Growing hydroponically

NPK Technology · June 27, 2014

Hey everyone,

We wrote this for our website blog, we thought it might be nice to share it with all of you. Hope you enjoy

Imagine the first juicy bite of a perfectly ripened, locally grown, fresh summer tomato. Now, imagine foregoing those grainy, artificially ripened tomatoes from the grocery store and enjoying the unmatched goodness of homegrown tomatoes all year round. You can make that dream a reality by growing hydroponic tomatoes right in your own home. Growing tomatoes hydroponically allows you to monitor and control the lighting, temperature, and nutrients that the plants receive, thus controlling the flavor, sweetness, and nutritional value produced by the plants. Even the extreme novice can successfully produce fresh, succulent tomatoes with a little background information and technique tips.

Starting Hydroponic Tomato Seeds
It is highly recommended to begin with seeds rather than plants as plants can be contaminated with disease or pests. Rockwool starter cubes and standard dome nursery trays are a great start. Soak the rockwool cubes in water with a pH of 4.5. Plant the seeds. Keep trays covered and in a damp setting that remains consistently between 20 and 25 degrees Celsius (68°-77°F) until the plants start to sprout. As soon as vegetation shows, the seedlings should be moved to a light source for a minimum of 12 hours each day. Make sure that the roots never gain light exposure as this can stunt growth and even kill the roots completely. When leaves have sprouted and the roots are visible at the bottom of the rockwool cubes, the plants can move into their new hydroponic home.

Types of Hydroponic Systems For Tomatoes
Choosing the right hydroponic grow system depends on space availability, the type of tomato, and the size of the plants. Deep water culture (DWC) is most often used for the cultivation of only a few plants as it is fairly tedious to maintain. Generally, in a DWC system, one plant is grown per pot. A clay pebble growing medium is used. The water and nutrient mixture must start out at a high enough level to saturate the clay. After the root system is established, the water level should be lowered so that most of the roots are well into the water, but so that a few are in the empty space between the water level and the container. An air stone is used to aerate and mix the nutrient-rich water and should always run 24 hours a day. The pH in this type of system tends to naturally fluctuate, so it should continuously monitored.

If you have not had much experience with hydroponics, the nutrient film technique (NFT) may be the setup that you most recognize. Consisting of only a grow tray or tube, a nutrient reservoir, an air pump and stone, and a nutrient pump, it needs no timer and no growing medium. The nutrient pump carries the solution to the grow tube. The plants are usually contained in baskets and the roots dangle directly into the solution. The solution flows down the tube and back into the continuously aerated reservoir. The roots will dry out very quickly if the flow of nutrients is broken, so this type of system leaves the plants extremely susceptible to pump malfunctions or power outages.

For larger plant systems and commercial growing, a drip irrigation system is often used. In this type of system, a nutrient solution is pumped through an automated system that drips the solution onto the plants and re-circulates it. Plants and starter cubes are placed directly into individual pots that are each connected to the nutrient reservoir and haydite rocks are used to sufficiently aerate roots in a confined space.

Aeroponics is perhaps the most sophisticated technique. In an aeroponic system, the root systems are suspended in the air above the nutrient solution. The nutrient pump is controlled by a timer that periodically mists the roots with the solution. The timing and proper functioning of the pump is critical. There is little room for error using this method of hydroponics as clogged sprayers and pump failures can ruin a crop very quickly. It should also be noted that, in my knowledge, there are no large scale commercially grown aeroponic tomatoes.

