• Holistic Farming

Shield your orchard against the invading frost

The key benefits of Silica, Potassium and Frost Guard.


The first frost doesn’t have to not mean the end of your harvest. Taking a few minutes to protect tender crops can save your crop and extend your harvest.


Crops are injured or killed by frost and freezing temperatures. More susceptible crops include tomatoes, peppers, cucumbers, squash and pumpkins, snap beans and eggplant. Other crops such as all the cabbage family crops, lettuce, spinach, chives, peas, carrots, parsnips and Jerusalem artichokes -- tolerate some frost. Brussels sprouts are better after a light frost or two, and the root crops can even while overwinter in the garden.


When frost is forecasted, concentrate your protection efforts on the warm-season crops that will be injured by cold temperatures.

Each farm is different and the ability to control frosts also depends on the infrastructure ability of each grower and farm. There are quite a few strategies growers can implement.

If the forecast is severe (below -2°C) and growers can water from overhead, then irrigating crops with water has proven successful. Run the sprinkler from the time temperatures are near freezing until the ice melts. The heat given off by the water as it freezes on the plants keeps the plants from freezing.


In my experience, if the forecast is around -2°C (even when it dips a little lower for a short period of time), I had good success by increasing Si, K and Kelp.

The protection, already starts at planting and during the entire growing season. A balanced soil nutrition program, and balanced nutrition ratios, will ensure that all nutrients are available to the plants and will increase the plants immune system.

Why is Silica so important?

In this case we look at Si in the context of frost protection. There are many other benefits Si proves to plants and various soils.

Silica acts physiologically within the plant to decrease cevapi-transpiration through the cuticle by re enforcing the cell wall. Silica is carried in the transpiration stream and is laid down at the sink where ever the stream is going. It is laid down as phytoliths and like calcium and is immobile once deposited. For this reason, a regular supply through the soil and foliar (leaf) is necessary.


Additionally, Si in plants stimulates growth, chlorophyll and metabolism and increases contents of citric acid and malic acid. Also, higher ratios of fatty acids in glycolipids and phospholipids and elevated levels of membrane lipids were noted.


Si builds plants to be more resistant towards a wide range of abiotic and biotic stresses. An increase in the resistance to aphids has also been noted. Silica also enhance cold resistance of Dendrobium moniliforme by increasing the levels of free proline, soluble sugar and soluble protein and decreasing MDA numbers.


The inclusion of Si to the tissue culture medium also enhances tolerance to low temperature. Si enhances tolerance levels of plants to various stresses by astringing activity of antioxidant enzymes, cation binding capacity of the cell walls, endogenous plant hormone level, increasing production of chitinase, glucanse, lignin, phenolics, and phytoalexins, nutrient uptake, improving strength of cell and plant, maintaining the structure of stomata and relative water content. Not every silica form is available to plants and experience shows that the best uptake of silica is in a monosilicic acid form.

Potassium – the most mobile element in plants

Excess nitrogen increases frost susceptibility new growth and should be avoided until the likelihood of frost is virtually non-existent. Nitrogen can also inhibit the uptake of potassium and should also be avoided early in the frost season for this reason.

High levels of potassium have been shown to increase frost tolerance in many crops. Any solution containing large amounts of potassium (and calcium) freezes at temperatures considerably lower.


Cold stress inhibits plant growth and development, which results in limited crop productivity. It affects plants by directly inhibiting metabolic reactions and indirectly influencing cold-induced osmotic, oxidative and other stresses.


Greater frost damage in K-deficient plants is related to water deficiency from the chilling-induced inhibition of water uptake and freezing-induced cellular dehydration. High concentrations of K protect against freezing by lowering the freezing point of the plant’s cell solution. A decrease in membrane fluidity could further affect negatively the transport of ions, water and metabolites.

The ability of plants and crops to resist frost and cold damages is in direct proportion to their ability to retain moisture within in the cell structure. Silica acts as the transport vessel (Highway) and is responsible for capillary action and can freely transport anything within the plant. Potassium allies with Si for the movement of materials throughout the plant depending where they are needed.


Cuticle and cuticular waxes protect the plant against uncontrolled water loss and transpiration. In addition, cuticle waxes are also protective against UV radiation and frost damage.


Here a few products, I have personally used, which help offer frost protection:

  • Tekno Kelp Guardian. Blend of Kelp, Seaweeds, Electrolytes, Potassium, Phosphorous and Silica. Not organic certified.

  • Foli Sil – Tri silicic acid in a monoatomic form. Organic certified.

  • Cal-Si-K – Calcium, Silica and Potassium mixed in the right ratio for immediate uptake. Organic certified.

  • Frost Guard. It assists in the survival of the plants by providing a shield in the form of a natural waxy latex which completely covers and adheres to the total plant surface on the plant including stem, leaves, buds and flowers. This prophylactic application can also be safely used on flowering crops as well.

The coating assists the plant to maintain a positive water balance in the cell structure (Si and K will keep the flow) by providing a barrier against frost and the impact of freezing conditions. The coating will not leave any residues and Frost Guard can safely be used in Organic production systems.


At the core, we can not control the frost but we can control the things we do in preparation and how we aid the plants to handle the frosty temperatures.