Imagine plucking a ripe, round tomato right from the stem and sinking your teeth into its juicy flesh. There’s nothing tastier than a fresh tomato, right? Now imagine it’s December and there’s snow outside. Fresh tomatoes, from the vine, in December? Oh, and you live in New England? “Impossible!” you say? Not so. With a small indoor grow-room and a hydroponic system, you can have fresh vegetables all year. Not familiar with hydroponics? It’s a soil-less method of growing plants using light, water, and supplemental nutrients. There are a few different ways to grow hydroponically, but here we will look at the three most popular systems: Deep Water Culture (DWC), Nutrient Film Technique (NFT) and Ebb & Flow Technique (EFT).
Deep Water Culture, also known as Direct Water Culture or the Reservoir Method, is a hydroponic method of growing plants by means of suspending the plant roots in nutrient-rich oxygenated water. Traditional methods of DWC use plastic buckets with the plant contained in a plastic net pot suspended from the center of the lid and the roots suspended in the nutrient solution. An aquarium air pump, or air stone, constantly bubbles in the nutrient solution, oxygenating the water, keeping the plant’s roots from drowning. DWC can be used two ways: in self-contained systems using individual buckets or with a system of inter-connected buckets using a separate water reservoir to re-circulate the water and nutrients throughout the bucket system.
Image credit hydroponicsnutrients.co
The advantage to using a single bucket system is that if any diseases present themselves, they will affect just the plant or plants associated with that single bucket. The disadvantage is that it is extremely labor-intensive to regularly lift each bucket’s lid to check on water, nutrient levels and pH, especially with larger plants such as tomatoes. Conversely, using the re-circulating, inter-connected system allows you to adjust the ph, water and nutrient levels in the main reservoir only, thus limiting the labor involved. However, should a disease present within the system, it will affect all the plants in the system since the water is circulating throughout each bucket. Caught early enough, such an outbreak can be controlled and reversed, which is why daily inspection of your plants and equipment is crucial.
Stevia growing in a storage tub.
With its simple design, DWC is the easiest of the three main methods of growing hydroponically to be successful with for the home grower. Plants tend to grow much faster because nutrients and high amounts of oxygen are continuously being fed directly to the roots.
Nutrient Film Technique (NFT) uses a thin layer, or “film”, of nutrient solution flowing over the roots of the plants. All of the plant’s nutrient needs are met through the air and water solution washed through the plant’s root system. No growing medium is used, except for what is used for allowing the seed to germinate. The plants grow in channels, which are normally flat-bottomed runways cut into a slight “V” shape and positioned on a slope. The nutrient solution is fed at one end, following the slope, and drained back into the reservoir tank to be re-circulated. The root mat develops partly in the shallow stream of re-circulating solution and partly above it. This is an important balance to maintain, since the roots need adequate oxygen to survive.
Image credit ecocityhydroponics.com
This system uses a reduced volume of nutrient solution compared to other systems, and the solution may be more easily heated during the winter months to obtain optimal temperatures for growth, or cooled during hot summers to avoid bolting.
A creative use of NFT to grow lettuces at Disney’s Epcot greenhouse.
While this method seems at first blush to be the best of all hydroponic systems, it must be monitored closely. The pitch and rate of the nutrient flow must be adjusted (usually between 1-3%) to get the correct combination. Also, it is the most susceptible of all of the systems to power outages. Systems should not be too long in length (more than 15 feet), or the plants at the end of the line, so to speak, will not grow as well as the other plants placed in the beginning or middle of the line. Plants that work best with this type of system are smaller plants such as herbs, romaine lettuce, mustard greens, vegetative plants, kale, and oriental vegetables.
Ebb & Flow Technique, also known as the Flood and Drain System, works by temporarily flooding a grow tray full of plants with nutrient solution, soaking the plant roots for a while and then draining the solution back into a separate reservoir. This is normally done with a submerged pump on a timer set to repeat the process a number of times within a 24-hour period. The flooding simulates typical top-watering techniques. Once the roots are watered, or “flooded”, the water drains back into the reservoir chamber, leaving the roots to sit in the moistened grow medium until the next flood. The trick is to determine what the optimum number of floods should be in a 24-hour period. You need enough waterings to keep the roots from ever drying out, but not so much to promote root rot or inhibit oxygen uptake. The frequency of your timed floods will depend on many factors, including the type and size of your plants.
Image credit steadygrowpro.com
One disadvantage to this grow method is that your plants must all require the same amount of watering and nutrient type and strength. You may find that you will need to set up may flood tables in order to grow a variety of plants. A distinct advantage, however, is that plants can be manually watered during a power outage to avoid roots drying out before power can be restored.
When choosing a soil-less grow medium for this method, you’ll find there are many to choose from: clay pellets, rock wool, perlite, and lava chips are just some of the many choices available. Home-growers interested in this option should research which growing medium would be best suited for the plants they decide to grow.
