In Astro-Herbalism and traditional Alchemical processes, the placement of the planets is crucial to the medicine making process. Knowing the optimal time to harvest each plant ensures that the plant’s vital force is at its fullest potential.
There are several factors at play here, and it is nearly impossible to have all the stars line up perfectly. (Pun intended). For example, say we wanted to harvest Dandelion roots. Roots are typically harvested in the fall or early spring, when the plant's vital force is concentrated in the roots and not the aerial parts. Dandelion is ruled by Jupiter. Ideally we want to harvest Dandelion when Jupiter’s energy is at its peak. Jupiter rules Sagittarius and Pisces, so these seasons are when Jupiter is strongest.
Each year Sagittarius season falls around November 20th to December 20th, and Pisces season falls around February 20th to March 20th. In a lot of areas in the Northern Hemisphere, the ground is frozen during these seasons making it very difficult to dig roots. Scorpio season is actually the ideal time to harvest roots, around October 20th to November 20th. During Scorpio season (ruled by Mars and Pluto) the plants are returning to the Underworld to sleep, concentrating all their vital force in their roots in the process. This is when root medicine is at its peak.
So if the Jupiter ruled seasons are not ideal to harvest our Jupiter-ruled roots, how do we still ensure that our Dandelion roots are imbued with Jupiter’s energy? This is when we look at the days and hours.
Each day of the week is ruled by a planet:
Monday = Moon-day
Tuesday = Mars-day (named for Tyr in Norse Mythology, the Norse God of War)
Wednesday = Mercury-day (Named for Odin in Norse Mythology, also known as Woden god of learning, poetry and magic)
Thursday = Jupiter-day (Named for Thor, god of thunder, lightning and the sky in Norse Mythology)
Friday = Venus-day (Named for Freya, or Fregg, goddess of love, beauty and fertility in Norse mythology)
Saturday = Saturn-day
Sunday = Sun-day
Each planet also has its own hours during the day. Typically in a 24 hour period, a planet will rule two separate hours. If we cannot harvest our plant during the planet’s strongest season, next up would be the planet’s day, and if possible the planet’s hour. So that would mean that we would want to harvest our Dandelion root on a Thursday, during the Jupiter hour, ideally in Scorpio season.
However, plants tend to do what they want. They are not always ready to harvest when the timing is perfect. Sometimes they need to be harvested a couple days before the ideal day or sometimes after. Maybe the strongest hour is in the middle of the night or maybe the weather is less than ideal. Or maybe, for whatever reason, we just can’t get out that day.
Then there’s the whole issue of wildcrafting. It’s easy to harvest on the appropriate day and hour, and even season, if you are harvesting from your garden. Wildcrafting takes a lot of planning if you want to harness the planetary energy in a wildcrafted plant. You would need to head out on the right day and be there at the right time to harvest on the strongest hour. Planning ahead would require knowledge of the plant you are seeking and where exactly it will be growing. You will need to know what day you are going and when the appropriate hour will be. It is very difficult to make all these requirements come together. So we do our best. Maybe we wildcraft our Dandelion simply on a Thursday, ignoring the hour. Or maybe we just harvest when we can, realizing that Jupiter will be in Dandelion anyways.
Now the next question is, how do I know when the correct planetary hour is? There are a couple different ways to calculate this. You can divide the day into 7 planetary hours which have a length of 3 hours and 26 minutes each. That means the first planetary hour is from midnite until 3:26am. The second hour is where we start assigning rulers, meaning the second planetary hour, from 3:26am to 6:52am will be ruled by the planet who rules that day. The next planets fall into line in order. For example, if you are doing calculations for a Friday, Venus will be the one to kick off the second planetary hour.
An easier way is to simply divide the day into its 24 hours with the planet of the day ruling the hour starting at 6am.
The easiest way, and by far my favourite way, is to download an app! Yes there are apps that calculate planetary hours. There are a few out there, but the one I like to use is simply called Planetary Hours. It gives both the day and the hours.
It is important to remember, that just like with people, the planetary ruler of a plant is not the only actor at play. All the planets are present in a plant (just like people). It is the interplay of all the planetary energies together that determine the individual characteristics of a given plant (and person). Different plants may contain many different medicines in them, and each part of the plant that holds that medicine may need to be harvested under a different influence.
Let’s go back to Dandelion. Dandelion as a whole is ruled by Jupiter. Jupiter rules the liver. Dandelion root is a liver medicine, making Jupiter energy the best energy to harvest Dandelion roots under, but what if we want to harvest the leaves? The leaves are a kidney medicine. The kidneys are ruled by Venus meaning that to harvest the leaves it would be beneficial to do it under Venus’s influence.
We can use Nettles as another example. Nettles is an amazingly complex plant that is ruled by Mars due to it’s sharp, serrated leaves and the inflammation they leave behind, and also its affinity for the blood, which is ruled by Mars. If we want to harvest Nettle leaves we are best to do it under Mars’s influence. Nettles begin to pop up during Aries season. Mars also rules Aries. This means the perfect time to harvest Nettle leaves would be in the middle of Aries season, on a Tuesday at the Mars hour. The seeds of Nettle, however, are a kidney medicine. Once again, the kidneys are under Venus. Nettle seeds are normally ready to harvest in Libra season and Libra is a Venus ruled sign. This means the ideal time to harvest Nettle seeds is in the middle of Libra season, on a Friday at the Venus hour. To make Nettles even more complex, the root is a prostate medicine! The prostate is under Scorpio’s rulership and Mars happens to also rule Scorpio, which is perfect because Scorpio season is our root medicine season. So now, the best time to harvest Nettle root is during Scorpio season, on a Tuesday at the Mars hour!
If this all seems super complex, that’s because it is, but it’s not so complex that it is impossible to learn. You are learning a new framework to view the world with, a new language to use to talk about herbal medicine.
Step one is to learn which areas of the body each planet and sign rule. Second is to determine the planetary ruler of your plants. This is definitely the hardest part. There are pretty much no modern sources of plant-planetary rulership out there. Culpeper and Cornell are the best known sources, and Culpeper lived several centuries ago! Also different sources may list different rulerships. I have seen Mugwort listed under both the Moon and Venus. This doesn’t mean either of them are wrong. I believe this means that the plant has a secondary ruler, and possibly a third and fourth...it all depends on what the medicine is for. Also, not all plants will have assigned rulers. The plants that are in Culpeper and Cornell’s works are old world European plants, the plants they would have worked with while they were alive. A lot of North American plants have not been assigned a rulership. This is where you get to do the leg work! Look at what the plant does in the body. What are it’s affinities and energetics. What does your gut tell you? Once you figure out the ruler of the plant, the rest of it is easy peasy!
So, go get yourself some Culpeper and Cornell, and download a planetary hours app and get to work! Having an astrological framework to work with while harvesting brings a whole new magic to herbal medicine making.