and frost protection

Avoid hedgerows on the lower side of the orchard

Aspect In reference to the slope – what is the

prevailing compass direction that the slope faces?

Aspect affects sunlight angle interception

Not as important as some other considerations

If possible, eastern exposure (or NE, SE) is better than western exposure

Aspect Attributes

East = early morning sun that dries off foliage, starts photosynthesis earlier, cooler, later budbreak in spring

West = hottest, late day sun exposure

South = also hot during summer, may promote earlier budbreak in spring, longer growing season

North = cooler during summer, later budbreak in spring, colder in winter, shorter growing season

Light Requirements

• Full sun is ideal

• Morning sun is preferable to afternoon sun

Prior Land Use

Compacted soils

Prior crops grown on site Nematodes

Root rot fungi

Pesticides used before

Soils For Fruit & Nut Trees

Depth Effective rooting depth May be limited by rock, water Minimum of 3 feet in most cases Slightly acidic soil best

Drainage Internal: berm, perk test External: slope to open area

http://www.nrcs.usda.gov/wps/portal/nrcs/detail/ak/soils/surveys/?cid=nrcs142p2_035915

Soil Types

http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-May0105.html

Soil Characteristics

• Ideal soil is well-drained with adequate water-holding capacity

• Sandy loams are best

• Poor soil is poorly drained (internally or externally), and pH is not correct for the crop

Photo Mississippi State University Extension Service

Soil pH

http://www.lsuagcenter.com/en/lawn_garden/home_gardening/Understanding+and+Improving+Soil+Fertility.htm

Pests and Other Threats

Disease Insects Weeds Animals Birds Allelopathic plants Neighbors

Variety Selection

• Adaptability to your area - very important

• Disease resistance

• Self-pollination versus cross-pollination

• Desired harvest date

• Taste, sweetness, size, texture, etc.

The Variety Equation

What does it take to select and maintain an appropriate variety?

AV = [(G x E) +((SS x M) + LE))]xL

where:

AV = Appropriate Variety

G = Genetics

The variety must have the necessary genetic elements to succeed

E = Environment The environment will interact with the genetic

components of the variety to impact the outcome, i.e. yields, quality, and survival

SS = Site Selection Fruiting plants placed on the wrong site, including

considerations like water availability and quality, soil quality, nutrient availability, air and water drainage, accessibility, etc. will dictate final outcomes

M = Management

Good management can help offset some factors such as less than optimal site selection and improve plant health and fruit quality

LE = Learning and Education Education should be a never ending task for a

fruit grower, but a good knowledge of the basics should be garnered before putting a plant in the ground

L = Luck All of the best laid plans can be disrupted with

bad luck — drought, freezes, broken pumps, plugged emitters, birds, plague of locusts, etc., because once your luck turns to zero, so does your AV

Some Examples Concord grape – doesn’t tolerate heat well, susceptible to

PD

Flame Seedless grape – susceptible to PD

Highbush blueberries – not heat tolerant, high chilling requirement

Sweet Cherries – do not tolerate heat, high chilling requirement

Citrus – cannot tolerate much cold

News You Can Use

Mississippi Fruit and Nut Blog

http://msfruitextension.wordpress.com/

My email: estafne@ext.msstate.edu (best option)

My phone number: 601-403-8939

Twitter: @EStafne