Extreme Outdoor Hydroponic Systems
The systems in this chapter are designed to deal with all predators, domestic and wild. These predators can cause problems for novices and experienced gardeners alike. Since animals such as dogs, cougars, and bears like to bite on tubing (and other man-made objects), it is advised to make systems that they cannot tamper with. These systems can be of value to a homesteader or a country farmer that is exposed to such predators.
We have already discussed fertilizing earlier in this chapter. Any commercial product used at the recommended rate works. Now we will look at hydroponic feeding in greater detail. A grower should know how to feed hydroponically in order to grow a successful crop in a hydroponic system.
Rule #1
A grower should try to grow with a local medium. The natural surroundings may contain materials like fir bark, granitic sand (.6mm to 2mm; 1/16-inch in size), granitic gravel (1.5mm to 2.0cm; less than 3/4 in size), hemlock sawdust, peat moss, or dolomite sand (which shifts pH and contains calcium and magnesium).
It makes no sense spending a fortune on materials and transportation to a farm site, if quality hydroponic mediums are there in the first place. Most commercial hydroponic farms use materials that are available nearby.
After noting what materials are available nearby, the grower should consider what type of system to build in order to make use of the growing medium.
Although there are an abundance of hydroponic mediums out there, another factor to consider is water schedule. Some mediums; like a combination of peat moss and pin shavings is cheap, hold air and moisture, while one with 100% pine shavings would dry out quickly.
For example, a grower in a controlled environment such as a greenhouse, may wish to implement a top-feeding system using a medium that allows the roots to get sufficient oxygen and nutrition, such as clay, sawdust, fir bark, perlite, or perlite / sand.
On the other hand, a grower in a wild country setting may rather use local granitic sand opposed to local granitic gravel. If sand is used, a one-way system can be implemented easily if plants are fed intermittently with a solar-powered pump. Sand that is fed at the proper rate will not have too much runoff waste, and therefore a recirculating system is not necessary. But if gravel is used, the solution will drain more rapidly, thus a recovery system must be used or a giant reservoir must be utilized so that plants don’t dry up.
Rule #2
A grower should use a system that will give a reasonable yield with easy maintenance.
For example, if a grower decides to set up a commercial farm on property where many wild animals live, such as bears, deer, cougars, etc., then a hydroponic system where all the feeding materials are buried underground may be necessary in order to keep the plants alive. Many snoopy animals may examine a man-made obstacle, yet they tend not to make a serious mess of a non-food source. Tubing exposed above the ground will probably get chewed on, thus leaving holes in unwanted areas which can lead to solution going to the wrong places.
Bottom-Feeding
A good system that can be used anywhere would be one in which large beds or trenches are built, 1 to 2 feet wide and up to 3 feet deep, depending on the crop and the time of planting. The beds or trenches should be lined with 1 to 2 sheets of 6ml black plastic, followed by PVC pipe buried at the bottom; next, top up the beds or trench with the growing medium. Beds or trenches should have a small slope so that solution drains down the bottom. A 1-inch slope for every 4 to 8 feet works, allowing the solution to drain freely out of one end, or to drain back into the reservoir and be recirculated. Holes should be made in the bottom of the PVC pipe for solution to escape into the growing medium so that bottom-feeding is possible. Some PVC drain pipe comes with holes in the pipe, thus saving a step of work. The diameter of the pipe depends on the flow rate going through the pipe. 1 to 3-inch pipe will do the trick.
It is possible to use smaller diameter PVC pipe, or polybutylene tubing. In this case a grower may want to put more than one piece of pipe in each trench, or place them close together in a bed.
All the PVC should be end capped so that solution is forced through the holes.
The flow rate being pumped through the pipe will be the more important factor in determining spacing than the diameter of the pipe. And, PVC under 1-inch is often substantially cheaper than the larger sizes. Also, as PVC increases in diameter, so does its thickness, therefore weight is another factor to consider, especially if moving the PVC for long distances is part of the program.
If predators are not a problem, plants can be top-fed instead of bottom-fed. Top-feedings helps against salts building up, as opposed to bottom-feeding methods. Bottom-fed plants should get flushed periodically unless a good percentage of the fertilizing formula is organic, with a low salt count.
A grower can never go wrong with 1 to 2 days of flushing with plain water per week. Even though that can be overdoing it in some cases, a grower may want to be more safe than sorry.
The Drain to Waste System
A drain to waste system is basically a drip-watering system where a fertilized solution is used but not recirculated. Making a drip-watering system has been described on pages 52 to 56. Basically, any medium can be used, even the local dirt supply. Hopefully the medium has some air-holding capabilities. Sand, perlite, gravel, sawdust, vermiculite, peat moss, soilless mix, or calcium peroxide can be added to give more air-holding capabilities.
Calcium peroxide is the most portable way to oxygenate roots in soil or soilless mediums. Calcium peroxide has a 6-week life. PH of the medium should be 4.0 to 6.5. The pH of the solution is more important. A vegetating growth formula should be at 6.0 to 6.6 during vegetative growth and up to the first 2 weeks of flowering, and, then 5.5 to 6.3 during the duration of flowering. Parts per million should be 1,000 to 1,500PPM.
