Raised Bed Gardening Blog

Early bud freeze

Created on Sunday, 16 February 2014 09:19

Early bud freeze. Something all of us cringe to hear. Last year was a total bust for fruit here in Santa Fe, and the way this mid-Winter is warming up, the possibility exists once again. There are actually two types of frost- advective and radiative- that can destroy your crops. Advective frost is cold air from another region that moves into an area and winds remain relatively strong. Radiative frosts are produced locally, and occur only during clear, calm nights. Growing late-flowering varietals is one way to partially counter killing frosts. Soil moisture is a second concern. Excessively wet soils gain less heat energy during the day, as more of the sun's energy goes into evaporating moisture. This can reduce the heat available to the crops at night. Excessively dry soils are poorer heat conductors, and are able to store less heat, and therefore result in a higher risk of frost. Mulches are another alternative. On the soil surface, they increase the risk of frost by behaving as insulators. Less heat is absorbed by the soil during the day, and less is released at night. Mulches can help to avoid freeze damage if they completely cover the sensitive plant parts. Covers are a passive way to reduce injury to young buds. Any cover is effective in reducing heat loss by convection. When covers are placed, particularly thin material like plastics, care must be taken to prevent contact with the plant to reduce heat loss by conduction, as the temperature of the exposed surface is usually lower than the air below it. Passive and active systems both have an effect on reducing freeze havoc on your crops. Siting your plants on a leeward side of the winds is a good, preventive start, as well as choosing hardier varietals. Working to alleviate climate change is probably the most important factor, as the temperature swings around the US get more radical, and weather situations leave hundreds of thousands of citizens shaking their heads, and waking up to the fact that 'the times they are a-changin'!