Kenyans have been given a special holiday to plant 100 million trees as part of the government's goal to plant 15 billion trees in 10 years.
The holiday allows "each and every Kenyan to own the initiative", according to Environment Minister Soipan Tuya.
Each Kenyan is being encouraged to plant at least two seedlings, leading to the 100-million target.
About 150 million seedlings have been made available in public nurseries.
The government will be providing the seedlings for free at its forest agency centres for Kenyans to plant in designated public areas.
But it has also encouraged Kenyans to buy at least two seedlings to plant on their own land.
President William Ruto is leading the exercise in Makueni in the east of the country. Cabinet ministers have been sent to other regions to lead the process alongside county governors.
The tree planting will be monitored through an internet app, which monitors the exercise by allowing individuals and organisations to record activities, including the plant species, number and date planted.
The Jaza Miti app will also help people plant the appropriate seedlings by matching the site with the appropriate species, according to the environment ministry.
Ms Tuya told local Citizen TV on Sunday night that the response had been "amazing" and there had already been two million registrations on the app by Sunday.
She however said the planting would not happen in the north-eastern region, where there have been floods.
The country is currently grappling with heavy El Niño rains that have killed dozens of people, displaced thousands and damaged infrastructure - with the northern region most affected.
Kenyans have broadly welcomed the tree-planting initiative while also noting some challenges.
Environmentalist Teresa Muthoni told the OceanNewsUK that the initiative was a "very good idea", but that the exercise was not organised in a way that would ensure everyone was out there planting trees.
She said "many people have to continue with their work to put food on the table... it is coming at a time when our economy is not doing well so a lot of people are struggling financially".
She also noted that "a lot of the 150 million trees available" in public nurseries were exotic. "It is very important to plant the right trees in the right place," she said.
The government has also been criticised for championing tree planting while failing to tame illegal logging in public forests - it recently lifted a ban on logging.
But on Sunday, the minister defended the decision, saying only forests designed for commercial purposes were affected - about 5% of the total.
She said this was necessary to feed the local wood demand and create jobs, adding that the government was taking action against illegal loggers in other forests.
She said the initiative would help tackle food security and was also a "mitigation against climate change" to address the cyclical drought and floods in the country.
Ms Tuya said the exercise will continue beyond the special holiday and expects that 500 million trees will have been planted by the end of the rainy season in December.
