By Lewis Machipisa
BBC Network Africa, Rumbek
The first sign of rain clouds for students at Tiboro School in Yeri in South Sudan means that classes are abandoned.
The village school is little more than a few benches under a tree; the few textbooks available are used by their teacher Repent Khamis Eliashas to prepare lessons.
Mr Eliashas has not had any formal training. Sometimes he teaches three different classes at the same time, moving from one to another to check their progress.
Two hours drive from Yeri is Rumbek, the nearest city, where teachers have been on strike over the non-payment of their salaries for the last four months.
"I've never got any training," admits John, one of the more qualified teachers at Rumbek Secondary, the only senior school in Lakes State.
"I'm just trying my best because I at least finished my secondary level and my advanced level [the equivalent of A level]. I give them what I have, but of course I still require certain training - even how to handle students."
Two and a half years after a peace deal ended a 21-year civil war, officials in the autonomous south are attempting to tackle education - a sector that literally needs to be built from scratch.
Most teachers are volunteers or receive small stipends from non-governmental organisations or churches.
Three-quarters of adults are illiterate and the UN says only about 22% of an estimated 2.2m school-age children are enrolled - with about 1% of girls finishing primary school.
Many of these fourth graders are old enough to have finished school
But with free schooling, many of those who missed out during the war are eager to learn - some of the junior students in Mr Eliashas' third and fourth grade classes are old enough to be at college.
Lakes State Governor Daniel Awet Akot agrees finding qualified teachers is one of the main challenge his state faces.
"We lack teachers. There are some we trained during the war, but there are very few - it cannot cover every buma [village]," he says.
"Each buma has a school and we have over 100 bumas. In a school of 800 pupils there are only four or five teachers - that's not enough."
For the governor, the budget, controlled by the government of South Sudan, is the problem.
"If we had money we could invite teachers from Kenya and Uganda - 100 or 200 teachers - but because we do not have cash we cannot do that," he explains.
However, South Sudan Minister of Education Gordon Maker Abol says recruitment and training cannot begin in Lakes States until a survey of schools is completed.
"At present we have over 1,500 teachers - both primary level and secondary school [in south Sudan]," he says.
"In the war, schools were established without plan - a community in a given village would clean a very big tree and say: 'This is our school'.
"So I'm now surveying to see which schools were built and which of those are under the trees. I will also see the distance of the schools under the trees so that I can try to merge them."
Other states, which have completed their surveys, have decided to recruit from neighbouring countries - and it is hoped that recruits can be found from the thousands of returnees to the south.
In Lakes State, about 150 young returnees who completed high school in Kenya and Uganda have registered to teach and are awaiting a crash teacher-training course.
A coalition of aid agencies has launched the Basic Education Learning Centres (BELC) project to train about 1,000 elementary teachers over the next five years.
Repent Khamis Eliashas mainly teaches from his own notes
But far more needs to be done - the UN estimates more than 9,000 teachers are needed across South Sudan's 10 states if all eligible children are to go to school.
Another concern for the sector is the curriculum, which has yet to be completed by Mr Abol's ministry.
Most pupils are taught from textbooks from Kenya or Uganda and the curriculum can even be different at the same school, as there are not enough books to go around.
Sometimes, books are translated from Arabic - the language used in northern Sudan - but many teachers, who teach in the local language with a spattering of poor English, are reluctant to do this.
Despite the obstacles, south Sudanese do have great hope and commitment about establishing a vibrant new education system.
"Our morale is now low because we have not been paid for months," said a teacher in Rumbek, who asked not to be named because of the recent strike.
"It's not easy as we have to pay for food, accommodation and sometimes it's difficult to explain to people why we don't have money. But we will keep doing our job," he says.
But as the children at Tiboro School bade me farewell in song, I could not help but worry that unless urgent measures are taken to breath life into the education sector, their future is bleak.