Requirements for Growing Hydroponic Herbs:

Consideration for growing hydroponic herbs include: light, nutrients, temperature, humidity, and pH level. Once these factors are controlled, hydroponics provides a less time-consuming and superior growing medium versus conventional soil.

While propagating herbs from cuttings is a viable option, starting your herbs from seed is the most popular method for growing hydroponic herbs. Moistened propagation cubes work well for seedlings, as does a conventional soil mix. Germination typically takes 1-3 weeks. Once the seeds are of adequate size and are displaying their true leaves, the plants may be transported to your hydroponic grow system. It should be noted that seed germination is difficult when growing lavender, bay leaf, rosemary, white sage, and flavored mint (such as chocolate mint or orange mint). In these cases, a plant from a cutting (or an established plant bought from a garden center) will likely be more successful than growing from seed.

Herbs need – at the very least – 6 hours of bright, unobstructed sunlight per day. A south-facing window may provide adequate lighting for herbs. Rotating the plant to ensure all sides receive sufficient coverage is advisable. Since many plants – including herbs – thrive on up to 10-12 hours of sunlight per day, grow lights are recommended for extra supplementation, especially if your plants are not receiving the minimum natural sunlight to remain healthy. Standard fluorescent lamps may be sufficient, but their yield is less effective compared to modern LED grow lights. High intensity discharge lights [HID] are also effective – especially metal halide, which are superior for growing leafy herbs. Since grow lights with blue spectrum lighting encourage lush, bushy growth in many varieties of herbs (such as basil), grow lights with blue spectrum capability may be the best choice to grow your hydroponic herbs.

Nutrients – specifically designed for hydroponics – are another key component of growing hydroponic herbs. Combining fertilizer and water create the “nutrient solution.”  It is recommended to drain, clean and re-add a new nutrient solution to maintain optimal conditions. This process should be done at least once a month, although more frequently is encouraged. Methods for providing the nutrient solution include the Passive method (which allows you to decide when and how much nutrient solution a plant needs, without the use of pumps and timers), the Flood and Drain method (when trays and pots are flooded with the nutrient solution using a pump), a Drip System (timer-controlled method using a pump to drip nutrient solution on to the plants), the Nutrient Film Technique (NFT) and the aeroponic method.

There are various mediums to choose from when growing your herbs hydroponically. Some of the most popular include coconut coir, lightweight expanded clay aggregate (L.E.C.A), perlite, vermiculite, lava rocks, and oasis cubes, as well as sand and gravel.  These mediums act as an anchor to the plant, but do not provide the essential nutrients for the plant’s health. Thus, the grow medium you choose is of lesser importance than that of maintaining a continuous supply of nutrient solution.

Room temperatures ranging in the 70-75-degree range are ideal, along with a relative humidity level around the 40-60% range.  As with all hydroponic gardening, maintaining adequate ventilation for your herbs is important. Oscillating fans, as well as ceiling fans, work well. pH levels should be consistently checked to maintain a healthy range between 5.5 and 6.8, depending on the type of herb you are growing.

Keeping the plants bushy allows herbs to be more productive. Pinching off the tops when your plant reaches 6-12” tall will prevent them from becoming too leggy. Herbs do not require a lot of attention once your hydroponic routine is in place, and are a perfect choice for those who want to grow fresh produce all year long in a controlled indoor environment.