A Crash Course In Hydroponics

squ1rrely

Well-Known Member
This article will take a closer look at hydroponic systems. Hydroponics is a vastly misunderstood method of growing that will give your plants the most balanced of nutrient diets out of all the systems out there. Hydro systems are also ideal for their ability to retain both water and air, making happy, healthy roots.

Whether your an expert in the field or a novice looking to jump in head first, expect to learn a thing or two in this thorough and extensive summary of the basic hydroponic systems. From Ebb n' Flow to Drip, we'll take a closer look at their pros and cons, what you will need to make each system and how.
We'll also examine some of the more technical equipment available on the market and give a rundown on some of the best products out there and what they can do for you.

Many of you are probably already familiar with the concept of hydroponics and the systems involved. For those who aren't, hydroponics is the method of gardening in which plants are supplied with nutrients through solution in water. Gardeners have a choice of systems to accomplish this: Deep Water Culture (DWC); Drip, Ebb and Flow; Nutrient Flow Technique (NFT); Reservoir; and Wick. all of these are available as commercial units but can also be easily constructed at home.

Hydroponic systems vary in their complexity and the amount of care they require. However, the simplicity of construction or difficulty of maintenance does not necessarily infer that the crop will be larger or of higher quality.
The systems fall into one of two categories: passive and active. Passive systems, such as reservoir or wick setups, depend on the molecular action inherent in the wick or medium, sometimes referred to as capillary action, to make water available to the plant. Active systems, which include ebb n' flow, nutrient flow technique and deep water culture, use a pump to provide the plants with water and nutrients.

PASSIVE HYDROPONICS SYSTEMS

The Reservoir System

The reservoir system is by far the easiest system to set up and maintain. Plants are grown in ordinary plant containers of the chosen size. The containers are placed in a tray surrounded by walls- usually 4"-6" high.
The containers are filled with clay beads. Alternatively the bottom third of the container is filled with beads and the top portion is filled with hydroponic mix such as vermiculite- perlite, peat moss (sunshine mix #4) or even a non-hydro planting mix. The container is placed in the tray, and sits directly in a hydroponic nutrient-water solution with about 20-25% of the container immersed in the water. A container with soil 4" high should be immersed about an inch deep. A 12" tall container should be sitting in 2 1/3-3" of water. This may be the most inexpensive system and the fastest one to set up.

EQUIPMENT

  • LECA (Lightweight Expanded Clay Aggregate) (Hydroton)
  • pH test meter, pH test paper, or pH test kit.
  • Planting containers
  • Tray with walls of appropriate height
  • Hydroponic Nutrient Solution
  • EC or PPM meter
  • Submersible pump
  • Aquarium heater
  • Tray cover
  • (optional) Reservoir
  • (optional) Float valve
*optional accessories: water reservoir regulated by a float valve. The water level of this system should be maintained at a fairly stable level. As the plants grow they will use larger quantities of water so it will have to be replaced more frequently as the garden proceeds towards flowering.

Steps To Setting Up A Reservoir System

  1. Obtain enough clay beads to fill the containers.
  2. Rinse the beads in water until the pH tests close to 7, neutral.
  3. Pour the neutralized LECA (Lightweight Expanded Clay Aggregate) into appropriate sized containers.
  4. Place the containers int he tray.
  5. Water the containers from the top to get started. Make sure the planting medium and wicks are thoroughly moistened.
  6. Mix nutrient/water solution.
  7. Test the EC or PPM of the solution.
  8. Add a small submersible pump in the tray to circulate the water.
  9. If the room temperature falls, it may cool the water too much. Add an aquarium heater to the tray.
  10. Use a sheet of white/black polyethylene or other opaque cover to place over the tray. The cover keeps light from getting into the nutrient/water solution, where it would promote algae growth.

