Herbs are becoming increasingly popular, as is Hydroponics. Most herbs are easily adaptable to a hydroponic scenario. You do of course realize that I'm talking about edible herb - not that smokeable stuff , right ?
Now that we are on the same page - edible herbs for hydroponics. Hydroponic Herbs not only grow faster, they have been proven to have significantly higher levels of essential oils which is what produces flavor and aroma. Herbs grown in soil simply can not compare.
Some common herbs, both culinary and medicinal suitable for growing hydroponically are ...
Anise Basil Echinacea Mint Rosemary Stevia Tarragon Baby dill Sage Oregano Thyme Cilantro
This list of course is not all inclusive these are just a handful of the more popular herbs grown with hydroponics.
Related Article - Hydroponic Nutrients
Several different herbs can be grown together in a single nutrient solution so long as they have similar requirements. Vegetative leafy herbs, which are the majority of commonly grown herbs need a high nitrogen to phosphorus ratio
If you decide to use a communal nutrient solution for your herbs, The electrical conductivity [E.C.] should be maintained in the ballpark of approximately 2.5 and the pH from 5.5 - 6.0.
Some Herbs with special needs are...
Arugula will need an additional 0.4 ppm Cu [Copper] Basil - additional 80 ppm Mg [Magnesium] Chervil, Chives, Coriander / Cilantro, Lemon Balm, Rosemary, Sage, Sorrel, mint, Tarragon and Thyme can all use a Basic Nutrient Solution with no special requirements. Marjoram and Oregano - Watch phosphorus levels. A phosphorous deficiency will cause the plants to stunt somewhat and turn a darker green. Lower leaves will yellow and at times turn purplish as phosphorous is drawn from them to feed upper leaves. Dill - watch nitrogen levels as they may contribute to excessive Salt Build Up.
EC should be increased for plants receiving less than average light - short day length plants below 10 hours - EC should be no higher than 3.6. Nitrogen levels [N] should be maintained around 210 ppm. See - TDS PPM and EC in Hydroponics
Under the proper conditions the root system is less intense, it doesn't need to develop as extensively in search of nutrients and it doesn't. This allows the plant to devote the bulk of its energy to vegetative plant development as opposed to root development.
Whether you start with seedlings, seeds or cuttings the intial watering should be a half strength nutrient solution. pH around 5.8. keeping the phosphorous concentration at 80 ppm. Phosphorous is particularly important in young plants, in conventional agriculture it is sometimes used as a starter fertilizer for increasing early growth.
Once the plant is established in the case of cuttings or following germination otherwise - the nutrient solution should be bumped up to full strength.
Various hydroponic systems and growing mediums can be successfully used for hydroponic herb production.
Flood-and-drain systems with expanded clay mediums have proven to be extremely versatile for producing many common herbs.
Nutrient Film Technique [NFT] has been used very successfully in commercial operations to produce the best quality Basil.
Drip Systems using either rockwool or coco coir are successfully used as well.
Many medicinal herbs that are grown for their roots fare better in Aeroponic systems.
For a start up, a small ebb-and-flow system is best for a small hydroponic herb garden. In ebb-and-flow systems, the plants are usually held in plastic pots or oasis cubes in a flood table with a reservoir below.
A timer works a pump flooding the root systems with nutrient enriched water at regular predetermined intervals, generally every 5 - 6 hours.
The flood duration - the time frame between turning the pump on and off is usually around 15 minutes of root saturation. When the pump goes off, the water returns to the reservoir allowing for oxygenation of the roots.
Related Article - Grow Lights
A full light spectrum with ample blue spectrum light is best for most culinary herbs.
A 400 watt metal halide lamp, properly placed will cover about a 4 foot square area.
A 1000 watt one properly placed will cover about a 6 foot square area.
Keep the light at least a foot above the growing tips, but no more than a foot and a half. You will need to adjust the lamp as the plants grow.
T-5 fluorescent lamps run cooler and can be placed much closer to the plants without fear of tip burn.
Ventilation and Air Circulation
Proper air circulation is essential to plant production. Plants require Carbon Dioxide, it is what they breathe. Poor ventilation will kill plants as surely as a lack of sunlight or water will. Hydroponic ventilation systems as well as Carbon Dioxide Enrichment and control Systems are affordable and available , they clear out excessive heat and humidity and provide plants with ample carbon dioxide. They are recommended for a thriving Hydroponics Garden.
Related Article - Hydroponic Ventilation
Air temperatures of 70-75 F
Relative humidity 40-60%.
Recommendations offered on this page are generalized, there are a large array of herbs with differing requirements. Due diligence should be exercised for particular plants as some variables may not have been covered and some plants have unusual needs.