A good gravity system or tap can be used to get the water to the plants.
Tubing that is buried will be better protected from animals. However, frequent checks are important because there are curious animals that notice new objects in their territory. If a system is top-fed, the header line carrying the solution to the plants should be buried. Feeder lines can be attached to the underground header line and drawn to the top of the growing medium for top-feeding. If a predator does damage in this case, then solution will still drain out damaged parts so that plants can still get solution.
The diagram in this section shows a drip system too.
Outdoor NFT
Making Trenches
The first step is to dig a 6-inch to 2-foot trench in the dirt. The dirt should be sturdy, such as hardpan or clay.
The second step is to use two or more layers of black poly to coat the bottom of the trench.
On top of the black poly, any medium can be used to support the plants such as clay, sawdust, rockwool, river stones, granite, or fir bark. The width and depth of the channel depends on several factors, such as how big the plants are to be grown.
However, 2 to 3 gallons of medium easily can be used to grow a 6×6-foot plant. More can be used for huge plants, but staking may be more to deal with than it is worth.
If a gravel or clay that absorbs ions is used, it needs to be flushed almost as often as plants are fed.
Feeding for 4 to 5 days and flushing with plain water for 2 days is a plan that can be implemented from start to finish, or when plants begin to intake lots of food. This plan can be used for all growing mediums.
The trenches can receive solution pumped upward from the reservoir, or downward with a drain to waste from a high reservoir. If the system is not recirculating, it is best to have a slow water flow that effectively moves down the trench in order to keep the fertilizer costs to a minimum. An absorbent medium on the bottom of the NFT channel can help to hold more water and more plant food. Solution is delivered from the reservoir to the trenches with gravity, or with a pump.
Reservoir
If the ground is hard and only a negligible amount of water is lost to the ground, then the reservoir may need no liner (i.e. swimming pool liner or black poly plastic). A reservoir can be low maintenance if it can get a slow refill of ground water, or water from another source.
Fertilizer can be manually added to the reservoir, or an in-line fertilzer can be used. In-line fertilizer is available at garden centers and hydroponic stores.
Growing in Soil
Step 1: Finding and Preparing Quality Dirt
Quality dirt should be loosened with a shovel, pitchfork, claw, or rototiller. Then, if hand tools are used, a hole or a trench should be dug. The dirt should be placed in a pile with the stones removed. Placing a 1 to 2-inch layer of steer manure in the bottom of the hole or trench is recommended for the future roots. Soil tests can be made with inexpensive soil test kits available at garden centers. If tests are made, it is recommended to keep a log in order to reference how well a technique works in specific dirt.
Deciduous canopies such as alder trees often have good dirt, as do many riverbanks, areas where a river has overflowed and pushed the dirt away, arable farmland, and old quality gardens. Creek beds often contain a good dirt supply. Certain plant species reveal the quality of dirt beneath them, or they can reveal how easy a site is to prepare. Grassy areas often indicate a potential garden site.
Good dirt compacts when it is squeezed, then crumbles when it is broken up. Soils like this often hold decent moisture. Sandy soils won’t compact too well.
The next step is to put the aerated, fine dirt back into the hole. An option is to add more quality dirt to create a raised site, which allows for better drainage, or dirt can be put in a container (of 2 to 20 gallons).
Drainage at the site is an important factor. Poor drainage can be good in a very dry environment, yet be devastating in a rainforest. Fast drainage can cause overworking, which is why peat moss is so good. It holds water and nutrients much more effectively than soil, and it drains well. When peat is saturated, decent oxygen is still available to the plant’s roots, so that feeding can be effective. The grower must put two and two together at this point. Some soils drain so quickly that watering may be needed several times a week. Knowledge of dirt’s capabilities helps determine what the workload will be during the grow season.
Inevitably, the plant strain plays a large role in determining the drainage needs. For example, if the area of cultivation is dry for the whole growing season, the drainage factor is easy to know. However, if the rains come on in the autumn, a strain that finishes before the rain means less drainage is needed. But a strain that finishes in the rains needs good drainage and a decent supply of oxygen, and of course mold-resistance. Often, soils that drain poorly during adverse weather can bring on a mold problem as opposed to a grow medium that drains well and is not choked up from puddles of water.
Step 2: Liming
A grower can add fine dolomite lime 4 to 6 months before transplanting for the first season at the new site. A grower should apply and thoroughly mix the lime until the dirt pH hits near neutral (pH 7.0). Cheap test kits are available from garden centers to determine this. This is probably an investment worth making until the exact quantities of lime needed for the particular dirt type are determined. Dolomite lime has a neutral pH and makes this step a piece of cake. Adding it early is important to neutralize the pH, so that calcium and other elements can be utilized later during the grow season. It takes a few months for dolomite to break down and become available to the plants.