This is an excellent technique for use outdoors since the container has its own limited reservoir. The only problem is that a container with no holes can get waterlogged. To prevent this, place overflow holes at the maximum water level. If more water pours into the container, it will flow out the hole, leaving plenty of air for the roots to respire.
This technique can be adapted so that containers have internal reservoirs. The bottom 20% of the container will be filled with water. A gauge can be placed in the container to measure the water level. One method is to use a plastic tube with some holes drilled in it to allow water to enter and exit freely. Place it into the container and stick it in surrounding pebbles so it is held vertically. Take a thin wooden or plastic rod and affix a cork on the bottom of the straw using silicon glue. A bamboo stake also works will for this. Place the stake in the tube. The cork will float on top of the water, pushing the rod up to indicate water level. Mark the rod so it shows maximum desirable levels. To drain water from the pot, remove the rod and insert a small tube attached to a pump or siphon.
Another gauge can be made using a piece of transparent flexible plastic tubing. The tubing is inserted into a hole at the bottom of the container and silicon glue is used to prevent leads. The tube is attached vertically to the side of the container so it indicates its water level. To drain water, change the tube's position.
Several containers can be connected to a single reservoir regulated by a float valve, which is connected to a reservoir using tubing.
Water should be added to containers with drains sitting in trays from the top down so that any build up of nutrient salts caused by evaporation gets washed back out of the container into the tray.

The Wick System

The wick system is inexpensive to construct and easy to set up and maintain. The planting container is held above a reservoir. Both ends of braided nylon rope hang from holes in the bottom of the container into a reservoir filled with water/nutrient solution.
The principle that drives this system is capillary action, the same physics that draws water up a napkin. As the water is removed from the wick the water molecules above draw neighboring molecules towards them to maintain the electrical charge and ultimately equalize water tension. As a result, with no work on your part, the wick maintains moisture by drawing up water as needed. The wick is made from braided nylon rope. The diameter of the rope increases with the size of the container.

Container Diameter Rope Diameter
Up to 6" 1/4" rope
8-9" 3/8"
12-15" 5/8"
15"+ 3/4"-1"

An ordinary nursery container, a bucket or even a soil bag can be used. Before the container is filled with planting mix, install the wicks in the container. They should be long enough to stretch from the bottom of the reservoir through the bottom or side hole of the container, then exit the hole on the other side and run down to the bottom of the reservoir. Each container should receive two wicks at 90 degree angles.
Keeping the holes in the container small makes it difficult for roots to penetrate to the reservoir. Keeping the roots from growing down the wick into the reservoir may be a matter of convenience. However, once the roots hit the water. Both their growth and the growth of the plant spurts because the roots now have access to cheap water and nutrients.
The wick system is self-regulating; the amount of water delivered depends on the amount lost through evaporation or transpiration. More than monitoring the containers to check to see that they are moist, with the wick system the main thing is to keep your eye on the reservoir. As long as the reservoir has water, the plants are being watered.
A number of different mediums can be used as planting mixes for wick systems. Virtually any planting mix can be used since soil generally draws water. Using a planting mix has the advantage of providing the plants with a nutrient-rich base that can be supplemented using water/nutrient solution. If the medium does not seem to be drawing water and is too dry, adding 20% vermiculite to the mix will add drawing capacity.
A mix consisting half each vermiculite and perlite provides a non nutritive medium that is easy to work with, has a nice consistency and draws water well. Using vermiculite-perlite allows you to have complete control over the nutrients being supplied to the plants. Adding 10% worm castings or compost increases the microbial life and provides a substrate for them to thrive. Their symbiotic relationship with the roots increases plant vigor and growth.
Each medium has a different maximum saturation level. Beyond that point, an increase in the number of wicks does not increase the moisture level.


EQUIPMENT

  • One tray
  • Support for containers: pallet, blocks
  • Nylon rope of appropriate diameter
  • Planting containers
  • Tape or glue
  • Planting mix
  • pH test meter pH test paper or pH test kit
  • Hydroponic nutrient solution
  • EC or PPM meter
  • Submersible pump
  • Aquarium heater
  • Tray cover
  • (optional) Reservoir
  • (optional) Float valve
*optional accessories: Water reservoir regulated by a float valve. The water level of this system should be maintained at a fairly stable level. As the plants grow they will use larger quantities of water so it will have to be replaced more frequently as the garden proceeds towards flowering.

