Article taken from Fruit Grower Magazine – February 2013, p.35-36
Substrate systems have been adopted by most of the UK’s major strawberry growers over the past few years and Botanicoir has been at the forefront of the development and improvement, recently launching its new and improved “Precision Plus” graded mix. Lack of pest and disease-free land, plus the loss of reliable soil sterilants have forced many growers down this road. Planning issues and picking costs have also driven growers to leave the soil and embrace substrate growing.
Improvements in the quality of coir substrate, and the knowledge associated with its use, have reduced the risks for growers who wish to move to substrate for the first time. Coir is now the substrate of choice, with most growers having moved on from the peat bag that was more common 10 years ago. Plant health, yields and potential reusability have all helped make coir the success it is today.
Coir can be a much more consistent product than peat, as the particles are manufactured to a physical specification, enabling us to produce a growing media that has the combination of grades and fibres to ensure the ideal Air Filled Porosity for the crop concerned. The chemical and physical properties of any substrate are key to its success and there are now clear guidelines on the requirements for soft fruit crops. Botanicoir’s unique production process enables them to achieve these physical targets consistently, slab after slab. Furthermore, Botanicoir have developed a buffering technique that will also ensure that the chemical levels are just as consistent. This is particularly important when producing coir for strawberry production that must be FULLY washed and buffered. Careful and thorough treatment with a quality branded Calcium Nitrate during the production process removes unwanted salts whilst ensuring initial calcium levels are high enough in the material. Recently, the grading has been improved even further with the introduction of the new Precision Plus grade, developed as a result of rigorous trials with leading UK growers.
Until recently the 1m x 20cm x 8cm washed, buffered and graded Botanicoir strawberry bag has been their most popular system used by growers. The slab is delivered as a dehydrated product, then simply rehydrated and planted.
However, Botanicoir say that they are now seeing more growers interested in exploring the possibility of using a trough substrate system. We spoke to Mark Davies, who heads up the Soft Fruit Business at Botanicoir’s partner company, Agrovista UK, about his thoughts on the debate of bags vs. troughs.
“There are definitely pros and cons to both systems,” says Mark, “The Botanicoir grow bags will fit a variety of support systems including both pipe and wire systems, as well as gutter systems. Troughs are quite specific in their support requirements and so if a grower has an existing tabletop area this may dictate whether he can use troughs, and if so, which trough he uses.
The initial investment is less to set up a bag system than troughs. However, a note of caution – if you are considering developing a system around bags and then moving on to troughs in the future, make sure that you support system is compatible for both! A trough system may prove to be more economical in the longer term, as the replacement costs of the coir are less than purchasing more bags. However, troughs should always be washed and sterilised when the coir is changed.”
When asked about the question of flexibility, it seems there this is a very talked about point. Mark explains, “There is no doubt that trough systems offer greater flexibility. Firstly, the grower is not tied to planting a set number of plants per metre, as is the case with a strawberry bag with pre-cut planting holes. This means a trough can be growing 5 plants per linear metre one year and 10 the next. It also means that growers can make last minute changes to their plant densities should their plants arrive either larger or smaller than anticipated. One-meter long troughs, which are extremely popular in Holland, allow greater flexibility in plant numbers per linear metre – either odd or even numbers. Using 50cm troughs will restrict the grower to planting even numbers per linear metre, as all troughs must have equal plant numbers to avoid inconsistencies in water and fertiliser applications. Secondly, a trough can be moved around at any stage of the production process without fear of root disturbance, allowing growers to exploit multi cropping systems.”
“On the other hand,” Mark goes on to say, “when planting troughs, growers must be careful to ensure that the plants are placed evenly throughout the trough. There are no pre-set planting positions as there are with a grow bag with pre-cut planting holes, so this will call for greater supervision. Both the Bato troughs and the Botanicoir Precision Plus Grow Bags are available in black or white, enabling the grower to use this to his advantage when planning his cropping programme with either system. The Botanicoir Precision Plus Naked Strawberry Slab offers growers an efficient solution to filling troughs, without the need for specialist trough filling equipment, or handling vast quantities of bulk coir as used to be the case. It is the aim of Botanicoir for growers to be able to reuse their coir for as many seasons as possible. On some occasions the coir may need to be “fluffed” between crops and this is more easily done in a grow bag than a rigid trough.”
“And there are a whole host of other pros and cons to take into consideration when deciding on a growing system,” says Mark, “For example, trough systems will often have the surface exposed which allows growers to consider using a pressure compensated drip pipe laid on the coir surface, but care must be taken not to encourage root growth into the drippers causing potential problems. Bag systems must be irrigated with a “woodpecker” type drip system. Then there is the training of fruit trusses, which must be good in trough systems to avoid fruit sitting on the coir surface. Water use will be slightly more with an exposed trough surface due to increased evaporation from the surface when compared to the more enclosed strawberry bag. The germination of windblown weed seeds could also be more of an issue with an exposed trough surface, but good farm hygiene, and the fact that the surface of coir will stay relatively dry, should minimise this risk.
When deciding to use a trough system, trough choice is particularly important. The Bato range come with legs at the base, ensuring that when the trough is placed on the ground, contact with the soil surface is avoided reducing the potential spread of soil borne pests and diseases. To achieve this with a grow bag, some sort of support system must be adopted.”
Mark concludes by saying, “As you can see, there are advantages and disadvantages to both systems. At Agrovista, we would expect to take all these factors into consideration when asked for our advice on which system a grower should adopt. We would then make a recommendation on an individual farm basis, and that recommendation will certainly vary from farm to farm.”