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Flower Preservation: Drying Flowers with Silica Gel

Flower Preservation: Drying Flowers with Silica Gel

Posted by Bawantha Perera

Drying flowers is a great way to keep their natural beauty long after they've been picked. Among the many methods available, using silica gel crystals is one of the best for keeping the vibrant colors and delicate shapes of flowers. In this guide, we'll go over everything you need to know about drying flowers with silica gel crystals.

What is Silica Gel and the Difference Between Silica, Silica Gel/Crystals, & Sand (Powder)

Silica gel and silica crystals are both used as desiccants, but they have distinct differences. Silica sand, used for drying flowers, is typically made by grinding silica gel or a blend of gel and crystals and other additives.

Silica gel is a solid form of silicon dioxide (SiO2), which is more granular and hard rather than a gel in its traditional sense. It is amorphous and porous, known for its harmless nature (except for blue silica gel), often used in food products. The gel contains millions of tiny pores that can adsorb and retain moisture. Silica gel is a desiccant capable of holding 30 to 40% of its weight in water.

Understanding Flower Drying

What is Flower Drying? Flower drying is the process of removing moisture from freshly cut flowers to preserve their shape, color, and beauty. This method allows flowers to be used decoratively long after they would naturally wilt.

Methods of Flower Drying There are several methods for drying flowers, including air drying, pressing, microwave drying, and using desiccants like silica gel or silica sand.

Uses of Dried Flowers Dried flowers can be used in many ways, from preserving wedding bouquets and making resin art pieces to creating potpourri and floral arrangements. They add a natural touch to any space or art project.

Why Do Fresh Flowers Change Color After Drying?

Fresh flowers change color during drying due to moisture loss and chemical changes in their pigments. The drying process alters their cellular structure and can cause oxidation, leading to changes in color. Here are the main reasons: 

  1. Moisture Removal: Fresh flowers have a lot of water, which makes their petals vibrant and clear. When using something like silica gel to absorb this moisture, the petals lose their translucency, leading to a duller or darker look.
  2. Chemical Changes: The drying process can change the pigments in the flowers, like chlorophyll, anthocyanins, and carotenoids. For example, anthocyanins, which give red, purple, and blue flowers their color, can change hue or fade when dried.
  3. Light and Air Exposure: During drying, flowers can be exposed to light and air, causing oxidation. This can lead to browning or fading of colors. Silica gel helps reduce air exposure, but some oxidation can still happen.
  4. Structural Changes: Moisture loss causes the petals' cell structure to collapse, changing how light interacts with the surface and affecting color. 

Silica Gel Beads/Crystals vs. Silica Sand: Which is Better?

Silica gel beads or crystals are preferred over silica sand for drying flowers because they absorb moisture slowly and evenly, creating a controlled drying environment that better preserves the flower's shape and color. In contrast, silica powder absorbs moisture rapidly, which can potentially lead to deformation and changes in the flower's color. Interestingly, while silica gel beads/crystals worked well for most flowers, silica sand (powder) demonstrated advantages for miniature, small, and delicate flowers. Its finer texture allowed it to penetrate small cavities without harming delicate petals, making it a preferred choice for these more fragile specimens.

At Artland, we have explored various methods for drying/preserve flowers using different types of silica gel, desiccants, microwave, sundry, air dry (hung upside down), using an electric food dehydrator, and unconventional materials such as activated carbon, calcium chloride, borax, sodium chloride (common salt), glycerine, baking soda (sodium bicarbonate), uncooked dry raw rice, clay, activated alumina and bio clay or cat litter. Our experiments also included silica gel in forms such as beads, crystals (blue, white, orange, milk white, fumed), and silica sand/powder blends. Each method exhibited unique artistic qualities, influencing how different types of flowers responded to drying techniques.

Among the tested methods, drying flowers with silica gel (beads, crystals, or powder) proved notably faster and less messy than alternatives. It also offered greater control over the drying process, despite the higher cost involved. Our findings consistently showed that silica gel beads or crystals, particularly in white, orange, or blue varieties, outperformed silica sand in terms of preserving colors and minimizing damage, which is crucial for flowers intended for resin art. These conclusions aligned with insights from international sources such as Just Resin, although individual outcomes varied based on material quality, environmental conditions, and personal preferences.

Update (Sep 2024): We also discovered that activated alumina works well, similar to silica gel beads, though it dries flowers more slowly. This slower drying helps retain the colors better for certain flower types.

Improper Use of Silica Gel Improper use of silica gel crystals or sand can lead to significant color change. Common mistakes include using too much silica gel to speed up the drying process, not sealing the container properly, or drying flowers that are not fresh. 

