|
|
|
|
 |
Water quality is very important in greenhouse production.
You should have both of your water sources analyzed
by a professional lab. Monitoring pH, electrical conductivity
(EC) and alkalinity of your water are keys to successfully growing
horticultural crops. Water quality often influences your fertilization
program, site selection and even which crops you can grow. All
growers should know the following: water pH, media pH, alkalinity
of irrigation water, EC of irrigation water, EC of irrigation water
plus water soluble fertilizer and EC of your media. |
|
While it is important to have your water tested annually
by a professional lab, growers should also repeat tests
themselves throughout the growing season using a pH & EC
hand held meter as well as an alkalinity kit. |
|
The pH of growing media drives chemical reactions
and nutrient uptake by the plant roots. In general, the
initial optimum container media pH range is from 5.8 to 6.4
(depending on your crop). Water pH influences media pH,
but in most cases water pH does not equal media pH. Water
pH also affects soil microbes and effectiveness of pesticides
and growth regulators. Most successful growers continuously
monitor the pH of their water as well as the pH of their media
throughout the growing season. |
|
Alkalinity is not the same thing as pH. Alkalinity is
defined as the capacity of the water to neutralize acids
and is measured by the amount of bicarbonates and carbonates
in the water. It will dictate how much influence the water’s
pH will have on your media, nutrient availability, and ease or
difficulty of reducing the pH of water. Alkalinity is expressed as
ppm calcium carbonate CaCO3. Most water sources acceptable
for container production will have alkalinity in the range of
0 to 400 ppm CaCO3. Growers of bedding plant plugs should
pay close attention to pH and alkalinity, as media pH can rise
rapidly and potentially cause iron deficiency symptoms. |
|
Electrical conductivity is the measurement of a solution’s
ability to conduct an electric current. Electrolytes
in the water determine its level of conductivity. Over time,
high water electrical conductivity can ruin good soil. Electrical
conductivity is an excellent indicator of water quality, soil salinity
and nutrient levels. Electrical conductivity can be measured
by a hand held electrical conductivity meter. A good Electrical
conductivity range for irrigation water is 0 to 0.75 milliSiemens
per centimeter. A good reference for greenhouse water quality
issues is “Water, Media, and Nutrition for Greenhouse Crops”
edited by David Wm. Reed, Ball Publishing. |
|
|
|
|
|
