Water Requirements in Horticulture Crops - Frequently Asked Questions

 
 
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 How much water does my horticulture crop require? When is the best time to water (when is adequate moisture critical)? 
The amount of water used by a particular crop depends on a number of factors, including crop growth stage and environmental conditions (temperature, wind, relative humidity).  The speed at which soil moisture is depleted depends on crop use and the soil type (sand, clay, etc.).  Applying adequate amounts of moisture requires a basic understanding of soils and the general water use of the crop.  Moisture stress/excess can influence crop yield and survivability (over-wintering).

Table 1: Critical periods and water requirements of Fruits and Vegetables

VEGETABLES
CROP
CRITICAL PERIOD
WATER REQUIREMENTS
AsparagusDuring establishment
During harvest
Apply approx. 50 mm after harvest
Apply 25 mm at the end of the season
Apply 25 mm every 10 days (depending on precipitation)
BeansDuring flowering and pod setApply 25 to 38 mm per week during peak use period*
CarrotsGeneral growth and root fillWill use 4 to 6 mm per day during peak use period
Cole Crops (Broccoli, Cabbage, Cauliflower)Head formation and enlargementWill use 380 to 500 mm during the season*
CornTasseling, pollination and ear fillingWill use up to 6 mm per day (during peak use period)
Will use up to 510 mm during the season*
CucumbersFlowering, fruit set and development
During rapid growth and fruit sizing
Apply 25 mm after seeding/transplanting
Don’t allow to dry out during critical period
Will use approx. 200 to 250 mm during the season*
EggplantFlowering, fruit set and enlargementApply 25 mm per week*
GarlicBulb formation and enlargementApply 25 mm per week (minimum)*
LettuceGermination and throughout growthDon’t allow soil profile to become depleted
Muskmelon/ CantaloupeFlowering, fruit set and developmentApply 25 mm after seeding/transplanting
Don’t allow to dry out during critical period
OnionsBulb formation and enlargementWill use 4 to 5 mm per day (during peak use)
Apply 25 mm per week*
Will use 350 to 500 mm during the season*
PeasFlowering, pod set and fillWill use 5.5 to 6 mm per day (during peak use)
Will use 375 mm during the season*
PeppersFlowering, fruit set and enlargementApply 25 mm per week* (depending on soil type)
PotatoesTuber initiation and sizingWill use 5.5 to 6 mm per day (during peak use)
Will use up to 550 mm during the season*
PumpkinsFlowering, fruit set and developmentApply 25 mm after seeding/transplanting
Don’t allow to dry out during critical period
RadishesRoot fillDon’t allow to dry out
TomatoesFlowering, fruit set and enlargementApply 25 mm per week*
ZucchiniFlowering, fruit set and developmentApply 25 mm after seeding/transplanting
Don’t allow to dry out during critical period
FRUIT
CROP
CRITICAL PERIOD
WATER REQUIREMENTS
Strawberries
(June bearers)
After planting (during establishment)
During flowering, fruit set and fill
Don’t allow soil to dry out
Apply 6 to 8 mm every 2 days*
Apply 25 mm per week after mowing (renovation)*
Strawberries

(Day neutrals)

After planting (during establishment)
During flowering, fruit set and fill
Don’t allow soil to dry out
Apply water in frequent, light applications
Initiate field cooling to improve fruit set in high temperatures
RaspberriesAfter planting (during establishment)
During flowering, fruit set and fill
Will use approx. 5 to 8 mm per day (during peak use period)
Apply 25 to 37 mm per week from blossom to harvest*
Saskatoon berriesAfter planting (during orchard establishment)
During flowering, fruit set and fill
Will use 160,000 to 180,000 litres per acre per year
Currants/
Gooseberries
After planting (during orchard establishment)
During flowering, fruit set and fill
Ensure supply of approx. 25 mm per week
* Including precipitation

Tips for reducing water application requirements

  • Use some form of mulch [plastic, organic (straw, bark, shavings)]
  • Apply the water either directly to the plants (through a drip system) or using a lower pressure applicator (versus sprinkler application)
  • Apply water in the early morning or evening when temperatures are lower (to reduce evaporative losses)
  • Provide adequate nutrients to ensure healthy, deep-rooted plants which maximise water use within the soil profile

Prepared by Robert Spencer, Ag-Info Centre, Alberta Agriculture and Rural Development
 
 
 
 
For more information about the content of this document, contact the Ag-Info Centre.
This information published to the web on August 5, 2003.
Last Reviewed/Revised on November 27, 2013.