Step 3: Adding Material to Improve the Soil
Sand, perlite, peat moss, or vermiculite can now be added and evenly mixed to loosen and aerate the soil. Perlite will allow water to drain well and is therefore beneficial for a wetter soil. Vermiculite will hold water and is good for a drier soil. Sand will help heat the soil and is good for a wetter soil type, as it loosens up the dirt and allows for decent drainage. Peat holds water, air, and nutrient. Adding 1/2 peat moss and 1/3 parts perlite is a good addition to give the roots air, and to retain moisture and nutrient.
Step 4: Adding Fertilizer
A soil test is made with a soil test kit, or by taking a sample to a garden center for testing to determine levels of nitrogen, phosphorous, and potassium.
Option A: Organic Fertilizers
However, adding and thoroughly mixing 1 cup of blood meal, 2 cups of bonemeal, 1 cup of greensand, and 1 cup of kelp meal per plant is a safe combination to deliver the food supply until the flowers are in bloom. Optimal fertilizer amounts for specific dirt will require improvisation, because sandy soils don’t hold nutrients as effectively as peat or clay soils. The dried fertilizers can be added a few months prior to transplanting if thick, black plastic is used to cover the site to protect it from rain, which breaks down the dried fertilizers. The dried fertilizers can be added any time before transplanting, even on the same day. Soilless mix recipes can be used from pages 61 to 63 but, because all dirt is different, there are no guarantees. This is work to figure out the specifics. Organic matter such as a half a bag of composted steer manure (very cheap) per plant can be added to the soil as well.
The site can be flat to the ground or it can be a raised bed.
During vegetative growth and flowering, more food may be needed. Supplemental feedings are described in pages 67 to 68. Alternately, any recommended rate of a commercial fertilizer designed for flowering plants applied at half of full strength will work fine.
Option B: Using Slow-Release Chemical Fertilizers
Slow-release chemical fertilizers can be purchased with or without a protective osmocote. Fertilizers of this type can release over time periods such as 3 months, 6 months, 1 year, etc.
It is recommended to use a time release that stops expelling the fertilizer before the harvest date, so that excessive fertilizer release does not spoil the flower quality. Slow-release fertilizers come in all sorts of fancy numbers such as 6-8-6, 7-7-7, and 14-14-14. These particular numbers will work out quite fine.
Normally, a small handful is all that is needed to grow a hefty plant. Note that using too much can lead to plant burning: in this case plant leaves will curl over and many leaves will become brown and crispy.
During vegetative growth and flowering, more plant food may be needed. Any recommended rate of a commercial fertilizer applied at half of full strength works fine. A grower should not fertilize for the two weeks prior harvest.
Hydroponic / Aeroponic / Organic
Soil Feeding
How to Mix a Nutrient Solution
Mixing a nutrient solution can be as easy as doing what the fertilizer bottle says to apply. Most fertilizers’ recommended rates normally give a decent supply of the nutrients a plants needs. However, some are definitely better than others and are more specific to a specific plant’s needs. Brands such as Greenfire® Earth Juice, Welcome Harvest Farmtm, General Hydroponics®, Advance Nutrients®, Supernatural®, and others all give formulas for growing in soil, soilless, and hydroponic systems.
On the other hand, fertilizing can be made into a science depending on what the grower is trying to achieve. Some growers like to gain complete control over all the elements by customizing their formulas to particular feeding needs during all stages of growth. Determining the feeding needs of a particular strain is another important factor in working out a proper feeding formula so that a grower can give optimum nutrition and save costs.
It is possible to determine the parts per million (PPM) of a particular element such as nitrogen from the percentages of the elements listed on the fertilizer package.
Calculating Parts per Million
A chemical-fertilized nutrient solution should be at 1,000 to 1,500PPM to be on the safe side in most cases, but custom adjustments (i.e. 800PPM) can be made depending upon the plant. A TDS meter will give a reading in PPM (parts per million). Expensive meters measure a large span of elements and can be used to keep all feeding costs to the bare minimum because specific nutrients can be added when specific nutrients are used by the plants.
An organic, or a chemical-organic fertilized nutrient solution should be no higher than 1,500PPM. With an organic or a chemical-organic solution, a grower can push the quantity of certain elements because a lot of the fertilizer will not contain salts that hinder growth when they are in a solution in excess. For example, when Earth Juice® Grow and Earth Juice® Bloom are used to obtain the desired PPM of nitrogen and calcium, the PPM on a meter would be lower than if a solution of calcium nitrate was used to give the same PPM of nitrogen and calcium.
There will be dissolved solids in an organic hydroponic system from sources such as bat guano, Epsom salts (magnesium sulphate), sulphate of potash, humic acid, etc. However, some fertilizers will add nutrients but the PPM meter will not fluctuate. In a nutshell, this is the advantage of many organic fertilizers: no toxic salts. Results will be excellent if an organic solution is changed weekly, every 10 days, or every second week with a good fertilizing formula.
A solution can go unchanged for longer periods of time with additions of new nutrients from time to time, especially when plants are small and don’t feed as much. However, since plant nutrient requirements are always changing and some nutrient deficiencies are hard to detect, it is advised to change the solution regularly to save the hassle of determining what plant food is needed, and when. Also, just because plants are green doesn’t mean that they are growing at maximum production.
