NFT Fixed Bench Systems are a popular choice for commercial hydroponic lettuce and herb growers.
They can be operated by one grower and everything is fixed in position for the lifetime of the system. This makes it very easy for one or more staff members to plant, harvest and clean the system.
An NFT Fixed Bench System is especially suitable for growers who wish to grow a wide variety of plants, which mature at different ages or require regular access for harvesting.
In a typical Fixed Bench NFT system, you can grow approximately 11 plants per square metre of greenhouse area. (Growers requiring a higher crop density should consider our NFT Sliding Bench (MGS) systems discussed on a separate page).
Lettuce growers can expect to achieve a minimum of 8 crops per year in the Fixed Bench system based on a good-sized lettuce sold by weight.
13 – 14 crops per year or more can be achieved if a smaller size lettuce is to be grown, or if a larger seedling was produced in the nursery area to enable less time in the NFT system.
Pure Hydroponics can design a nursery system and NFT system to suit any preference.
Pure Hydroponics supports a 2-stage growing system. Seedlings are raised in an Ebb and Flow propagation system. Then, when the seedlings are ready for transplanting, they are transplanted into the main NFT system. The root system is therefore only disturbed once before harvest.
The Fixed Bench systems are most popular for Lettuces, Herbs, Leafy Greens, Chinese Vegetables and Strawberries.
System Specifications
- The NFT Fixed benches typically use 100x50mm gully and are most usually 8 gullies wide (1.6m wide) x 6 metres or 12 metres long (Longer gullies up to 18m long can be used in cooler climates).
- A bench which is 8 gullies wide means that the centre of the bench is easily accessible from both sides during planting or harvesting. Narrower benches are located alongside the greenhouse sidewalls.
- The fixed benches typically have a minimum 850mm wide pathway around all four corners of the bench. This allows easy access at all times and enables trolleys and other equipment to be used around the benches without any restrictions.
- Support frames are appropriately placed to support the gully from beneath. Failure to provide adequate support frames can result in sagging of the gully between the supports when the gullies are fully planted. This can result in ponding or a deeper flow of nutrient solution inside the gully resulting in root stress.
- PVC Saddles are placed over the gullies on every second support frame to lock the gullies in place on the top of the bench. This prevents any movement during storms or when the gullies are bumped during planting or harvesting. (Some gully designs have a small lip on the base to allow a screw to be inserted to fix the gully in place).
- At one end of the NFT Fixed Bench is the Feedpipe system which pumps a thin film of nutrient solution into the top of each gully. The feed pipe system has an adjustable control valve to allow a 1 litre per minute flow rate to be maintained down each 100x50mm gully. (Wider, shorter or longer gullies require a slightly different flow rate).
- Two 4mm I.D feeder microtubes per gully are used so that if one blocks the other can still function. A rubber top hat grommet holds the microtubes in place on each gully.
- At the opposite end of the bench a catchment system is installed. This is usually a light proof gutter with 8 slots to allow the tips of each gully to be inserted. As the nutrient solution flows out of the gullies and into the catchment system it is diverted into a common area where it falls into a vertical return pipe and down into a gently sloping return pipe. The return pipe collects all the return solution from nearby benches and directs it back to the mixing tank in the pump room.
- A sanitation system in the pump room targets any pathogens which may be introduced into the mixing tank.
- A minimum 1:40 slope is maintained down each gully to enable a thin film of nutrient solution to be maintained and to prevent any ponding.
- Growers can steer the crops to be more vegetative or generative or to have hard or soft foliage by adjusting the nutrient strength (EC) of the nutrient solution.
- Gullies are cleaned on the bench using a gully brush or our Hover Blaster gully cleaner. Or the grower can choose to use a 2 piece clip on lid gully which allows the lid of the gully to be removed for easy cleaning.
Pure Hydroponics can design and supply full Fixed Bench systems to fit an existing greenhouse or we can supply a turn-key system comprising of an NFT Fixed bench system, greenhouse and climate control.
For growers located in distant countries we also offer a Design and Shopping List service which allows growers to source PVC pipework and common equipment locally. Pure Hydroponics can then assist with any specialist equipment that may not be available such as NFT gullies, dosing control system and NFT system accessories. This keeps the freight and set up costs down for the grower and supports their local economy.
The grower can install the systems themselves using local labour with the assistance of technical drawings and online support from Pure Hydroponics. Or we can supply an onsite installation supervisor to supervise local labour and provide full training once the system is commissioned.
The main objective is to get new growers set up with a properly designed hydroponic system, at the best price possible.
We can then offer a full support package such as online and onsite advisory, nutrition and consumables to ensure the grower can secure their place in the market, repay their investment and be successful.
Please contact Pure Hydroponics for a turn-key NFT Fixed Bench system quotation or our Design and Shopping List service.
All interested parties must complete the attached Commercial Design Questionnaire as part of their enquiry.
Commercial System Design Questionnaire