Hydroponic Tomato Nutrient Requirements
The water quality and the nutrient solution are the key factors to successful hydroponic tomato cultivation. The pH of the water should remain between 5.0 and 7.0 at all times for optimal nutrient absorption. The pH of the nutrient solution should be between 5.5 and 6.0. The electrical conductivity of the water should be less than 0.5 mS/cm.
Pruning & Staking Tomatoes
The concentration of the nutrient solution must be adjusted at various stages throughout the growth cycle. The essential nutrients are divided into macro and micro elements. The macro elements (required at higher concentrations) are calcium, carbon, hydrogen, magnesium, nitrogen, oxygen, phosphorus, potassium, and sulfur. The micro elements are boron, chlorine, copper, iron, manganese, and molybdenum. Essential concentrations are measured in parts per million (ppm) or milligrams per liter (mg/L). Tomatoes require a relatively low nitrogen level compared to leaf crops and root crops. The required micro element levels for tomatoes are as follows: boron 0.44, chlorine 0.85, copper 0.05, iron 2.5, manganese 0.62, molybdenum 0.06, and zinc 0.09 ppm. The necessary concentration of macro elements changes after the plants reach about 24 inches tall and the fruit reaches about 1 to 1.5 cm in diameter. More nitrogen is needed in summer months or during times of higher light exposure, and more potassium is needed in the fall and winter months.

Nutrient Deficiencies

Nutrient deficiencies can cause a whole host of unwanted effects on the plants and adversely affect the crop’s fruit yield. pH levels that are too high result in hindered nutrient absorption. pH levels that are too low allow excessive absorption. Maintaining optimal lighting and temperature ranges create the best environment for healthy, high-yield plants. Some disorders may not show any visible signs right away or at all, so it is very important to ensure that your nutrient solution is properly maintained. Deficiencies can cause varying degrees of problems from delayed maturity, small fruit, curling and yellowed leaves to limited fruit yields and aborted flowers.

Lighting Requirements For Hydroponic Tomatoes
Light is the most important growth influencing factor. During the vegetative stage, plants produce a healthy supply of leafy vegetation that will later go on to feed and support the product yielded during their flowering stage. When starting a tomato seed, you can supply 24 hour light through to early vegetative stage. During the vegetative state, mature tomato plants thrive on 16 to 18 of direct light per day and eight hours of darkness for respiration.

LED grow lights are becoming increasingly popular to grow hydroponic tomatoes. They emit a powerful mixed spectrum of light that uses 1/3rd to 1/2 the energy compared to HID lighting. They also produce a minimal amount of heat, so they can safely be placed as close as within 30 cm of the plants. Plants respond more vigorously to the clean, cool, intense light emitted by LED grow lights, experiencing increased growth rates over HID so be sure to keep an eye on your nutrients.

Pruning and Staking Hydroponic Tomato Plants
Maintaining the architectural structure of the plants as they grow larger and begin to produce higher fruit yields keeps the plants strong and optimally feeding the fruit produced. You can use plastic twine to encourage a straight vertical growing path and to support the structure as it produces heavy fruit. Lateral side shoots and suckers should be removed. Gently break off suckers with your hands to avoid damaging or contaminating the plant. If the top of the plant dies, leave one strong lateral shoot to grow into the new leading shoot. Remove yellowed leaves at the main stem to avoid risk of disease and infection.

Patience and practice will ultimately lead you to a successful hydroponic tomato crop. Carefully balancing nutrients, aeration, pH levels, temperature, and lighting and misting schedules is a delicate process that takes some getting used to in order to get the greatest flavor, size, and quantity out of your produce. As you gain experience with recognizing potential issues and adjusting settings, you will no doubt learn to produce beautiful, delicious, vine ripened tomatoes year round.

Hope you enjoyed,

NPK

Bevans18 · December 6, 2014

I've been growing Heirloom and Better boy tomatoes since 22Oct (about 6 weeks). Plants are about 20 inches tall with about a 1.5 - 2 foot canopy. I've been trying to manage the light through DLI measurements that try to achieve a greater than 20 mole/m2/day light schedule. I've been using a Spectrum Light Scout for these measurements. My question is regarding the type of lighting you would suggest at the different stages of growth. I currently have a variable ballast that can give 400W, 600W or 1000W. I used a T5 light to grow seedlings for first 3 weeks, HPS 400W setting for weeks 3-5 and just switched to HPS 600W last week while I was trying to get the DLI into a 12 hour time frame. I have a 1000W HPS bulb as well as a 1000W Metal Halide bulb to allow for flexible lighting schedules with the ballast as I learned about different DLI measurements. My plan was to switch to metal halide lamp in week 8 to support the fruiting stage. Does this seem like a good lighting strategy? What type of lamps have you used before? Thanks for your thoughts.