Preparation for Optimal Results: Choose fresh flowers at their peak bloom. Make sure they are dry and free from dew, water, and insects.

Materials and Supplies Needed for Drying Flowers with Silica Gel:

  • Fresh flowers
  • Silica gel beads or silica sand
  • Airtight plastic or metal container
  • Pruners or scissors
  • Gloves and mask (recommended)

Caution: After drying flowers, do not reuse the container for food preparation, as silica gel may absorb pesticides from the flowers.

How to Dry Flowers Using Blue or White Silica Gel Crystals (Beads or Chunks)

Step-by-Step Drying Process:

  1. Preparation: Trim excess leaves and stems from the flowers. Choose a container large enough to hold the flowers without crowding.
  2. Layering: Pour a 1-2 inch layer of silica gel crystals into the bottom of the container. Place the flowers upright on the crystals, making sure they are not touching each other.
  3. Covering: Gently sprinkle more silica gel crystals around and over the flowers until they are completely covered. Make sure the petals are supported to maintain their shape.
  4. Sealing: Seal the container with an airtight lid and place it in a cool, dry location. Let the flowers sit for about 2-5 days (flower buds may take additional time), depending on their size and moisture content.
  5. Checking: Check the flowers periodically for dryness. When they feel crisp to the touch, carefully remove them from the silica gel.

How to Dry Flowers Using Silica Sand (Powdered Silica)

Step-by-Step Drying Process

  1. Trim Flowers: Use scissors or pruning shears to remove excess leaves and trim the stems to your desired length.
  2. Container: Choose a container large enough to hold the flowers without crowding. 
  3. Layering: Pour a 1-2 inch layer of silica sand into the bottom of the airtight container. 
  4. Place Flowers: Arrange the flowers upright on top of the silica sand layer. Make sure the flowers are not touching each other to avoid sticking together.
  5. Covering: Gently sprinkle more silica sand around and over the flowers until they are completely covered. For delicate petals, use a small paintbrush to help distribute the sand without damaging the flowers. 
  6. Sealing: Close the container with an airtight lid to prevent moisture from entering.
  7. Drying Time: After 1-5 days, check the flowers for dryness. Smaller flowers may dry faster, while larger ones and flower buds may take longer.
  8. Test for Dryness: Gently touch the petals. If they feel crisp and dry, the flowers are ready. If not, reseal the container and check again in a few days.
  9. Removing Flowers: Once dry, carefully remove the flowers from the silica sand. Use a small paintbrush to gently remove any excess silica sand from the petals.
  10. Storage and Display: Store dried flowers in a cool, dry place away from direct sunlight to prevent fading.

Tips and Tricks to Minimize Color Change

  • Timing: Harvest flowers for drying when they are at their peak bloom.
  • Handling: Be gentle when handling flowers to avoid damaging delicate petals.
  • Temperature: Keep a consistent temperature during the drying process to prevent uneven drying and color loss.
  • Use Silica Crystals for Color Preservation: Silica gel crystals provide a more controlled drying environment, helping preserve flower colors better than powder.
  • Storage: Store dried flowers in a cool, dry place away from direct sunlight to maintain their color.

Silica Gel Safety Precautions:

Silica gel desiccant is non-toxic, non-flammable, and stable under normal conditions of use. Ingesting silica gel is generally not harmful, as it is primarily used to absorb moisture in enclosed spaces.

Blue silica gel, containing cobalt chloride as a moisture indicator, should not be used in direct contact with items intended for consumption, such as food or pharmaceuticals.

However, accidental ingestion may cause some side effects:

  • Silica sand/powder can potentially affect the respiratory system.
  • Silica gel beads are a choking hazard.
  • Dry eyes and throat irritation.
  • Aggravation of dry mucous membranes and nasal passages.
  • Upset stomach or gastrointestinal discomfort.

By following these steps and tips, you can successfully dry flowers using silica gel crystals while preserving their natural colors and shapes. Whether you're making a centerpiece, decorating your home, or creating resin art, dried flowers add a timeless beauty that captures the essence of nature.

Preserving flowers with silica gel crystals not only extends their lifespan but also allows you to enjoy their beauty in various creative projects. Enjoy the art of flower drying and find the many ways to use dried flowers in your artistic projects!

Warning, Notice and Disclaimer

WARNING: Do not dry edible flowers for consumption using flower drying silica, as it may contain toxic boron.

Notice: We update this regularly to keep it current and accurate.

Disclaimer: We (Artland) provide this information in good faith, aiming for accuracy. However, we cannot guarantee specific results. Users should do their own research and consult professionals as needed.

References/Sources: Wikipedia about Silica Gel | White Silica (MSDS)