Garden with Insight
Garden with Insight v1.0 Help: Plant next day functions: if perennial, check to see if should be dormant
One of the ways perennial plants stay alive during periods of bad
weather (cold and/or dry seasons) is to become dormant. Actually, some animals become dormant
(hibernating bears in cold weather, aestivating frogs in dry weather) and most bacteria enter a dormant
"spore stage" when conditions are dangerous.
If the simulated climate contains at least one month whose long-term
average minimum (night) temperature is below 5 degrees C (41 degrees F), perennial plants go into
a dormant phase. The length of the dormant period is determined by
day length. Dormancy begins when the day length falls below the
minimum day length for the year plus some amount. That amount is set to a constant of one hour in this
Dormancy is simulated here by not calculating the daily growth equations. Above-ground biomass can still be reduced due to frost, short day lengths, and water
stress, but root biomass remains intact. On the 15th day of the coldest month of the year the accumulated
heat units of all perennial plants are reset to zero (and their heat unit index is reset as well). When the dormant period is over and the
temperature warms up, perennials are ready to begin rapid new growth, because all of the processes that
depend on heat unit index (allocation to shoots, vegetative growth, increasing leaf area index) are reset.
Note that the simulation does not model any type of dryness-induced dormancy. This is not usually an
issue for gardens because adequate water is provided by irrigation.
calculation of potential biomass increase, damage from frost and short day length, damage from water stress, allocation to
EPIC Winter Dormancy