NPK Technology · December 6, 2014

Hi Bevans 18,

Firstly, don't use a metal Halide for the flowering stage. It has too much of the blue spectrum and not enough red in it. The plants like and need plenty of red towards the end. Up to now, you have used a perfect lighting and you seem 'on-the-ball' as you know about DLI and measuring light intensity. Just finish off on HPS and you should find you'll get a good harvest (depending on other areas such as environment, nutrients, CO2 etc.)

We have used T5's, CFL's, HPS, MH and now LED's. All have their pro's and cons and all are good for certain environments. Show us some pictures would be great!

Good luck harvesting =)

NPK Technology

Cole_Robbie · December 6, 2014

For weeks 3-5, that 400 should definitely be halide and not hps. You can grow nice fruit with a halide all the way through, but the yield just won't be as high as if you finished with an HPS bulb.

Speaking of bulbs, make sure you buy quality. You want a grow bulb with a balanced spectrum. And they don't last forever, halides degrade more quickly than hps.

Especially with the big bulbs, cooling is a serious issue. It's also a safety issue with halide bulbs. HPS bulbs tend to pop internally, but when a halide gets too hot it will explode and send several-thousand-degree glass everywhere, hot enough to ignite whatever it touches or seriously maim a person.

Hermitian · December 6, 2014

Quote:

Originally Posted by NPK Technology

... The plants like and need plenty of red towards the end. ...

IMO this is hype to sell more bulbs, especially to the novice cannabis crowd. In actual studies with statistical controls the best results on fruit and bud crops are achieved at a color temperature of 6400-6500 Kelvin near 70 Watts per square foot at 1 meter throughout. An exception to the energy density are cucurbits which due to the larger leaf size can achieve their maximum performance near 55 W/sq.ft.

Bevans18 · December 10, 2014

Hello all, Thanks for the lighting comments. I remember reading some Univ. study saying that HPS in the first part of the tomato growth cycle was advantageous and Metal Halide was better in the flowering stage. Maybe I mixed these two in the sequence. Regardless I think your recommendation now is to finish off with the HPS and that will give adequate light for fruiting stage.

The plants are about 22-24" tall now with the following environmental conditions.
I have a 4'x4' room lined with white plastic where I built using 2'x4's a structure to hold the Sunlight Supply Inc, Dominator XXXL 6 " duct- SunSystem Light Deflector 2ftx3ft with an Ultra Sun 1000W HPS bulb
Temperature - I've been pretty successful at keeping temperature during lighting hours at 75-80F with a temperature controlled duct fan at top of area entry where heat rises. Outside garden area conditions are cooler temperatures at 62-28F in surrounding room.
CO2 - With the temperature controlled duct fan I am assuming that there is adequate airflow in the area to provide air exchange.
Humidity - since it is winter here in Massachusetts, it's fairly dry but I've been able to keep the humidity between 20-40%, but no higher.
Nutrients - I've used Clonex Cloning solution for the first two weeks, Floraduo A/B and GH RapidStart for next 4 weeks, TDS currently about 1000-1200ppm, pH 5.5-6.5.

I've noticed a little curl on the leaves. I don't think its any disease but this is one of my first indoor experiences. Please comment on pictures(first time attaching - hope they come through).
Thanks!

