ACCURATE, RELIABLE WEATHER information is essential for managing greenhouse and field-grown crops and ornamental plants. The right weather information helps you manage work schedules so you can reduce costs and maximize results.

You can't change the weather. but you can learn how to make the most of the weather you do have. We hope to help you learn to better profit from weather conditions.

Weather and plant/pest development
Some weather effects on plant production are obvious:  untimely frost, drought, hail, high winds or excessive heat can cause plant stress or, in the worst case, destroy an entire crop or planting. Less obvious effects include the weather's indirect impact on plants via its effects on insect, disease and weed pest development.

When it's warm outside, both plants and pests grow faster. That's because the speed of growth depends on the speed of chemical reactions going on inside all living things.

The "body" temperature of "cold-blooded" weed and desirable plants, insects, and disease organisms changes with the outside air temperature. Thus, when it's cold out, plants and pests are cold all the way through, slowing down chemical reactions and growth. They develop according to temperature, not the calendar.

If you're spraying according to the calendar, you're not getting the results you should.

For example, June 15 may be the "average" date the most susceptible stages of a pest appears, but an average year may occur only once in a decade. Most years are somewhat warmer or colder than average, resulting in faster or slower pest development and a "most susceptible" date for best spray timing up to 10 days before or after June 15.

By using temperature information , you can time sprays to hit the most susceptible stage every year.

Simple tools such as a Min/max thermometer and degree days can help you make the most of your pesticide dollars.

Finding weather information
You won't find the site-specific weather information you need to run an IPM program on the television news. However, weather details useful for scheduling pesticides, irrigation or frost protection can be almost as easy to access from other sources.

If you do a search for weather-related web sites, you'll find plenty of information, including detailed weather maps for scheduling activities, degree day accumulations for timing sprays, and crop-specific advisories on whether or when to spray for diseases.

Site-specific forecast
In addition to or in place of the Internet, a weather service provider can deliver weather data specific to your site right to your fax machine or e-mail of a daily basis.

For a monthly fee, these reports provide the usual forecast statistics such as air temperature, humidity and rainfall, but also dew, frost and drying potential, chill hours and degree days.

The reports will be more specific to your location than most weather data you'll find on the Internet, and can be ordered for just the months you need them.

Finally, you'll find tools on the following pages that can help you collect your own weather information. These include basic instruments such as Min/max thermometers and rain gauges, as well as sophisticated weather stations that report a wide variety of weather statistics measured at your location.

Weather parameters you can monitor