Growing Systems


The vertical bag culture growing system developed by Hydro-Gardens is adaptable to any size greenhouse. Many different combinations of timers, injectors or nutrient holding tanks can be used. The basic system includes 5 gallon black growing bags with a sprayer in each bag. The sprayer has 24″ spaghetti tube which connects to a 3/4″ or 1″ poly pipe nutrient line running the length of the greenhouse. The spaghetti line is inserted into the poly line with a simple punching tool. No glue or grommets are required.

A 24 volt automatic valve in the center of each zone (single or multiple rows) is attached to an underground PVC header pipe which runs across the width of the greenhouse. A PVC tee is placed in the header line for each automatic valve and is connected to the poly line with a poly combination tee. Since the valve is normally closed until energized by the control device, the header line is always under pressure (30-50 psi). Each zone is fed individually as programmed and activated by the Solar Irrigation Controller, or activated by the sequence timer.

The nutrient supply system (injector, pump, etc.) is designed according to the size of the greenhouse and type of crop to be grown. For example, a typical 5 row greenhouse only needs the Solar Controller. A 24 zone greenhouse may also need a 24 station timer. Using a sequence timer to feed one row at a time may be less expensive than increasing the injector size to water multiple rows. If a large nutrient holding tank is used with a pump sufficient to feed all rows at one time, then a sequence timer is not required. However, it is apparent that an injector and solar controller system is far more practical, less expensive, and requires less space than installing large nutrient tanks.

The selection of the injector system and control device(s) is an important part of the overall design. Certain factors must be known: 1) the number of zones, 2) the number of feeders per zone, 3) the water volume available to the greenhouse, and 4) the water quality. Hydro-Gardens offers designs for any size greenhouse and any major type of crop. Solid state timers are available in an assortment of numbers of stations. The timer can be activated by the solar controller which measures available sunlight. You adjust the solar controller to water the plants only when they are receiving adequate sunlight. Solar controller models with 15 stations or complete greenhouse controllers that use the same 15 stations for irrigation, heat, cooling & CO2 etc are available.

Hydro-Gardens offers three types of injectors. The Dosmatic Injectors & Anderson Injectors are driven and controlled by water volume. The less expensive Chem-Feed injectors are driven by an electric motor. All provide the function of changing our Chem-Gro fertilizers from the concentrated form into a plant usable fertilizer by metering out the correct amount of concentrate into the water supply line.

Anderson & Dosmatic injectors are designed to handle variable flow rates of water. There are sizes with maximum water flow rates of 20, 30, 50 and higher gallons per minute (GPM). They operate accurately anywhere from 1 GPM to their maximum. The dial on each pump head of the Anderson water driven injector is easily adjustable to deliver the desired quantity of concentrated fertilizer to the fresh water supply line going to your plants. The pumping action of the pump heads is controlled by the water motor. Each Dosmatic is individually adjustable with dosage rings, and uses a piston to deliver concentrate. The value of both injectors is the fact that each delivers the correct volume of fertilizer concentrate over a wide range of fluctuating water pressures and volumes. These injectors are very accurate, dependable, and completely automated. More specifications can be found in the pages of this catalog.

The Chem-Feed injector is an electric motor driven pump that delivers a constant flow of fertilizer concentrate to the fresh water supply going to your plants based on the dial setting on the face of the pump. It’s accuracy is totally dependent on the volume of fresh water delivered to the plants. If your fresh water system cannot deliver a constant volume of water, you will not be able to accurately adjust the pump to deliver the correct amount of fertilizer concentrate. The Dole 10 GPM regulator adjusts flow rates that are greater than 10 GPM, down to 10 GPM. The maximum number of sprayers per zone is about 140. Thus the Chem-Feed system is dependent upon having a constant PSI and water flow. For this type of injector system all individual rows (zones) of plants must have the same number of sprayers. This will guarantee equivalent dilute solutions to each row (zone).

It should be apparent that a properly engineered design can have long term labor and operating cost savings and can enhance your crop production. Hydro-Gardens has the experience required, and will be glad to design a system for your needs.


The top spray feeding system was developed in 1972 by Hydro-Gardens for controlled watering and feeding of plants in vertical bags. The Vertical Bag System utilizes a 5 “gallon” (20 liter) upright plastic bag with drain holes. Hydro-Gardens’ plastic bags are inexpensive, lightweight, and will last several years. Our bags are manufactured from a specially formulated plastic that contains ultra-violet light inhibitors. They easily outlast plain plastic bags. They are extremely flexible and adaptable to many plants including tomatoes, European cucumbers, peppers, roses and trees. In 2004 Hydro-Gardens developed the EZ Gro Bags. These are 5 gallon bags pre-filled with coir. Simply put your sprayer/dripper in the bag, turn on the water, and now you have a vertical bag system ready to go. This new design is much more labor efficient and helps the growers to cut costs. Click Here to see pictures.

Each container is watered with a uniform pattern of nutrient solution for a very short period of time, usually one minute every 1 to 2 hours during the daylight period for mature crops. The amount of irrigation time and the frequency depend on the crop, variety, age of the plant, season of the year, and type of growing media used. Each vertical container has drain holes in the bottom. When the nutrient solution is properly adjusted, plants can seldom be over watered or over fertilized.

Fertilization is simplified tremendously by the use of a very accurate injector (ratio feeder) in conjunction with our solar irrigation controller or a sequence timer/solar controller combination. The amount of nutrient is carefully regulated automatically by volume and concentration to each plant. The pH is automatically maintained in the proper range with the injector system.

Since every greenhouse cannot have a testing laboratory, it is necessary to start with standard feeding schedules and standard formulas. First, a water sample should be taken and sent to a reputable laboratory to verify essential and non-essential levels of elements in your water source. Once the plant is large enough to take a leaf sample, the nutritional balance can be monitored and small changes can be made as the plant matures. The important factor of this system is that one can regulate the nutrition being applied to the plants with very little labor. The results are rapid since the nutrients are placed right at the root zone. In the bag system, the roots are contained, and each plant is fed uniformly and equally every time. Under these conditions, the plants achieve maximum growth if the environment is controlled. The bag system is safe, simple and creates an ideal environment for the root system. Root zone temperature can be maintained at a higher level than if grown in the greenhouse soil.

Many growing medias are used with the vertical or bag system. One of the most popular is the EZ Grow 5 Gal Bag coconut fiber/perlite blend. This mixture is ideal since it is pH adjusted, has good water and nutrient holding capabilities, and remains porous enough to maintain good aeration of the root zone. Some of the more common medias being used are:

** 100% coconut fiber (EZ Gro Bag – COIR)
** 70% EZ Gro Bag – COIR, 30% coarse perlite
** 100% peat-lite mixtures; such as Pro-Mix BX
** 40% peat-lite w/ 60% sawdust, sand or rice hulls
** 40% peat moss, 40% vermiculite and 20% perlite
** 40% peat moss, 40% vermiculite and 20% sand
** Rockwool/COIR mixtures
** Rockwool/peat-lite mixtures
** Rockwool/peat mixtures
** 30% peat moss and aged, coarse sawdust
** Straight aged redwood sawdust
** Coarse washed stucco grade sand
** Perlite
** Aged pine bark

NOTE: Many other media combinations may work well when used in conjunction with the proper nutrient concentrations and watering schedules. Send a sample to one of the testing labs listed in this catalog.

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