Making your bed.

The great debate for UK growers on strawberry beds is size - height and width. So what do we see elsewhere in the world and what can we learn.

Well our closest neighbours in Holland and Belgium, those few still growing in the soil grow in what looks at first like a very low tech system on the flat. A large proportion of soil-grown crops are 60 day Elsanta, where the only crop picked is from that first production. The short life of the plant helps reduce the need for sterilisation. growing on the flat aids planting the "waiting bed" plants needed to produce economic yields. The irrigation system is often buried "pop-up" sprinklers needed for establishment and the soil is always light land. So for these growers the disadvantages of a bed system out weigh the advantages.

As always we look to the US for ideas and in particular California. One this is for sure there is not a single system adopted for all locations by all growers. Most production there is on a raised bed, a system originally adopted primarily to ensure that when you get exceptionally high rain fall the plant is not left sitting in water for days on end.

It is this principle of providing the strawberry plant with its crown and part of its root system in a well-drained environment that is at the heart of all bed systems. To this we can add further advantages by raising the bed height further we reduce labour input for planting and importantly picking. As the bed height is raised we also reduce the harmful effects of over irrigating.

In Spain most production is now on high two row beds at 1.1 and 1.2m widths. This system suits production and starts in January and finishes in June. The high two-row bed warms quickly in the spring promoting earlier yield and allows accurate picking for the fresh market from start to finish. The relatively narrow bed has the advantage of being more three-dimensional than production on the flat or even wide beds. Light can get into the plant from the sides as the leaf canopy falls and (most of the) fruit hangs conveniently for picking along the row sides.

The production in Spain is primarily camarosa and the same variety growin in Southern California is growin on a quite different system. Californian Camarosa is grown on high but wide beds and it is the everbearer production in Northern California that is grown on two row beds. In california Camarosa production is for the fresh market December to late April or until superior everbearers start fortuerh north. During the winter and spring period Camarosa is quite a small plant and you can pick quite accurately at this time for the fresh market by May and June the plant is larger and fruit size more variable and fruit is destined for commercial freezers.

In the north many growers use two row beds for everbearers that start in April and crop through to September of October. Here the production is aimed solely at the fresh market where picking accuracy is key to maintaining quality.

So here in the UK we debate bed width and planting density with out own set of climatic and marketing parameters. In my mind there are a few topics that require the minimum amount of debatre and first amongst these are bed height. The higher the bed the better as far as I am concerned. The limiting factor is tractor clearance. More difficult is the choice between narrow two row beds or wider three or four row systems.

The scientist in me is frustrated by the difficulties in trialling all the variables - bed width, row spacing, interplant spacing, irrigation tape placement. the difficulty comes in being able to replicate in all trials the crucial influence of soil structure in the beds and this really only highlights the importance of being able to find a suitable bed maker for any given soil type.

As a grower I am spending out more than half of my fruit return son labour so this has to be a kep part to my decision making process. To this end I would tend towards two row beds to increase picking speed and save more money in the packhouse from picking accuracy. The speed of picking however can all be undone by having the beds too far apart i.e. at 1.5m centres with pickers having to shuffle across to pick half of each bed.

For wide beds you need to be high 35cm plus to maximise picking speed. Plant density becomes more critical and here calculating planting distances through trial and error as each variety by soil type by fertigation combination will be different. In essence wide beds with three or four rows give higher plant populations per hectare. At the right density of planting you move into a new area of yield potential. Conventional low two row beds of Everest cropping 25 tonnes per hectare are competing with 35 to 40 tonnes due entirely to increased plant populations.

Making your beds

If you look at beds in California or Huelva, Spain the first thing that strikes you is how light the soil is. Soils range from coarse beach sand to what we here would call light land. occasionally in either country you hear strawberry growers talking abotu heavy land but that is where the sand has a small fraction of silt.

In the Uk few growers have true what I would term light land and therefore taking machinery directly from overseas is not always going to be an option. Most bed makers I see used commercial overseas work with plough or disk shares lifting soil into a tunnel bed former which then compacts the soil into shape. With heavier land there are two options a system based on a double pass or using a former with a powered "cultivator" to lift the soil into the former.

Who is the technology for?

With an increasing reliance on ever bearers and their potential to deliver 1000g plus per plant our ability to deliver much higher plant density through high close beds puts a good Uk grower on a level playing field for yield per hectare with any serious competition furing the UK  season.

Kitting out with new tractors, bed machinery, sprayers, picking carts is expensive but altogether a far better investment than any substrate based intensive system.

Spring 2003

Crop PRO-TECH Ltd the UK leading supplier of Spanish Tunnels, Polytunnels, Greenhouses, Bed formers, Poly-layers, Poly winder, Horticultural Machinery, Table Tops, Growing Systems, Agricultural nettings, Agricultural Polythene.