Boost Soil Biology to Protect Your Crops from Frost Damage
Frost damage strikes fear in the heart of cereal cropping farmers, but it doesn’t just affect cereal crops—it can impact all plants. In this blog, we’ll explore how frost damage occurs and how you can minimise its impact.
With the unusually warm autumn we’re experiencing, frost may feel like a distant concern. But preparation is key—and it’s never too early to protect your crops.
How does frost damage occur?
There are a few ways that frost can cause damage to plants. The severity depends on crop type, stage of development, and whether the canopy is wet. In essence, the damage can happen externally (on the outside) of the leaf or internally (within) plant tissue.
- External Frost Damage: When ice forms on the outside of leaves during low temperatures, moisture is drawn from the leaf surface, leaving it dry and brittle—this is called desiccation1.
- Internal Frost Damage: When water freezes inside plant tissue, plant cells shrink as water is forced out of the cell and into the spaces between them (intercellular spaces), where it forms ice crystals2.
Once temperatures rise and the crystals melt, water is absorbed back into the cells through osmosis. If this happens quickly, damage may be minimal. However, when thawing occurs slowly, cells become dehydrated, leading to a condition known as ‘frost burn’2.
When does the most damage occur?
Severe frost damage typically occurs in late winter and early spring, when plants are flowering or producing fresh foliage. At this stage, plants are especially vulnerable to damage caused by rapid thawing, particularly under strong sunlight.
What increases frost damage?
Several factors influence frost damage severity:
- Landscape and Microclimates: Valleys and hills can trap or divert cold air, creating frost-prone areas1.
- Bacteria & Ice Formation: Some bacteria living on leaf surfaces can increase frost damage by initiating ice formation. These are known as Ice Nucleation Active (INA) bacteria3.
- INA bacteria trigger freezing at higher temperatures, making crops more susceptible to damage.
- Research from the Department of Primary Industries and Regional Development found that INA bacteria on stubble produce proteins in cold and wet conditions, accelerating ice formation and frost damage4.
Impacts of frost damage
- Financial Cost – According to CSIRO, frost damage costs wheat farmers on average $360 million per year5. However, damage isn’t limited to cereal crops. Grazing and fodder crops are susceptible to frost damage, making them toxic to stock6.
- Toxicity – Summer annual grasses contain cyanogenic glucosides and these are converted to prussic acid when plants are damaged by frost and is toxic to stock.
- Bloating – Certain pastures release increased amounts of potassium, calcium and magnesium if cell walls rupture during a frost event6, and can result in bloat if eaten by stock.
How to minimise frost damage
As always, soil health is key to plant health and resistance/tolerance to both biotic and abiotic stresses – frost being abiotic, and by now you would know that biology is the key to soil health.
- Strengthen Cell Walls – Strong cell walls play a crucial role in improving plant health and crop protection mechanisms. Key nutrients—calcium, silicon, and boron7—are essential for reinforcing cell walls. These elements become more accessible through balanced nutrition and increased biological activity in the soil, which helps unlock nutrients naturally. A vermiwash, such as NutriSoil Biological Solution, provides a rich source of plant-available macro and micro nutrients, along with a diverse community of beneficial microbes. These microbes support nutrient delivery and contribute to plant cell health and defense, strengthening resilience against environmental stressors.
- Displace INA bacteria – on the leaf of the plant is another method to help minimise damage caused by frost, this can be achieved by applying beneficial bacteria to the leaf of the plant to outnumber the INA bacteria8. Pseudomonas fluorescens is one such beneficial bacteria, and is found in a vermiwash, like NutriSoil Biological Solution.
- Apply Biology – applying a vermiwash, such as NutriSoil Biological Solution, to your crop not only helps to increase the biological activity in the soil, but it also helps to ensure that harmful microbe populations are kept in check.
NutriSoil Biological Solution can be utilised as a seed inoculant during sowing and as a foliar application on pastures and cereal crops to enhance photosynthesis. With regular applications, customers have reported improved overall soil health, which leads to better tolerance of adverse biotic and abiotic stresses, such as frost.
Final thoughts
Frost is a challenging seasonal threat, but improving soil biology and crop health can make a significant difference. By strengthening plants from the inside out, farmers can reduce frost damage and enhance long-term resilience.
References
- https://www.agric.wa.gov.au/frost/science-frost-and-frequently-asked-questions
- https://apsvic.org.au/protect-your-plants-from-frost-damage/
- https://my.ucanr.edu/blogs/UCCESonoma/blogfiles/58863.pdf
- https://www.agric.wa.gov.au/news/media-releases/bacteria-key-cool-new-frost-research
- https://www.csiro.au/en/news/all/articles/2024/july/frost-tolerant-wheat
- https://www.ansc.purdue.edu/beef/articles/FrostDamagedForages.pdf
- https://youtu.be/7uohUUttlF8?si=PnpwYoYXc6X3Xvdu
- https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_G-136_25-Oct-09.pdf