June 27, 2014	#1
NPK Technology Tomatovillian™ Join Date: Jun 2014 Location: Liverpool Posts: 8	Growing hydroponically Hey everyone, We wrote this for our website blog, we thought it might be nice to share it with all of you. Hope you enjoy Imagine the first juicy bite of a perfectly ripened, locally grown, fresh summer tomato. Now, imagine foregoing those grainy, artificially ripened tomatoes from the grocery store and enjoying the unmatched goodness of homegrown tomatoes all year round. You can make that dream a reality by growing hydroponic tomatoes right in your own home. Growing tomatoes hydroponically allows you to monitor and control the lighting, temperature, and nutrients that the plants receive, thus controlling the flavor, sweetness, and nutritional value produced by the plants. Even the extreme novice can successfully produce fresh, succulent tomatoes with a little background information and technique tips. Starting Hydroponic Tomato Seeds It is highly recommended to begin with seeds rather than plants as plants can be contaminated with disease or pests. Rockwool starter cubes and standard dome nursery trays are a great start. Soak the rockwool cubes in water with a pH of 4.5. Plant the seeds. Keep trays covered and in a damp setting that remains consistently between 20 and 25 degrees Celsius (68°-77°F) until the plants start to sprout. As soon as vegetation shows, the seedlings should be moved to a light source for a minimum of 12 hours each day. Make sure that the roots never gain light exposure as this can stunt growth and even kill the roots completely. When leaves have sprouted and the roots are visible at the bottom of the rockwool cubes, the plants can move into their new hydroponic home. Types of Hydroponic Systems For Tomatoes Choosing the right hydroponic grow system depends on space availability, the type of tomato, and the size of the plants. Deep water culture (DWC) is most often used for the cultivation of only a few plants as it is fairly tedious to maintain. Generally, in a DWC system, one plant is grown per pot. A clay pebble growing medium is used. The water and nutrient mixture must start out at a high enough level to saturate the clay. After the root system is established, the water level should be lowered so that most of the roots are well into the water, but so that a few are in the empty space between the water level and the container. An air stone is used to aerate and mix the nutrient-rich water and should always run 24 hours a day. The pH in this type of system tends to naturally fluctuate, so it should continuously monitored. If you have not had much experience with hydroponics, the nutrient film technique (NFT) may be the setup that you most recognize. Consisting of only a grow tray or tube, a nutrient reservoir, an air pump and stone, and a nutrient pump, it needs no timer and no growing medium. The nutrient pump carries the solution to the grow tube. The plants are usually contained in baskets and the roots dangle directly into the solution. The solution flows down the tube and back into the continuously aerated reservoir. The roots will dry out very quickly if the flow of nutrients is broken, so this type of system leaves the plants extremely susceptible to pump malfunctions or power outages. For larger plant systems and commercial growing, a drip irrigation system is often used. In this type of system, a nutrient solution is pumped through an automated system that drips the solution onto the plants and re-circulates it. Plants and starter cubes are placed directly into individual pots that are each connected to the nutrient reservoir and haydite rocks are used to sufficiently aerate roots in a confined space. Aeroponics is perhaps the most sophisticated technique. In an aeroponic system, the root systems are suspended in the air above the nutrient solution. The nutrient pump is controlled by a timer that periodically mists the roots with the solution. The timing and proper functioning of the pump is critical. There is little room for error using this method of hydroponics as clogged sprayers and pump failures can ruin a crop very quickly. It should also be noted that, in my knowledge, there are no large scale commercially grown aeroponic tomatoes. Hydroponic Tomato Nutrient Requirements The water quality and the nutrient solution are the key factors to successful hydroponic tomato cultivation. The pH of the water should remain between 5.0 and 7.0 at all times for optimal nutrient absorption. The pH of the nutrient solution should be between 5.5 and 6.0. The electrical conductivity of the water should be less than 0.5 mS/cm. Pruning & Staking Tomatoes The concentration of the nutrient solution must be adjusted at various stages throughout the growth cycle. The essential nutrients are divided into macro and micro elements. The macro elements (required at higher concentrations) are calcium, carbon, hydrogen, magnesium, nitrogen, oxygen, phosphorus, potassium, and sulfur. The micro elements are boron, chlorine, copper, iron, manganese, and molybdenum. Essential concentrations are measured in parts per million (ppm) or milligrams per liter (mg/L). Tomatoes require a relatively low nitrogen level compared to leaf crops and root crops. The required micro element levels for tomatoes are as follows: boron 0.44, chlorine 0.85, copper 0.05, iron 2.5, manganese 0.62, molybdenum 0.06, and zinc 0.09 ppm. The necessary concentration of macro elements changes after the plants reach about 24 inches tall and the fruit reaches about 1 to 1.5 cm in diameter. More nitrogen is needed in summer months or during times of higher light exposure, and more potassium is needed in the fall and winter months. Nutrient Deficiencies Nutrient deficiencies can cause a whole host of unwanted effects on the plants and adversely affect the crop’s fruit yield. pH levels that are too high result in hindered nutrient absorption. pH levels that are too low allow excessive absorption. Maintaining optimal lighting and temperature ranges create the best environment for healthy, high-yield plants. Some disorders may not show any visible signs right away or at all, so it is very important to ensure that your nutrient solution is properly maintained. Deficiencies can cause varying degrees of problems from delayed maturity, small fruit, curling and yellowed leaves to limited fruit yields and aborted flowers. Lighting Requirements For Hydroponic Tomatoes Light is the most important growth influencing factor. During the vegetative stage, plants produce a healthy supply of leafy vegetation that will later go on to feed and support the product yielded during their flowering stage. When starting a tomato seed, you can supply 24 hour light through to early vegetative stage. During the vegetative state, mature tomato plants thrive on 16 to 18 of direct light per day and eight hours of darkness for respiration. LED grow lights are becoming increasingly popular to grow hydroponic tomatoes. They emit a powerful mixed spectrum of light that uses 1/3rd to 1/2 the energy compared to HID lighting. They also produce a minimal amount of heat, so they can safely be placed as close as within 30 cm of the plants. Plants respond more vigorously to the clean, cool, intense light emitted by LED grow lights, experiencing increased growth rates over HID so be sure to keep an eye on your nutrients. Pruning and Staking Hydroponic Tomato Plants Maintaining the architectural structure of the plants as they grow larger and begin to produce higher fruit yields keeps the plants strong and optimally feeding the fruit produced. You can use plastic twine to encourage a straight vertical growing path and to support the structure as it produces heavy fruit. Lateral side shoots and suckers should be removed. Gently break off suckers with your hands to avoid damaging or contaminating the plant. If the top of the plant dies, leave one strong lateral shoot to grow into the new leading shoot. Remove yellowed leaves at the main stem to avoid risk of disease and infection. Patience and practice will ultimately lead you to a successful hydroponic tomato crop. Carefully balancing nutrients, aeration, pH levels, temperature, and lighting and misting schedules is a delicate process that takes some getting used to in order to get the greatest flavor, size, and quantity out of your produce. As you gain experience with recognizing potential issues and adjusting settings, you will no doubt learn to produce beautiful, delicious, vine ripened tomatoes year round. Hope you enjoyed, NPK

