Schools in South Holland may be forced to close on Tuesday, October 1 as teachers go on strike.
The two biggest teaching unions are walking out across the East Midlands in a row over pay, pensions, working conditions and jobs.
An all-out national strike – on a date yet to be announced in the autumn term – will follow.
Individual schools will be left to make the call on whether or not to close, but one South Holland headteacher says it’s too early to say what impact the strikes will have.
Doreen Bamford, acting head at Spalding High School, said: “We have dealt with this before when there has been strike action and what we have tried to do is keep the school open for at least a proportion of the students.”
Lincolnshire County Council school services manager David Robinson said schools sometimes won’t know until the day of the strike whether they must close.
He said: “In times of strike action it is up to individual schools to make preparations for the loss of staff and make a decision on whether there is enough cover to enable the school to stay open safely.
“The health and safety of pupils is the most important thing.
“It is not clear that union officials have to let school managers know which staff are striking and sometimes this can lead to schools having to make a decision on the day.
“However, when strike action has happened before, in nearly all cases school staff in Lincolnshire have given their schools plenty of notice that they will be taking strike action, allowing alternative plans to be put in place at an early stage.”
The NUT and NASUWT are protesting about cuts in their pensions and reforms that will see pay linked to pensions and headteachers given “greater flexibility” over salaries.