Spring is here, and it’s time to start thinking about growing your medicinal herbs from seed! If you’re used to starting vegetables, you’ll have a good head start, but you may find that herbs require a different approach…each with its own unique needs. Don’t worry though; I’ve got you covered. Be sure to print out your copy of the Medicinal Herb Growing Chart from the printables section in the membership area to follow along.
Understanding Herb Seed Requirements
Most seed packets or seed company websites will give you basic instructions on starting herbs. However, to really succeed, it helps to understand some key terms that often pop up. Let’s dive into those:
Light Germinating Seeds
These seeds need light to germinate. If you put these seeds on a heat mat, they will not germinate. They need direct light. You’ll want to barely press them into the surface of your seed-starting mix rather than burying them. Examples of seeds that need to be surface sown are St. John’s Wort, Chamomile, and Lemon Balm.
Heat Germinating Seeds
Some herbs love warmth to wake up. Milk Thistle, Licorice, and Tulsi, for example, love when soil temps stay around 70-75°F. A seedling heat mat works wonders here, but not grow lights. Even if your grow light produce heat, they still won’t germinate well. These seeds do best with base heat.
Scarification
For seeds with tough outer shells (think Marshmallow Root, Roselle Hibiscus, or Echinacea), scarification helps water penetrate. You can nick the seed lightly with a knife or rub it with sandpaper to speed things along. You want to rub or knick the seed just until you see the white bit called the endosperm. Then you’re ready to plant.
Cold Stratification
This simulates winter, tricking seeds into breaking dormancy. Seeds like Rose, Lavender, and Skullcap need a chill period. Moisten the seeds, pop them in a bag of damp soil, and stick them in the fridge for 4-6 weeks.
There are several different methods you can use to cold stratify. Soil blocks and damp paper towels are the most common. Whichever one you choose, pay attention to the time that the seeds need to be stratified for. While that 4-6 week timeline is typical, some need up to 12 weeks or more.
Soaking
Some larger seeds (like Fenugreek, Roselle, or Milk Thistle) benefit from a 12-24 hour soak in room temperature to hot water to soften their coat and improve germination.
How to Tell What a Seed Needs
So how do you know which approach to use if you can’t find the information? Well…just look at the seed. If you are working with tiny seeds that are very fragile, light germination is the way to go. If they’re a larger seed, heat mats are what you need. Super thick and shiny coating on that seed? Try soaking and scarifying. Is it a perennial where you live? Then start cold stratifying. At a glance…
Small, dust-like seeds (like Thyme and Oregano) usually prefer light and warmth.
Large, hard-coated seeds (think Roselle) often need scarification or soaking.
Seeds from temperate climates that naturally endure winter (like Echinacea or Lavender) usually require cold stratification.
Setting Up Your Seed Starting Area
Now that you understand how to prep your seeds, let’s talk about creating the ideal growing environment. Herbs need a bit more care than veggie seedlings.
Lights
Herbs grow best with full-spectrum grow lights. Look for lights around 6500 Kelvin (daylight spectrum) with a minimum of 2000-3000 lumens per square foot.
LED grow lights are energy-efficient and stay cool, while T5 fluorescent lights are affordable and effective but may require replacing more often.
Heat Mats
For heat-loving herbs, a seedling heat mat set to 70-75°F ensures steady, even warmth. Remember to turn it off and switch to grow lights once seeds sprout to avoid overheating.
Airflow & Humidity
Don’t forget airflow! A small fan keeps air moving, preventing damp-off disease. Herbs love humidity while germinating, but once they sprout, air circulation is key.
Growing medicinal herbs from seed takes a little more effort than vegetables — but it’s worth it. Each plant has its own personality and needs, and learning to work with them is all part of the herbalist’s journey. Make sure to reference your Medicinal Herb Growing Chart from the membership’s printable section to stay organized.
Happy planting, friends — may your seedlings be strong and your herb shelves full!
