SunBurn - An ever-increasing problem

Produce in the field is extremely susceptible to sun damage. An estimated 20 - 40% of produce in orchards and fields may be damaged as a result of sunburn, and the problem continues to rise with global warming. It is the radiative heat from the sun that is the cause, not a high ambient temperature.

Damage usually occurs during very hot days when the energy of sunlight can cause sunburn on the sun-exposed surface of the fruit especially when there is no breeze to remove heat from around the plants. The heating effect of sunlight combined with the damaging effects of ultra-violet (UV) light are the main causes of sunburn in fruits.

The most susceptible growth stages are early fruit development and just prior to harvest, because as the fruit matures and fills, its increased weight causes an outward shift of the fruit in the canopy, exposing new areas of the fruit to the sun. The sudden movement of fruit from shade to direct sunlight can cause sunburn, even at lower temperatures.

Sun damaged fruits get a bleached/yellow or brown appearance not suitable for the fresh market, leaving it only available for processing and causing significant economic loss.

With SunCalâ„¢, a newly engineered thin film of benign sunshield, growers can reduce sun damage and heat stress, and therefore reduce product losses, improve manifest and increase returns.

SunCal - The best sunburn protection

SunCal is a food grade nano particle sized calcium carbonate, which is available in an easy to use liquid formulation. SunCal is sprayed directly on the produce throughout the growing season to:

  • Build a protective coating that blocks harmful UV and IR light (heat), without restricting photosynthesis and fruit coloring
  • Provide a valuable source of Calcium to the crop.
  • Generate an extra source of soluble Calcium Citrate and CO2

While remaining a:

  • A liquid formulation easy to store, mix and spray
  • A Formula compatible with most other crop protection products and fertilizer
  • A tool to reduce overall water usage
  • An easy product to clean off while still rain fast


1. Unique submicron particle sizes

Most currently available products for sun protection commonly use china clay/ kaolin (Aluminium Silicate), which although cheap, is abrasive, difficult to remove from the fruits and does not provide any source of Calcium nutrition.

SunCal is made of nanosized particles of Calcium Carbonate (CaCO3), a natural chalk source much less abrasive and hard than clay, allowing the product to:

  • Stay in suspension during spraying to give a uniform coat of protection on the crop.
  • Be less abrasive to the spraying equipment than alternative products.
  • Be less abrasive to the produce due to smaller rounded particles capable of tissue penetration to provide a source of calcium usable by the crop.

2. Blocks harmful UVB Rays

Spraying SunCal on the crops will visibly create a white protective layer that will reflect the light, blocking the most harmful UV rays and providing an effective sunscreen for the plant, while leaving room to the wavelengths needed for natural fruit colour development and photosynthesis required for good crop growth.

3. Provides a valuable source of calcium

At every application of SunCal you are also providing a valuable source of Calcium to the crop leaf material.

Because SunCal is sprayed on the leaf, it also contains humectants and surfactants in its formula to give about 30 minutes to the crop to absorb some calcium while the product is drying.

Most of the particles in SunCal being nano-sized, some will have the capability to enter the leaf tissue through the spaces between the cells (Interstitial spaces).

This provides the crop with valuable tissue Calcium with the capacity to reduce stress and improve robustness, fully replacing another source of Calcium and therefore saving extra costs for the farmer. Typically high-Calcium fruit exhibits longer shelf-life.

4. A potential source of extra Calcium citrate and CO2

When SunCal is washed off directly from the tree with a weak acid like citric acid it releases C02 and calcium Citrate.

The Calcium citrate will instantly be absorbed by the produce and will contribute to extended shelf life of fresh, whole and minimally processed, fruits and vegetables.

The CO2 will settle close to the ground and be absorbed over night increasing photosynthesis and spurring plant growth.

5. An easy to use liquid formulation

Where other products notoriously have short shelf life due to settling if stored badly, SunCal is a Liquid formulation that is easy to store, mix and spray:

  • The proprietary formulation has built-in stickers, humectants and spreaders, that will not settle out in the spray tank and thus provide a consistent concentration of product throughout the entire tank. As what you put in goes out through the nozzles at a constant dispersion rate, it means no sludge in the bottom of the spray tank.
  • SunCal is compatible with most other crop protection products as well as foliar fertilisers and bio-stimulants.
  • SunCal can also aid in reducing water usage as it reduces the crop water stress index, preventing excessive transpiration rates leading to water loss with its physical barrier effect.
  • The product an be applied by manual crop spraying and with aircraft or drones.

6. An easy product to wash off

Last but not least, where most anti-sun burn protection product are very hard to wash off the produce, SunCal offers easy and beneficial cleaning ways both straight off the tree and from harvested fruits while remaining rain fast in up to 40 mm of rain.

  • A simple mildly-acidified water BELOW pH 4.0 in the packing house washing process
  • 25 kg of citric acid per 1000L of water applied with the same sprayer as was used to apply the SunCal