Planning for continuous harvesting of vegetable crops

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Planning for continuous harvesting of vegetable
crops
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Joel Gruver CEFS Student Farm Manager 2000
2001
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Why do vegetable crops develop at different rates
?
Crop genetics Crop management Weather
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Phenological time vs. chronological
time
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Crop genetics
General categories frost hardy vs. frost
sensitive determinate vs. indeterminate immature
vs. mature seeds cut and come again
greens multiple harvest fruits ratoon crops
Specific cultivars
Silver Queen Sugar Buns Jubilee Tuxedo
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• Long season crops
• Leeks
• Parsnips
• Pumpkins
• Brussel sprouts
• Sweet potatoes

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• Short season crops
• Radishes
• Kohlrabi
• Turnips
• Spinach
• Arugula

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Cut and come again greens Kale Lettuce Parsley
Swiss chard Turnip greensCollard Greens Mustard
greens Chicory/Dandelion
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Multiple harvest fruit crops Summer
Squash Tomatoes Peppers Eggplant Okra
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Fruit yield distribution
Percentage of total yield
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20
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1
5
3
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Weeks into harvest season
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Determinate vs. Indeterminate growth
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Ratoon cropping of sugarcane
Some vegetable crops can be ratooned e.g.
Eggplant, Okra, Peppers
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Variation between cultivars
http//www.rogersadvantage.com/products/corn_proc.
asp
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Managing the crop environment Tillage Raised
beds Plasticulture Row covers Natural
microclimates
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Effect of tillage on soil temperature
http//www.progressivefarm.com/html/figure2.html
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Effect of raised beds on soil temperature
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Effect of plastic mulch on soil temperature
http//www.fftc.agnet.org/library/image/eb332f4.ht
ml
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Effect of row covers on cabbage yield
http//www.fftc.agnet.org/library/image/eb332t4.ht
ml
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• Deciding when to plant
• Look up recommended planting dates
• http//ipm.ncsu.edu/vegetables/CommercialVegetable
  s/
• 2) Monitor soil temperature
• 3) Use backwards planning

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Recommended planting dates
http//ipm.ncsu.edu/vegetables/CommercialVegetable
s/
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http//aggie-horticulture.tamu.edu/extension/vegha
ndbook/appendix/table5.html
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• Backwards planning
• Identify harvest goals
• Plan necessary field activities to achieve
  harvest goals

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Planning on paper
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Fine tuning your planning
Heat Unit Accumulation
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Calculating Heat Units
(Min Temp Max Temp) / 2 - Base Temp
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Scheduling sweet corn plantings for continuous
harvesting
Second planting
First planting
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Goal harvest corn each week
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Rule of thumb Wait until seedlings are 2 tall
before next planting
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http//aggie-horticulture.tamu.edu/extension/vegha
ndbook/appendix/table9.html
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Using electronic spreadsheets for planning
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Identify the weeks when you think that it will be
possible to harvest each crop
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Plan production activities based on weekly
harvest goals
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Special Thanks to
Theresa Nartea and all the staff at the Center
for Environmental Farming Systems in Goldsboro, NC
http//www.soil.ncsu.edu/lockers/Gruver_J/