| Phase Change | What can you expect? | Protection limits | Guidelines for use | Improving fruit set | Agrofrost vs. science | Wet and dry temperature |
Protection Limits
The temperatures in the table below are the minimum temperatures where our machines still had good results. The data in the table below are not “absolute” values. We regularly adapt these values, based upon new experiences from our customers and from some Research Centres.
The critical temperatures also depend on the stage of flowering and the size of the fruits. For example: we had good results at -8 to -9 °C in pears in the stage “white bud”, while the table here shows -5,5 °C for “full flowering”. So in certain flowering stages, the minimum temperatures where we can provide protection are lower.
| Frostbuster | FrostGuard | Wind machine * | ||
|---|---|---|---|---|
| Radiation Frost | Relative Humidity | |||
| Full Flowering | > 85 % | - 5,5 °C | - 5,5 °C | - 5 °C |
| Full Flowering | < 85 % | - 3,5 °C | - 3,5 °C | - 3 °C |
| Fruits | > 85 % | - 3,5 °C *** | - 3,5 °C *** | - 3,5 °C *** |
| Fruits | < 85 % | limited result | limited result | limited result |
| Vineyards | > 85 % | -2 to -3.5 °C ** | -2 to -3 °C ** | -2 to -4 °C ** |
| Vineyards | < 85 % | limited result | limited result | limited result |
| Wind Frost | Relative Humidity | |||
| Full Flowering | > 85 % | -4,5 °C ****** | -4,5 °C ****** | limited result |
| Full Flowering | < 85 % | limited result | limited result | limited result |
| Fruits | > 85 % | -3,5 °C ****** | -3,5 °C ****** | limited result |
| Fruits | < 85 % | limited result **** | limited result **** | limited result |
| Vineyards | > 85 % | -2 to -3 °C **** | -2 to -3 °C **** | limited result |
| Vineyards | < 85 % | limited result **** | limited result **** | limited result |
* = the capacity of a wind machine depends a lot on the temperature, the eventual use of an extra heating system, the hight of the trees and of course of the quality of the inversion layer. The protected area from our wind machine varies between 2 to 4 ha at -5 °C and 6 to 7 ha at -3 °C. In case of negative inversion, the wind machine should not be used because it will create even more damage.
** = depends a lot on the phenological stage of the plants: the smaller the buds, the more difficult to protect. We advise to combine the Frostbuster and FrostGuard with paraffin candles, certainly in the stage of bud burst or first leaves.
*** = also depending on the type of fruits, the size of the fruits, humidity, wind. Small fruits are very difficult to protect.
**** = in case of wind frost or a combination of wind frost with radiation frost, always put paraffin candles around the area that needs to be protected.
****** = put paraffin candles on the wind side to improve results, certainly with the FrostGuard.