How to Harvest, Dry, and Cure Flowers From Your Greenhouse

Written by Megan Allen and supported by Mark Seibert of Sturdi-Built Greenhouse Manufacturing

This guide takes you through the essential steps to effectively preserve your blooms. When you master this process, you can enjoy your greenhouse-grown flowers in various ways throughout the year.  Keeping a journal of your experiences will help you perfect your craft.

Preparing for Harvest

The maturity stage of flowers varies from one plant to another. For example, you can harvest most flowers just before they are fully open, and they will continue to open after cutting, particularly in a vase. Here’s three of many exceptions:

  1. Lilies should be cut when the first bud starts to open and color shows.
  2. Roses are best to harvest roses when they are slightly more open, just before they have fully unfurled.
  3. Timing a cannabis harvest ensures the highest levels of cannabinoids and terpenes to maintain the quality of the product despite using different rosin presses.

Recognizing the right time to harvest ensures optimal quality and longevity of your blooms.

Once you have determined the optimal time to harvest your flowers, gather your tools and prepare your workspace. Essential tools for harvesting include sharp, clean garden shears or scissors, which help make a clean cut that prevents damage to the vascular system and promotes better water uptake. Commercial moisture meters are another tool for checking the moisture content in cannabis buds, checking flower moisture content before processing, and monitoring moisture loss or moisture gain in plants during the drying and curing process.

Gloves are advisable to protect your hands from thorns or rough stems and for skin allergies. It’s good to have a bucket of water handy to put your cut flowers immediately after harvesting, to keep the flowers hydrated right from the start.

Harvesting Techniques

With your garden shears or scissors in hand that are clean and sharp, make angled cuts on the stem.  For roses, cut just below any thorn above any leave to encourage new growth. Using this technique prevents plant damage and promotes longevity. The angled cut increases the surface area for water uptake, a critical factor for post-cut survival.

Harvest flowers early in the morning when the water content is highest, which reduces wilting. Immediately after cutting, place the stems in a bucket of clean water to prevent air embolisms that can block water absorption.

As you move the bucket of cut flowers to your drying area, if necessary, control the environmental conditions during transport; avoid placing flowers in direct sunlight or overly hot conditions because it can speed up dehydration and deterioration.

Drying Your Flowers

There are different drying methods, each with advantages and disadvantages. As such, choose one that can preserve the shape, color, and texture depending on the type of flowers you are drying and the desired outcome. The following are the most common methods:

Air Drying

Air drying works best with flowers that naturally retain color and shape when dried, such as lavender, roses, and hydrangeas. The primary advantage of air drying is its ease; it requires minimal equipment and is energy-efficient. However, the downside is that it can take several weeks, and the results may vary depending on humidity and air circulation.  If you’re creating a dried flower bouquet, use the hanging method to air-dry flowers. Air drying takes longer, but the results are beautiful.  The most suitable flowers for this method are Carnation, Chrysanthemum, etc.

Start by removing your flowers from the water when they are at peak bloom and then remove the leaves from their stems. Trim your stems to your desired length before drying them. Using twine, tie the stems at the bottom or use a rubber band to hang them upside down in a dry place.  Grouping is a good idea. For example, five stems of large-head flowers and 10 stems per group of smaller-head flowers.  Avoid drying in direct sunlight to slow down fading of the flower colors.  This method of air-drying offers a straight stem, versus leaving the stems to dry in a vase, which causes the blooms to droop.

Silica Gel Drying

Using silica gel involves burying the flowers in a granular substance that draws out moisture. This method is faster than air drying, taking only a few days to a week, and it preserves the vibrant colors and intricate details exceptionally well. You can get silica gel from most craft stores, online retailers, or specialty shops catering to horticulture and preservation needs. The drawbacks are the cost of silica gel, which may be prohibitive for large batches, and the need for careful handling to avoid damaging the flowers during the process.


Dehydrators offer a controlled environment with consistent heat and airflow, resulting in quick and uniform drying. This method is excellent for thicker flowers, such as peonies or roses, that might not dry well in air. However, dehydrators can be expensive, and heat can sometimes cause flowers to lose their natural color and become brittle.