Steps To Setting Up A Wick System

  1. Install the tray in the grow space.
  2. Find a support to raise the containers 4"-6" from the bottom of the tray. Wood blocks, pallets and cement blocks work well.
  3. Measure distance from bottom of the tray through the container and back to the tray bottom. Cut nylon rope and seal ends.
  4. Place rope in containers. Tape or glue in place.
  5. Fill containers with planting medium.
  6. Place containers on supports, making sure the wicks hang down to the bottom of the tray.
  7. Water the containers from the top to get started. Make sure the planting medium and wicks are thoroughly moistened.
  8. Mix nutrient/water solution.
  9. Test the EC or PPM of the solution.
  10. Fill the tray with nutrient/water mix.
  11. Add a small submersible pump in the tray to circulate the water in the tray.
  12. If the room temperature gets too cool, it may cool the water too much. Add an aquarium heater to the tray.
  13. Using a sheet of white/black polyethylene or other opaque cover to place over the tray. The cover keeps light from getting into the nutrient/water solution, where it would promote algae growth.

ACTIVE HYDROPONIC SYSTEMS

In this section the most popular systems (DWC, Drip and Ebb n' Flow) will be covered. Keep in mind that both reservoir and wick system units can be converted into active systems with the additions of a pump, tubing, drip emitters and optional features such as an additional reservoir.
One example is a reservoir system in a 4'x4' horticultural tray that holds 8" tall containers filled with LECA (pebbles). Providing a constant stream of water/nutrient solution will increase the growth rate.
Tiny submersible pumps with tubing attached are placed in the reservoir, one for each container. Each tube sends a small steady stream of water to the top of the container, which trickles through the rocks. The roots receive plenty of oxygenated water and the spaces between the rocks provide lots of oxygen.
The redundancy of both the water stream and reservoir systems acts as a failsafe should on system fail.

Deep Water Culture (DWC)

DWC systems keep the roots bathed in oxygenated water/nutrient solution. The system consists of a submerged container that holds the plant stem in place above the water level. The roots hang down into the oxygenated water- where they have total access to water- and to the nutrients and oxygen dissolved in the water. This promotes extremely fast growth and high yields.
DWC systems require a grower's keen sensitivity to the plants. Unlike planting mixes that buffer nutrient imbalances, the DWC environment is instantly affected by changes to the water. The effects of these changes, helpful or harmful, become apparent very quickly. Experienced gardeners "read the plant" to determine its health and needs.
The common denominator of all DWC systems is a container that holds water into which the roots hang. The container holds a hydroponic planting medium such as clay pellets or rockwool cubes over the water. The reservoir water/nutrient solution is aerated using air stone bubblers, circulating water or a waterfall.
DWC systems are manufactured as stand alone containers and as sets attached to a central reservoir. Other models circulate the water utilizing tubes that connect the containers to each other. The plants are held in small containers.

EQUIPMENT

  • 3 to 5-gallon bucket (most standard buckets are 11.5" wide)
  • Hard plastic flowerpot drain tray that fits over the bucket
  • 6-8" ribbed containers to hold the planting medium
  • Air pump
  • 1/4" tubing
  • Air stone
  • Fish tank heater
  • LECA

How To Build A DWC Bucket

  1. Using a pair of clippers or saber saw, cut a hole in the drain tray large enough to let the ribbed pot fit firmly inside. Drill a hole in the tray large enough to allow 1/4" air tube to slide through.
  2. Slide the tubing through the hole in the tray. Attach an air stone to the tubing that is going into the container. Attach a small air pump to the other end of the tubing.
  3. Place a small fish tank heater set at 70 degrees inside the container.
  4. Fit the tray onto the container. Place the ribbed pot into the tray and fill with LECA
  5. Add water leaving about 4" for air. Plug in bubbler and heater.

Ebb n' Flow (Flood and Drain)

