Tabletops - which have picking costs 30 to 40 per cent lower than for bed-grown strawberry crops - are helping to reduce the adverse impact of a severe labour shortage for Kent grower Paul Kelsey.

"Two years ago we had about 100 acres (40.4ha) of (bed-grown) strawberries but this year we're down to 65 to 70 acres (26.3 to 28.3ha) and next year we'll have only 45 to 50 acres (18.2 to 20.2ha). The reality is that we'll then be cropping as much, if not more, than two years ago," Kelsey told growers during an East Kent Fruit Society walk around his 40ha berry fruit enterprise at Quaives Farm, Wickhambreaux, Canterbury on 2 September.

By 2010, all of his strawberries will be grown on tabletops. The main advantage is that picking costs are lower, but there are other benefits. These include elimination of the need for soil sterilisation and the moving of polytunnels, more effective vine weevil control (with nematodes applied through the trickle system) and greater control over plant growth.

"Pickers don't want to be on their knees all day," said Kelsey. "Getting them has been an absolute nightmare this season. In the next two or three years a lot of growers will be questioning what they are doing and whether it's still worthwhile."

Just how hard he has been hit by the labour shortage was emphasised by his farm manager, John Rix. He said he wanted to peak with 200 pickers but never had more than 72, resulting in the loss of around 200 tonnes of fruit.

The visitors to Quaives Farm learned that raspberries and blackberries, both of which are increasingly in demand, are replacing some of Kelsey's strawberry crops. Currently the farm has 6.1ha of raspberries and another 4ha will be planted next year. All of the raspberry varieties, including Maravilla and Isabel, were bred by Driscoll's.

The crop is grown from root cuttings supplied by Berry Gardens. They are planted in March end-to-end in a ploughed-out furrow, which is then back-filled. Rix explained that, in January, the support structure is removed and the old cane cut back tight with a rotary mower. Then in June, when the new growth is 45-60cm tall, it is thinned to around 12 canes per metre.

The raspberry picking season began in late August and last year did not finish until mid-November. The budgeted yield of mature plantations is five tonnes/acre "but we hope to get seven tonnes", said Kelsey. Picking costs range from 90p/kg to £1.05/kg. Maravilla is the cheapest to pick thanks to its very large fruit, which averages 9g per berry.

By the end of this season he will have 18.5 acres (7.5ha) of blackberries comprising Karaka Black, Carmel and Subsidian. The visitors saw some Carmel, a large-fruited variety planted in 2006 as 9cm plug plants 1m apart in the row. Last year it yielded around three tonnes/acre and it is expected to do eight tonnes/acre this season.

"Varieties like this can open up the blackberry market," asserted Kelsey. "We began picking it in mid-July and it will pick for another six weeks (making 12 weeks in all). It's amazing where the fruit keeps coming from. We expect the plantation to have a nine- or 10-year life."

His first tabletop block - comprising 7.5 acres (3ha) of the Italian variety Elsinore - cropped last year for the first time. It yielded 20 tonnes/acre, producing a flush in June and July and another starting in early September.

"A+" plants were used in this block but "A" and misted-tip plug plants of the same variety are being tried as well. The latter have produced better-looking plants. Next season, tray plants will be tried to see if they produce better results. They should start cropping earlier in the season, Kelsey predicted.

The tabletops were installed four rows to each polytunnel with the two centre rows 2.1m apart and the others 1.1m apart. The wide centre alley allows the picked fruit to be handled by a tractor and trailer and the plants to be sprayed in a single pass with a tractor rear-mounted Italian air-assisted Carraro, supplied by Cranbrook agricultural engineer NP Seymour.

The sprayer's overhead boom carries eight nozzles, two for each row, but Rix said that extra-low, upward-directed nozzles would be fitted to improve coverage of the undersides of the trusses and the leaves above them. This system has the advantage over the usual tunnel spraying equipment of having an orchard-type tractor fitted with a cab to provide full protection for the driver against the spray.