Changes in Rosavins levels with temperature and root conditions
ARRGO has been observing changes in rosavins levels which may correlate to temperature and dormancy conditions in Rhodiola root. It may be possible to use this information to simulate conditions which will affect the rosavins levels in harvested crop.
ARRGO tests each grower’s crop before the grower can deliver their Rhodiola for processing. The pre-harvest test must meet minimum criteria for rosavins. Once this minimum is achieved the grower is given the ‘go’ to start digging.
In past years the rosavins levels have showed some change between the pre-harvest test and the final production test. ARRGO is now taking a deeper look into the reasons behind those changes.
The weather during autumn in Alberta can be unpredictable as we move from warmer to colder temperatures. Fall 2020 was no exception. Fall is also the time when ARRGO asks its members to harvest. Last fall Southern Alberta temperatures in mid-October went from balmy +20 deg C to chilling nighttime lows of -20 C for a period long enough to send frost several inches into the ground. In late October and early November nighttime temperatures rebounded to +7 C, and the Rhodiola harvest was resumed for some farmers.
The early onset of colder weather in October 2020 may have caused rosavins levels to fall well below the pre-harvest test numbers. Some root was delivered in a frozen state. ARRGO recognizes that the root is still very much alive when it is delivered, and that the condition of the root may indicate its state in the cycle of dormancy and growth.
ARRGO noted that early production tests of crop harvested after the cold snap in October were significantly lower than pre-harvest tests. ARRGO Operations Manager, Stephanie Cain, felt that the fast freeze had induced a dormant state and suggested that ARRGO should allow the harvest to undergo simulated winter in our refrigerated storage.
Fast forward to January and the crop is brought out of cold storage and allowed to slowly thaw for one week. Growth buds start to swell and the crew starts processing the crop for our customers. After one week production tests show that the rosavins have rebounded, but are still below the pre-harvest levels. After one more week, the buds are bolting and green (as pictured) and rosavins have jumped 10% from the previous week’s production test.
What is really happening? Only the Rhodiola knows. . .for now. But possibly the seasons can be simulated to provide the best results for our customers.