Ebb and flow are the systems most people first think of at the mention of hydroponics. The containers or rockwool cubes are held in a tray. Its depth varies depending on the containers' height. Water is periodically pumped to the tray. The planting medium holds enough moisture between irrigations to meet the needs of the plant.
Ebb and flow systems are easy to construct and their maintenance fairly carefree. They also promote vigorous growth. Ebb and flow can be used to irrigate rockwool cubes or any of the hydroponic planting mediums.
A simple manual ebb and flow system can be constructed using a try about 6" deep. Attach a flexible 1/2"-1" tube to one end of the sides at the bottom. This tube will act as the drain.
Fill 8" tall planting containers with one for the recommended hydroponic mediums and place them in the tray. Rockwool can also be used. If you are growing small plants just use 4" cubes. If the plants are to be larger, place a rockwool slab down first and set the cubes on top.
To water, hold the tube above the tray so it doesn't drip. Pour the water from the container into the tray. Then place the tube below the tray so the water drains into the container.
If you are using LECA, the first time fill the tray 4" deep with water and let it stand. If you are using coir, peat moss, a peat blend of vermiculite-perlite, fill it 3" deep; with 4" rockwool flood only to 2". Add more to maintain the level until the medium is saturated. Drain into the container using the flexible tube. This is more than the maximum amount of water/nutrient solution that will be needed each time the plants are watered.
Not as much drains back in as was poured out. Some of the water is retained by the medium. The irrigation needs of each garden will differ with planting medium, garden temperature and the size of your plants. If the medium feels moist, the plants do no require irrigation. Automating this unit is not difficult. The garden is placed above the reservoir. A tube attached to a submersible pump in the reservoir pours water into the tray above. A short cycle timer, and optionally a float valve, controls the pump. The rays drain is designed to flush slowly into the reservoir. When the pump turns on, water flows into the tray faster than it drains. The recirculating water dissolves dried salts and freshens the water in the medium. When the pump turns off the water drains back into the container from the tray.
An overflow drain is installed at the maximum water level prevents plan flooding and other accidents. If a timer rather than a float valve controls the pump's off switch, this is a necessity.

EQUIPMENT

  • Tray to hold rockwool or containers
  • Rockwool or other planting containers
  • Planting medium (if using containers), LECA, vermiculite/perlite, or peat moss mix
  • Short term timer
  • Submersible pump
  • Tubing
  • (optional) Float valve switch

Several Ebb and flow gardens can be plumbed to a central reservoir using a pump for each garden. The lost water can automatically be replaced from a reserve reservoir.
Ebb and flow system kits and components are readily available commercially. The ready-made systems are convenient, reliable and have ironed out all the kinks that a home built unit is likely to encounter. Components to make your own system are available at hardware stores and indoor garden centers.

Drip Systems

Drip irrigation works by delivering water slowly to the planting medium or soil using an emitter installed at the end of the irrigation tubing. Emitters are manufactured to deliver water at a set rate such as 1 gallon per hour (gph). The system consists of a submersible pump that delvers water from a reservoir to a flexible tube that stretches the length of the garden. Spaghetti tubing is connected to the central tubing using connectors that are punched into the main line and fit into the smaller tubing. An emitter on a spike that attaches it to the container or cube is connected to the other end.
Each container or rockwool block is serviced by its own emitter. Different sized plants can each get the appropriate amount of water by using drippers with different flow rates or several emitters. Drip rings deliver water in a circle pattern around the container rather than in one spot.They are a more efficient way of irrigating and are especially useful with LECA. Almost all hydroponic drip systems recirculate the water, so they include a reservoir that catches the drain water.
Drip emitters are used mostly in rockwool systems but they also work well with coir, vermiculite/perlite, peat moss and LECA.

EQUIPMENT(Drip System#1)

  • Table or frame with sturdy top such as 1/2" plywood
  • Corrugated plastic (available at home improvement/building supply stores)
  • Trough to catch drain water from corrugated plastic made form a rain gutter
  • Rockwool or planting containers
  • Bucket for use as temporary reservoir
  • Submersible pump used to supply water to the drip emitters
  • Spaghetti tubing from pump to garden area
  • Drip emitter
  • connectors from main line
  • Punch tool
  • Reservoir
  • Catchment bucket
  • Sump pump
  • (optional) Pressure regulator
  • (optional) Filter

Constructing A Drip System (System#1)

