We used to get the harvest in without EU migrants before we joined the EU.
Who picked the fruit before the Eastern Europeans?
A brief summary of agricultural work in the last 100 years.
Between the wars, crops were harvested by itinerant workers who moved around the country getting work according to the seasons, by 'gypsies' and by seasonal workers such as East End hop-pickers. Work was hard, wages were at subsistence level and conditions abysmal. ‘Besides these starvation wages, the hop-picker has to put up with rules which reduce him practically to a slave,’ as George Orwell wrote from his first-hand experience - www.orwellfoundation.com/the-orwell-foundation/orwell/essays-and-other-works/hop-picking/ or hoppicking.wordpress.com/
During WW2, agricultural work was done by people evacuated from the cities, by the Women’s Land Army and by prisoners of war and occasionally by soldiers.
After WW2 the men returned to the UK and to the task of rebuilding the country. There was a need for manpower in factories and construction and as wages were far higher than in agriculture, the industry faced a critical shortage of workers. 400,000 German POWs were prevented from returning to Germany until 1948 (despite the war ending in 1945) and were forced to work in agriculture and construction. Some did so voluntarily (e.g. Bert Trautmann, who later played football for Man City) as they preferred to stay in the UK than return to a war-ravaged Europe. In addition, 100,000 Poles were allowed to stay in the UK as well as a similar number from other Easter European states who were fearful of returning to their home countries which were by then under Soviet occupation.
Seasonal Agricultural Workers Scheme – 1945 This initially allowed foreign students, then anyone, to come and work during harvests.
blogs.exeter.ac.uk/exeterblog/blog/2016/09/19/who-picked-british-fruit-and-veg-before-migrant-workers/
I'll also point out that such was the shortage of food after the war that rationing continued until 1954 - 9 years after the end of hostilities.