December 6, 2014	#2
Bevans18 Tomatovillian™ Join Date: Jun 2014 Location: Massachusetts Posts: 8	I've been growing Heirloom and Better boy tomatoes since 22Oct (about 6 weeks). Plants are about 20 inches tall with about a 1.5 - 2 foot canopy. I've been trying to manage the light through DLI measurements that try to achieve a greater than 20 mole/m2/day light schedule. I've been using a Spectrum Light Scout for these measurements. My question is regarding the type of lighting you would suggest at the different stages of growth. I currently have a variable ballast that can give 400W, 600W or 1000W. I used a T5 light to grow seedlings for first 3 weeks, HPS 400W setting for weeks 3-5 and just switched to HPS 600W last week while I was trying to get the DLI into a 12 hour time frame. I have a 1000W HPS bulb as well as a 1000W Metal Halide bulb to allow for flexible lighting schedules with the ballast as I learned about different DLI measurements. My plan was to switch to metal halide lamp in week 8 to support the fruiting stage. Does this seem like a good lighting strategy? What type of lamps have you used before? Thanks for your thoughts. Last edited by Bevans18; December 6, 2014 at 04:31 AM.

December 6, 2014	#4
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	For weeks 3-5, that 400 should definitely be halide and not hps. You can grow nice fruit with a halide all the way through, but the yield just won't be as high as if you finished with an HPS bulb. Speaking of bulbs, make sure you buy quality. You want a grow bulb with a balanced spectrum. And they don't last forever, halides degrade more quickly than hps. Especially with the big bulbs, cooling is a serious issue. It's also a safety issue with halide bulbs. HPS bulbs tend to pop internally, but when a halide gets too hot it will explode and send several-thousand-degree glass everywhere, hot enough to ignite whatever it touches or seriously maim a person.