  1. A drip emitter system is easy to make using a sturdy table or by building a wooden frame such as two saw horses. Frames can also be made using steel shelving or PVC pimp. If you are using a frame, place a piece of 1/2" thick plywood for use as the top. Arrange a slight slope of 2.5%(1" in 40") so the water can drain easily. Place a piece of corrugated plastic over the tabletop so the water runs along the troughs to drain.
  2. Install a drainage trough along the side of the table or frame. The trough is made using plastic rain gutter. Place a holding tank at the end of the trough to catch the draining water.
  3. Place the containers or rockwool on the corrugated plastic.
  4. Set up the drip system using a temporary reservoir such as a plastic bucket.
  5. First, attach tubing to the submersible pump. Place the pump into the temporary reservoir and install the tubing across the center of the garden.
  6. Install the spaghetti tubing. First measure the length of spaghetti line required and cut the piece off the roll. Push the connector into the spaghetti tubing. Push the emitter into the other end of the line. Punch a hole in the main tubing using the tool sold with the drip equipment. Push the connector into the main tubing and place the emitter into the rockwool container.
  7. More sophisticated systems use pressure regulators and filters. These options are highly recommended.
  8. automated systems continually measure the water's pH and nutrients and make adjustments as needed. These systems are designed for greenhouses and commercial gardens rather than the small garden. Hobbyists who are computer savvy might wish to check out some articles on designing your own computer-controlled pH and nutrient delivery.
  9. To determine how large a reservoir is required, run the system with the emitters draining directly onto the plastic. Measure how much water is emitted in one minute. If possible use 100 times that amount. If for one reason or another that is too large a reservoir, use the biggest reservoir you can. The smaller the reservoir, the more maintenance is required.
  10. Place a catchment bucket at the end of the table to hold water that pours form the drainage gutter. Place a sump pump in the catchment bucket. Alternatively, devise a drain system that returns the water directly to the reservoir. The water is transferred back to the reservoir.
  11. Place the pump into the reservoir.
The system is ready to go.

EQUIPMENT(Drip System#2, Rockwool)

  • Sturdy table or frame with top
  • 5 plastic gutters, cut four gutters to 8', cut on e gutter to 4'
  • Silicon glue and/or fasteners
  • 4 caps
  • Catchment bucket
  • Sump pump
  • Reservoir
  • Submersible pump
  • Tubing
  • Spaghetti tubing
  • 33 connectors
  • 33 drip emitters
  • 32 4"x4"x4" rockwool cubes
  • Large measuring cup

Constructing A Drip System(System#2, Rockwool)

  1. This is a design for a system that is on a 4'x8' table. Usa a table frame with a sturdy top. Raise one end of the table about 3" using blocks or supports to facilitate drainage.
  2. Outline each foot of the table's 4' width. Position an 8' gutter in the middle of each marked foot. Alternatively, use eight 4' gutters that cut across the tables width.
  3. Fasten the gutters to the table using silicon glue. If that isn't sturdy enough use metal fasteners and then seal the fastening using silicon glue. Close the upper end of the gutters using caps.
  4. Attach a gutter to the table or frame to catch drainage.
  5. Place the submersible pump with tube attached into the reservoir and bring the tube up to the garden.
  6. Place 8 rockwool cubes in each gutter.
  7. Measure drip line length and cut the lines.
  8. Attach connectors and emitters to each of the 33 spaghetti drip lines and then connect them to the main line.
  9. Attach an emitter to each of the cubes.
  10. The spare emitter is placed in the system to check what's going on. Place it in a large measuring cup to get an exact reading of how much water is being emitted.

No matter which of these hydroponic systems you choose, the systems are easy to make and easy to maintain. Once you get the hang of it, you will probably want to experiment and use your ideas and experiences to develop your own system.


Enjoy:bigjoint:


This article is out of SKUNK magazine
Volume 5
Issue 4
original article by Ed Rosenthal
 
Might seem like a dumb question but is it a good idea to let the water cycle 24/7 (i.e. leave the pump on all day, every day) or should you introduce some sort of on/off cycle. I also take it that it would be better to not add enough nutes than to add too much and poison the plant rite? (i´d rather be on the safe side than make a stupid mistake. ive had minimal experience in hydro systems, its not how its generaly done where im from).
 

squ1rrely

Well-Known Member
what system are you asking about the 24hr cycle on? and yes its always better to undercut than over cut. you can always add more nutes if the plant asks for it but too much will lock it up and then your world sucks.
 

squ1rrely

Well-Known Member
I currently run DWC but when I ran ebb&flow I would feed every 4 hrs. I also started at 20% nute strength and worked from about 400 ppms starting in veg topping out at around 1400-1600 ppms before flushing.
 
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