Landscape architect Gareth Wilson, who created the garden, praised the actions of the woman, who was believed to be a regular visitor to the show.
“I want to thank her and buy her a drink,” he told The Telegraph. “She acted quickly and thoughtfully. I’d say she’s a hero.”
He labeled the offenders “damned idiots” and added: “It’s devastating to see something you’ve put your heart and soul into being destroyed. It’s just really disappointing to ruin someone’s work.
“The people here are gardeners. They all believe in sustainability, they care about the earth, they are interested in plants.”
He said the RHS was one of the “most sustainable organizations in the world” and for a design to be accepted it must use as much recycled material as possible.
“I can’t believe they didn’t do their research,” he said.
“You see a woman putting paint on the plants – if you’re a lover of the earth, why are you doing this?”
Paul Hervey-Brookes, the garden’s designer, said on Twitter that the stunt had “permanently damaged” his creation, which had been awarded the silver-plated medal.
Veteran designer Mark Gregory, known as the King of Chelsea, said the protesters had shot themselves in the foot.
“Why would you ever do this at a flower show? It seems ridiculous,” he said. “This is all about greening. I think they actually damaged their business.
The activists were named as Stephanie Golder, 35, Naomi Goddard, 58, a retired landscape engineer, and Rosa Hicks, 28.
In a statement released after their arrest, Ms Goddard, who is now a town clerk in Hebden Bridge, West Yorkshire, said: “I know that by taking this action I risk losing my job, my livelihood and my reputation, but it’s what i have to do now.
“We must all do everything in our power to prevent this madness from continuing. There is a better, cleaner, safer future, but only if we fight for it.”
Just Stop Oil later said the orange substance was biodegradable cornstarch dyed with vegan dye.
In the video, Ms Goddard could be heard saying: “What’s the point of a garden if you can’t eat? What is the point of tradition if society collapses around you?”
A man interrupted the speech and yelled, “Nonsense.” However, other spectators applauded the protesters.
The disruption follows weeks of protest in the form of roadblocks in the capital and other forms of demonstration. The police were criticized for not acting more forcefully.