A Quick Guide to Growing Herbs Indoors - Hydroponically!

A Quick Guide to Growing Herbs Indoors - Hydroponically!

May 24, 2016

Posted by: Greg Hendrick

Filed under:growing, hydroponics

I've been growing herbs indoors with hydroponics for more than 10 years now. Why? Hydroponically grown herbs grow quickly and (to my taste) have more flavor and aroma than herbs grown in soil. 

A few other things I've learned about growing herbs indoors via hydroponics:

• Daytime temperatures of about 65°F to 70°F are preferred by herbs, although they can withstand climbs into the 70s. It's helpful if night temperatures drop at least 10°F to simulate outdoor conditions.”
• Most herbs like to be well watered but don't like constantly wet feet ... so good drainage or exposure to oxygen is important.
• Remember that plants weakened by hot, dry indoor conditions are more susceptible to spider mites, whiteflys, or aphid damage.

Here’s a list of the 8 herbs I've found grow best with hydroponics:

Cilantro

Cilantro can be used in a variety of ways but is particularly suited to Asian and Mexican dishes. Pruning back Cilantro often will help delay bolting and prolong its harvest time. I suggest planting new seeds about every 6-8 weeks to ensure good, year around production. Health benefits of Cilantro.

Chamomile

The two most commonly found types of chamomile are the German and Roman varieties. These have been used since Ancient times for their calming and anti-inflammatory properties. Health benefits of chamomile. 

Lemon Balm

Lemon Balm propagates easily and growth is rapid. Historically it has been used as a natural flavoring additive for foods, a cosmetic, an herbal tea and a highly-revered essential oil. Pick individual leaves, or bunches. If you have picked branches/bunches of them, tie them in bunches and hang them in a cool, dry location.

Marjoram

Marjoram has a milder, sweet flavor than oregano with perhaps a hint of balsam. It is said to be “the” meat herb but compliments all foods except sweets.

It thrives with full sun and grows to a compact 8 or 10 inches. Tiny white or pink clumps of flowers will form at the tips of the marjoram plant. To extend the life of the plant and encourage more leaf production, remove these buds as they form. More about majoram. 

Oregano

Oregano is great in pizza, spaghetti and marinara sauces and also complements beef or lamb stews, gravies, salads, soups, and even tomato juice!  It will germinate rapidly in Root cubes or Rapid Rooters when propagating. It grows exceptionally well indoors under high output T5 fluorescent plant lights in hydroponic systems. It’s an excellent companion plant for tomatoes and peppers and actually grows better when near basil.  Oregano is a repellent of aphids.

Mint

Mint is well-suited for hydroponic growing and was, in fact, one of the first plants to be grown hydroponically. Mint grown in water tends to have bigger, fuller foliage than land-grown mint, and is ideal in hydroponic gardens. Mint may be transplanted using cuttings.

Harvesting is easy — simply snip leaves and sprigs as needed.  To harvest larger quantities, cut stems about an inch above its growing surface.

Thyme

Thyme requires minimal fertilization when grown in a hydroponic system. It propagates well through stem cuttings and is in fact the herb which no cook should be without!  It’s an aromatic and attractive plant which likes full sun and will grow poorly in minimum light.  Thyme can be propagated easily using stem cuttings. Watch out for whitefly and spider mites though as Thyme s susceptible to them.

Basil

Basil is one of the most tasty and prolific herbs that may be grown and is extremely popular for hydroponic growing. Once mature, it can be harvested and trimmed weekly.  It prefers a pH range between 5.5 and 6.5 so fits well other herbs. Compact cultivars of basil such as “Bush” or “Spicy Globe” make fragrant and attractive houseplants without needing a lot of room. 

Watercress

Watercress is a water loving herb that can be easily grown from seed or propagated by bits of stem placed in a rooting plug or growing medium. It’s an easy cut-and-grow type of herb that’s wonderfully suited in fresh salads, soups and watercress sandwiches. Normally the thicker stems are removed and just the succulent leaves are eaten.

A few other herbs that do well hydroponically include: anise, catnip, chamomile, chervil, chives, coriander, dill, fennel, lavender, parsley, rosemary, and tarragon.

Growing Tips

Water & Nutrients for Herbs

A good quality hydroponic nutrient formulation is important. I suggest products with adequate nitrogen and a good phosphorus ratio.  Most herbs prefer low to mid electrical conductivity levels (1-1.6) and total dissolvable salt levels of between 800 and 1200 ppm (measuring total salts is a way to ensure correct nutrient levels). A slightly acidic pH between 5.5 and 6.4 is ideal. Here’s a link to a list of pH, EC, and salt levels for a number of vegetables and herbs.

Lighting

T-5 high-output fluorescent fixtures with 6500K tubes are excellent choices for a hydroponic herb garden. T-5’s run cooler than metal halide lamps and can be placed usually within 6-12 inches from the plants.  They use very little energy and are cost-effective.  

Hydroponic Systems

The Foody 8 hydroponic tower uses a growing medium such as Hydroton clay pellets to provide good anchorage and aeration and is excellent for herbs. It may be used indoors as well as outdoors.

Foody 12 vertical garden towers (indoor use only) use a siphon system which allows water in each growing pod to automatically lower every 2 minutes to pull in fresh oxygen to the roots. This feature ensures healthy plant growth and provides a good herb growing environment.