Creating an Indoor Grow Room
Creating an indoor grow room can be as simple or as complicated as you allow and the costs will fluctuate accordingly. If you don’t have a greenhouse to operate from, a basement or spare room will work just fine. The room should not be too large where you cannot control temperature. Any enclosed space with electricity that is close to a water source will work fine. Be sure to think about ergonomics when laying out the room. Give yourself enough space for maintaining equipment and checking on plants as well as harvesting. The room should be clean and pets should not be allowed in the room. Most pets have access to the outdoors and carry mites and other enemies of a grow room. Remember that the room does not provide natural protection from such pests and diseases like that which can be provided in an outdoor garden. Hygiene is of the utmost importance. Remove shoes and garments that have been recently worn outdoors before entering the room. Your diligence will pay off if you can avoid a breakout of spider mites, aphids, or other pests and diseases in your room.
Lighting and Temperature
Regardless of the hydroponic technique you choose, if you are growing indoors, you will need to provide lighting. Plants will require different lighting requirements depending on their stage of growth, but as a general rule, all plants require at least six hours of darkness for each 24-hour period. In the younger, vegetative stage, plants require a longer light cycle than that of the flowering or fruiting stage. T-5 lights are a good choice since they have a high output but don’t waste a ton of energy. Plants can be placed closer to T-5 lights without fear of them being burned by extreme heat. T-5s provide full spectrum lighting which encourages both vegetative and blooming growth. Other lights only provide blue (vegetative) or red (blooming) light.
Temperature can be controlled a number of ways and should mimic the temperature that the plants thrive in while in an outdoor environment. Ventilation and air circulation should be provided as well, to keep humidity under control. By far, the equipment you choose for your grow room will be the most expensive purchases of your entire indoor growing experience. Start small and make sure you enjoy growing indoors before investing in top-of-the-line, expensive equipment.
Advantages and Disadvantages of Growing Hydroponically
Regardless of which method you choose to use, there are advantages and disadvantages to growing hydroponically, as opposed to growing outdoors in soil.
Roots receive nutrients directly – resulting in faster growth
Can be grown in smaller areas – no need for roots to “spread out” to find water
Growers have more control over the growing environment
There is the opportunity for year-round harvesting
No weeds to pull!
Hydroponics uses considerable less water than other methods of growing
Wildlife damage, insect infestation and disease are greatly reduced/eliminated
Less labor is needed than traditional growing methods – hydroponic systems can be almost fully automated
There can be more up-front and ongoing costs associated with growing hydroponically (i.e., equipment, lighting, electricity, etc.)
Systems require ongoing maintenance
Systems are vulnerable to power outages and may require generators if long-term power outages are likely.
Not all plants can be grown hydroponically. Growers must do their research and choose their plants accordingly.
Growing hydroponically has become a passion for many people – a passion some swear by for increased vegetable yields and quality. You be the judge. Do your research and get the facts.
One word of caution: there is a whole industry of medical marijuana growers that use hydroponics to grow their product. Because of this, some people associate hydroponics with marijuana growing. If you’re not licensed for this sort of thing or it’s not your area of interest, be aware that you may run into marijuana growing information while researching hydroponics. Just be specific with your keyword searches in Google and you will find exactly what you’re looking for. Here’s to tomatoes in December and happy gardening!
10 Tips for Successfully Growing Hydroponically
1. Customize your growing environment to your plants’ needs. The correct lighting and room temperature are essential to the health of your plants. If you are growing a mix of vegetables, more than one grow room may be necessary – one for heat-loving plants and one room for plants that prefer cooler temperatures.
2. The temperature of your nutrient solution is crucial. Try to keep your nutrient solution at around 65°F for high levels of dissolved oxygen and optimum nutrient uptake.
3. Plants grown indoors under lights will take up water at a greater rate than they take up nutrient. Regularly top up your tanks with water or 50% strength nutrient solution. Keep your top up nutrient solution in a separate barrel rather than using water straight from the tap (this allows the chlorine in the water to evaporate before use).
4. Maintain the pH of your nutrient solution at around 5.8 – 6.2. Check regularly as it can rise as the plants feed. It’s perfectly fine to turn your pumps off for half an hour while you adjust your nutrient solution’s pH and strength.
5. Drain your nutrient solution and replace with a fresh batch every 7 to 10 days for optimum yields. Obviously bigger tanks can get away with less frequent changes.
6. Thoroughly clean your tanks in between crops with a soap solution and rinse thoroughly.
7. An effort to limit the light allowed in to the container must be made. Wherever there is light and nutrients, algae will grow. Algae eat the nutrients you are feeding your plants, and when pieces of algae die they attract fungus gnats. Fungus gnats are a whole other problem!
8. Use a half strength nutrient solution to start your plants off, moving to two thirds to full dosage rate (as detailed on the bottle) after the first nutrient solution change (about 7 – 10 days after planting). This reduces the chances of “burning” or shocking your plants.
9. When plants start fruiting, all but the smallest of plants will need additional support.
10. Finally, don’t crowd your plants! They will grow incredibly fast – give them plenty of room to grow.