A guide to using herbs and flowers in soap recipes. Tips on which herbs and flowers are best & using fresh and dried plant material in soap
I use a lot of homegrown herbs and flowers in soap, lotions, balms, and other skincare recipes. There’s a reason for using each plant though, and choosing the right ones for the correct purpose is part of making good soap. In natural soap making, herbs and flowers are mainly used to add texture, color, and decoration. Dried rose petals decorating the tops of your bars can smell rosy and a sprinkle of poppy seeds can add exfoliation. Some flowers can tint the entire batch of soap a natural color, or add flecks of visual interest, as in the case with finely ground peppermint or lemon balm.
There are other questions to ask yourself about using plants in soapmaking. Is it skin-safe? Does it have potential therapeutic benefits? Can we use supermarket flowers? This piece helps to answer questions on how and when to use herbs and flowers in your soap recipes. There are also links to floral and herb-based soap recipes peppered throughout the text.
Best herbs for handmade soap
You can use ordinary culinary herbs to make handmade soap. Dried rosemary can create dark speckles, pureed parsley makes a vibrant green soap, and dried peppermint straight out of a teabag can be sprinkled on the tops of bars as a decoration. Though they won’t leave too much of a scent, whole herbs create interesting colors and effects in your soap batches. Some of the best dried herbs that you can use include:
The best flowers for soap making
Using flower petals in soap can be a little tricky. Some of them turn brown if you try to stir them into your soap batter. Others might not be suitable for skincare recipes so please research a plant and its flower before using it. If a flower is edible, then it’s a safe bet for using in making handmade soap. If it is not, or is known to be toxic if eaten, then don’t use it in skincare.
When using flower petals, you have the option to use them as a puree to tint your soap, as in the case of goldenrod. You can also sprinkle dried flowers onto the tops of your soap and in some cases, such as in calendula, you can stir petals whole into the batter. Very few flower petals will keep their vibrant color in soap but calendula is one of them.
Be aware though, that using fresh or dried flowers and herbs in or to decorate soap can be problematic in humid climates. The moisture in the air gets into the plant material and causes it to discolor or mold. I don’t live in a humid climate and have never had this happen to me. I have heard of soapmakers in Florida and India encountering it though.
Some of the best flowers to use in your homemade soap recipes include:
Adding dried herbs to soap
Dried herbs are easy to use in soap making. You can use them to infuse into your soaping oils or water, or you can sprinkle them into your soap batter or on the tops of your bars. Most dried herbs added whole will look dark in your finished bars. Think little dark brown and black speckles. Parsley flakes can hold their vibrant green a bit better and sage keeps a dark green tint.
For a speckled effect, use dried herbs that are finely pulsed — think of the consistency of ground coffee. Add about 1/2 to 1 teaspoon of dried herbs to every pound (454g) of soap in your recipe. Sprinkle it on your soap at ‘Trace’ and then stir it in. Pure, dried herbs can bleed a little into your soap as it cures, leaving a warm halo effect around each speckle.
Whole dried herb leaves can also be used to decorate the tops. Theoretically, they can be used in the soap batter too but be aware that they will re-hydrate after you start using the soap. Imagine full-sized, and potentially slimy, peppermint leaves in your soap. Dried herbs can also be infused into oil or water and then used in your soap recipes. The scent probably won’t hold but infusing herbs give color and possibly therapeutic value.
Adding fresh herbs to soap
Adding fresh plant material to soap can cause issues including your soap growing mold. This happens when microorganisms begin growing in the water still inside the plant material and it occurs more often with whole plant material added fresh. When a herb is pureed, you can add it in small quantities to your soap batter at ‘Trace’. As the water content evaporates out of your soap during the curing process, so does the water content of the herb. Large pieces of fresh or cooked plant material, such as leaves, petals, vegetables, or fruit, can spoil your soap.