Cut the flowers to remove leaves; cut the stem very short. Spread flowers on the dehydrator trays in a single layer without overlapping to make sure flowers dry equally. Place in a dehydrator and dry at 135°F for 4-12 hours depending on the size of your flower; rotate the trays often to dry flowers evenly.

Unless sun drying is possible where you live, the energy cost of dehydrating foods at home is higher than for canning and, in some cases, more expensive than freezing. Electric dehydrators produce a better-quality dried product than any other method of drying.

Curing Flowers

While drying removes most of the moisture from the flowers, curing fine-tunes this process, allowing them to acclimate to the ambient humidity gradually, thus stabilizing their form and minimizing the risk of mold growth or brittleness. This gentle and controlled exposure to air helps maintain the shape and color, making them more durable for long-term display or use in crafts, such as floral arrangements, wreath making, or even as standalone pieces of natural art.

Here is the step-by-step process:

Step 1: Arrange the Flowers

Lay dried flowers in a single layer on a flat surface, such as a drying rack or mesh screen, for optimal air circulation. Ensure the flowers are not overlapping, as this can lead to uneven curing and potential moisture retention, which might cause mold.

Avoid using paper towels or newspapers, as these materials can retain moisture and may cause the flowers to develop mold or decay. Additionally, paper products can stick to the flowers, potentially damaging their delicate petals or trapping unwanted debris.

Step 2: Set Up the Curing Environment

Store your blooms in a cool and dry location. Select a location without direct sunlight, with a temperature between 60- and 70-degrees Fahrenheit (15.6 and 21.1 degrees Celsius).

Step 3: Monitor Humidity and Temperature

A hygrometer measures the humidity and temperature of the air. To limit moisture reabsorption, the humidity should be maintained around 40-50%. Adjustments might be necessary depending on initial readings and changes in weather conditions.

Step 4: Daily Checks

During the first few days, check the flowers daily to ensure no mold or mildew is developing and the flowers are not absorbing moisture. Moisture meters are a useful for checking flower moisture and monitoring moisture loss or moisture gain in plants during the drying and curing process.  If you discover mold or mildew on any of the flowers, address the issue promptly to prevent further spread and damage. Depending on the severity of the mold or mildew, you may need to trim affected areas, isolate and discard severely affected flowers, or adjust drying conditions to prevent recurrence.

Step 5: Final Assessment - Are They Done Yet?

After about one to two weeks, check the condition of the flowers. They should feel dry, and the petals and stems should be rigid but not brittle. If the flowers meet these conditions, the curing process is complete.  If the petals are brittle, you have waited too long.  Next time, check the flowers sooner or more often.  Record any key learnings in your growing journal.

Storing Your Dried and Cured Flowers

For storage, many container options are suitable, depending on the type and size of the flowers. Airtight containers are ideal for smaller, more delicate flowers to protect them from dust and moisture. These can be glass containers for a visually appealing display. Larger bouquets or branches may need acid-free boxes to maintain shape without crushing the petals.

Ensure the storage environment is cool, dry and out of direct sunlight to prevent moisture reabsorption. You can add silica gel packets to absorb any residual moisture. Silica gel is often the preferred choice due to its high moisture absorption capacity.

However, if silica gel is not available, other effective alternatives include dry rice, which is readily accessible and absorbs moisture well, and salt (calcium chloride), also known for its ability to manage higher levels of humidity.

Inspect your stored flowers every few months for signs of moisture or mold. If any flowers show these signs, remove them immediately to prevent the spread to other flowers.


Figure 6 Image by Monfocus from Pixabay

Mastering the techniques of harvesting, drying and curing greenhouse-grown flowers is a rewarding endeavor that enhances the beauty and longevity of your blooms. Starting with careful harvesting at the optimal time ensures the flowers retain their vibrant colors and structural integrity.

Employ the appropriate drying method, then cure them to stabilize the moisture content. You can experiment with different types of flowers and preservation methods, as each variety may respond differently to the processes discussed.

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