Two teams of eight people from the finance department at diversified technology company 3M in Cain Road each spent a day clearing bushes, brambles and small trees at Kennel Lane special school in Priestwood.
The school will turn the cleared patch into an outdoor teaching area for students aged 14-19 to learn horticulture.
Karen Malcolm, the school's secondary manager, said: "With the support from a charity bid through 'Dig It' and a generous donation of £5,000 from the Lisa May Foundation, we hope to be able to construct two polytunnels, raised beds, an allotment area, seating, pathways and covered work areas to allow for an all-weather learning experience.
"Kennel Lane aims to embed enterprise work into this project so that students will be involved in planting and harvesting crops to sell and eat through food technology lessons, as well as life skills projects and vocational enterprise days where we will sell products to the public.
"We were faced with the monumental task of tackling all the undergrowth that had become established over the years and it's wonderful that the 3M volunteers came along and did it all for us."
The staff took part in the work through the 3M 4Good scheme, which gives every full-time employee the opportunity to do a day's voluntary work in the community on company time.
Accountant Rich Ball, who coordinated the volunteers, said: "We split into two teams doing a day each and managed to get all the undergrowth cleared and the soil prepared - thanks to the loan of a rotavator from HSS in Bracknell."