However, some culinary herbs are relatively dry and can be added fresh. Rosemary, lavender leaves, and thyme can be chopped up and added fresh at 1-2 tsp per pound of oils in your soap recipe. I’d advise caution when adding wetter herbs in this manner though. Unless pureed, wet herbs such as basil and parsley can leave your soap bars mucky and spoiled.
Using dried flowers in soap
Adding flowers to any natural soap recipe can transform an ordinary bar into a botanical treasure. Take for example my lavender & honey soap recipe. The bars in themselves are great for your skin and beautifully scented but it’s the dried lavender on top that makes them special.
Decorating the tops of soap batches with dried flowers is very popular in the soap making lessons I give on the Isle of Man. Many dried flowers such as cornflowers, chamomile, and rose petals will keep their color (for several months at least) if sprinkled on the tops of soap. The key tip is to not insulate the soap after since this extra heat can turn the flower petals brown. Another tip to keep flowers from turning brown is to add them after the soap is fully cured. Spray the soap with witch hazel or isopropyl alcohol and scatter the flower petals on top. They’ll stick to the soap after it’s dry.
Mixing flowers into soap
Mixing dried flowers into soap batter will often turn the flower petals brown. This is sadly the case for flowers such as rose petals and lavender but an exception to the rule is calendula. It holds its sunny yellow or orange color indefinitely. Instead of using flower petals whole, some people also use dried flowers to make a tea that is used in place of the water in a soap recipe. Most of the time the color of flower petal infusions won’t hold up in soap recipes but sometimes it does, as in the case of goldenrod. Floral teas usually don’t have much scent, and you cannot rely on them to add scent to your soap.
Some dried flowers can be infused into a carrier oil to naturally color your soap. Calendula flowers come in both yellow and orange and I find the orange petals infuse beautifully into olive pomace oil and other light-colored oils. Infusing St Johns Wort flowers into light-colored carrier oil tints it into a deep red, which is useful in creating pink to coral colored soap. When using infused colored oil, you replace part or all of an un-infused oil, such as olive oil, with your infusion.
Using fresh flowers in soap
You treat fresh flowers much the same as you would wet plant material in soap — with caution. Large pieces of fresh plant material can grow bacteria and mold if they don’t dry out quickly enough. If you’re going to use fresh flowers in soap, you should opt for pureeing them or using them in a water infusion. With a water infusion, a tea, you strain the petals out or you pour them in with your lye. Both the lye and the action of the immersion blender will pulverize the petals into small pieces.
Many flower petals will turn your soap brown if you use them in a pureed form. Exceptions include calendula, rudbeckia (black-eyed Susan), goldenrod, and daffodils. These golden petaled flowers will all tint your soap buttery hues of yellow to orange. To make a puree, blend your fresh flower petals with enough water to make a thick soup. Use this puree to replace up to half of the water content of your soap recipe. You can also use fresh flowers in a water infusion, basically a tea.
Growing your own herbs and flowers
The herbs and flowers that you use to make handmade soap can come from a farmer’s market, a herbalist’s shop, or your own garden. Please be careful with flowers from supermarkets though, as many roses and other bouquet flowers are sprayed with pesticides and fungicides. Homegrown is best, and I think that using herbs and flowers from your garden in soap adds a special story to your handmade products. Just imagine soap decorated with your own rose petals or cornflowers!
You can grow some skincare plants in pots and containers but others will prefer growing in a border. On Lovely Greens, you can find a lot of tips for growing herbs and flowers for skincare recipes but one of the best resources for growing useful plants is my book, A Woman’s Garden Grow Beautiful Plants and Make Useful Things. Skincare plants feature in chapter four, but you’ll also learn about plants to grow for the kitchen, home cleaning, natural dyeing, and herbal medicine.
On the website, begin with growing and harvest lavender, then move on to learn more about calendula. It’s probably the most versatile skin herb that you can grow and I have a specialized ebook detailing how to use calendula in skincare.