Growing Hydroponic Rosemary

Fun fact – Rosemary, a plant native to the hills of the Mediterranean, was once used by the ancient Greeks to improve concentration while taking exams, and there’s even evidence that a whiff of rosemary will help to improve your memory.

But rosemary’s good for more than exams.  It has a woodsy, peppery taste that happens to add a fragrant, savory flavor to almost any dish.  It’s also known to be rich in antioxidants and anti-inflammatories, which are thought to boost the immune system and improve blood circulation.

It’s important to know that while most herbs grow quite aggressively in hydroponics, Rosemary can be a little tricky.  So, plant at least 3 seeds per pod to ensure one grows, and consider using rockwool as a growing medium for this particular plant.

Hydroponic Rosemary
Difficulty Light EC Range pH Range: Time to Harvest
Intermediate 12-16hours 1.0 -1.6 5.5-6.0 4-6 weeks
Nutrient and Health Info - Rosemary is known to be rich in antioxidants and anti-inflamatories.
Tips & Tricks - Rosemary can be tricky in hydroponic systems, and is known to grow best in rockwool. Use the cut and come again harvesting method for a continuous harvest.



Rosemary can be difficult to germinate, so make sure to plant at least 3 seeds in every pod.  You can thin them out, if too many grow.  Also, rosemary is one of the few plants that you may have more success with by using rockwool for your growing medium.  If you continue to have problems growing, consider using our Seedling Starter Kit.  The paper towel method will also result in a higher rate of germination.


14-16 hours of light a day will provide these tricky herbs the energy they need to grow as quickly as possible. 

EC Range:

When growing Rosemary, keep your EC range between 1.0 – 1.6 for optimal growth.  It will grow well with basil, lettuce, parsley, peas, sage, thyme and even strawberries!

pH Range:

Rosemary prefers a pH on a slightly lower end of the spectrum.  Keep your pH between 5.5-6.0 for best results. 


Rosemary is an herb, and while its flowers can be quite beautiful, it’s not the flowers you’re after. That’s because flowering can impact the taste of your herbs, so make sure to cut off any buds you may see, unless you’re looking for something visually attractive.

Our Green Machine nutrients are the perfect blend for these stubborn herbs.  They will be less likely to cause your herbs and greens to flower, and they provide the nutrients that herbs and greens need most to grow. 


Pruning and Harvesting:

Use the cut and come again method to harvest your rosemary.  Leave at least 3 inches of plant at the base when you harvest, and more will grow back quickly.  Also, when you cut your rosemary, it begins to throw out new branches quickly, which means you’ll have even more rosemary growing the next time you harvest.

Time to Harvest:

Make sure to give rosemary time before you give up on it.  It can take 6-8 weeks before your first harvest.  And remember, if you’re having trouble, try using rockwool as your growing medium.


Rosemary may be a stubborn little herb when grown in hydroponics, but it’s a wonderful addition to herb mixes and meals.  Enjoy it knowing that it’s antioxidants and anti-inflammatory properties are good for you, and make sure to add it to your seasonings and herb mixes when you’ve grown too much to eat at any particular time.

Check Out Our Rosemary Recipes!

 Let's grow together!